discovery-api/Overview.src.html
author Rich Tibbett <richt@opera.com>
Fri, 03 Aug 2012 12:59:17 +0200
changeset 180 ee3a89da06e1
child 181 a66764a2345e
child 191 5e0da09685f7
permissions -rw-r--r--
First draft of Networked Service Discovery and Messaging
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<!DOCTYPE html>
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<html>
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  <head>
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    <title>Networked Service Discovery and Messaging</title>
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    <meta http-equiv='Content-Type' content='text/html;charset=utf-8'/>
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    <!-- This spec has been compiled with ReSpec v2 -->
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    <script type="text/javascript" class='remove'>
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      var respecConfig = {
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          specStatus: "unofficial",
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          shortName:  "discovery",
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          edDraftURI: "http://dev.w3.org/2009/dap/discovery/",
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          editors: [
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                {   name:       "Rich Tibbett",
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                    //url:        "http://richt.me/",
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                    company:    "Opera Software ASA",
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                    companyURL: "http://opera.com/" },
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                {   name:       "Clarke Stevens",
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                    //url:      "",
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                    company:    "CableLabs",
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                    companyURL: "http://cablelabs.com/"
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                }
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          ],
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          //extraCSS:             ["./css/respec2.css"],
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          noIDLIn:  true,
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          wg:           "Device APIs and Policy Working Group",
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          wgURI:        "http://www.w3.org/2009/dap/",
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          wgPublicList: "public-device-apis",
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          wgPatentURI:  "http://www.w3.org/2004/01/pp-impl/43696/status",
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      };
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    </script>
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    <style type="text/css">
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      /**
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       * SyntaxHighlighter
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       * http://alexgorbatchev.com/SyntaxHighlighter
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       *
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       * SyntaxHighlighter is donationware. If you are using it, please donate.
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       * http://alexgorbatchev.com/SyntaxHighlighter/donate.html
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       *
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       * @version
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       * 3.0.83 (July 02 2010)
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       *
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       * @copyright
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       * Copyright (C) 2004-2010 Alex Gorbatchev.
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       *
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       * @license
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       * Dual licensed under the MIT and GPL licenses.
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       */
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    </style>
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    <style type="text/css">
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      /**
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       * SyntaxHighlighter
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       * http://alexgorbatchev.com/SyntaxHighlighter
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       *
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       * SyntaxHighlighter is donationware. If you are using it, please donate.
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       * http://alexgorbatchev.com/SyntaxHighlighter/donate.html
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       *
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       * @version
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       * 3.0.83 (July 02 2010)
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       *
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       * @copyright
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       * Copyright (C) 2004-2010 Alex Gorbatchev.
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       *
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       * @license
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       * Dual licensed under the MIT and GPL licenses.
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       */
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      div.example:before { content: "EXAMPLE"; font: bold small sans-serif; padding: 0.5em; background: red; color: white; position: absolute; top: 0; margin: -1px 0 0 -7.6em; width: 5em; border: thin solid red; border-radius: 0 0 0 0.5em }
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      dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
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      hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
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      dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
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      dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
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      dl.domintro dd p { margin: 0.5em 0; }
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      dl.domintro code {font-size: inherit; font-style: italic; }
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      dl.domintro:before { display: table; margin: -1em -0.5em 0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: red; border: solid 2px; background: white; padding: 0 0.25em; }
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    </style>
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  </head>
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   414
richt@180
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  <body>
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    <section id='abstract'>
richt@180
   417
      <p>
richt@180
   418
        This specification defines a mechanism for an HTML document to discover and subsequently communicate with <acronym title="Hypertext Transfer Protocol">HTTP</acronym>-based services
richt@180
   419
        advertised via common discovery protocols within a user's network.
richt@180
   420
      </p>
richt@180
   421
    </section>
richt@180
   422
richt@180
   423
    <section id='sotd'>
richt@180
   424
      <p>
richt@180
   425
        This document represents the early consensus of the group on the scope and features of the proposed
richt@180
   426
        API.
richt@180
   427
      </p>
richt@180
   428
    </section>
richt@180
   429
richt@180
   430
    <section class="informative">
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   431
      <h3>Introduction</h3>
richt@180
   432
richt@180
   433
      <p>To enable Web pages to connect and communicate with Local-networked Services provided over HTTP, this specification introduces the
richt@180
   434
      <a href="#navigatornetworkservice"><code>NavigatorNetworkService</code></a> interface.</p>
richt@180
   435
richt@180
   436
      <p>
richt@180
   437
         Using this <acronym title="Application Programming Interface">API</acronym> consists of requesting a well-known service type, known by developers and advertised by Local-networked Devices. User authorization, where the user connects the web page to one or more discovered services,
richt@180
   438
         is expected before the web page is able to interact with any Local-networked Services.
richt@180
   439
      </p>
richt@180
   440
richt@180
   441
      <p>
richt@180
   442
         A web page creates a request to obtain connectivity to services running in the network by specifying a well-known discovery service type that it wishes to interact with.
richt@180
   443
      </p>
richt@180
   444
richt@180
   445
      <p>
richt@180
   446
         The user agent, having captured all advertised services on the network from the Service Discovery mechanisms included in this recommendation, attempts to match
richt@180
   447
      the requested service type to a discovered service according to the processing described herein.
richt@180
   448
      </p>
richt@180
   449
richt@180
   450
      <p>
richt@180
   451
          If a service connectivity request is successful then the Web page is provided with the necessary information to communicate with the authorized Local-networked Service.
richt@180
   452
          If the request fails then the Web page will receive an error callback containing an error code describing the cause of Local-networked Service connectivity failure.
richt@180
   453
      </p>
richt@180
   454
richt@180
   455
      <p>
richt@180
   456
         Once connected to a Local-networked Service the Web page can send requests and receive responses to the Local-networked Service via the messaging format and appropriate channel inferred from the service type
richt@180
   457
         authorized via the provided API.
richt@180
   458
         The Web page, once connected, can also receive service-pushed events, in the messaging format supported by the Local-networked Device, if such event subscription functionality is provided by the
richt@180
   459
         connected Local-networked Service.
richt@180
   460
      </p>
richt@180
   461
richt@180
   462
      <div class="example">
richt@180
   463
       <p>Example of requesting a DNS-SD advertised service:</p>
richt@180
   464
       <hr />
richt@180
   465
       <pre class="brush:js">function showServices( services ) {
richt@180
   466
  // Show a list of all the services provided to the web page
richt@180
   467
  for(var i = 0, l = services.length; i < l; i++) console.log( services[i].name );
richt@180
   468
}
richt@180
   469
richt@180
   470
navigator.getNetworkServices('zeroconf:_boxee-jsonrpc._tcp', showServices);</pre>
richt@180
   471
      </div>
richt@180
   472
richt@180
   473
      <div class="example">
richt@180
   474
        <p>Example of requesting a UPnP advertised service, also handling error conditions:</p>
richt@180
   475
        <hr />
richt@180
   476
        <pre class="brush:js">function showServices( services ) {
richt@180
   477
  // Show a list of all the services provided to the web page
richt@180
   478
  for(var i = 0, l = services.length; i < l; i++) console.log( services[i].name );
richt@180
   479
}
richt@180
   480
richt@180
   481
function error( e ) {
richt@180
   482
  console.log( "Error occurred: " + e.code );
richt@180
   483
}
richt@180
   484
richt@180
   485
navigator.getNetworkServices('upnp:urn:schemas-upnp-org:service:ContentDirectory:1', showServices, error);</pre>
richt@180
   486
      </div>
richt@180
   487
richt@180
   488
      <div class="example">
richt@180
   489
        <p>Example of requesting either a DNS-SD or UPnP advertised service:</p>
richt@180
   490
        <hr />
richt@180
   491
        <pre class="brush:js">function showServices( services ) {
richt@180
   492
  // Show a list of all the services provided to the web page (+ service type)
richt@180
   493
  for(var i = 0, l = services.length; i < l; i++)
richt@180
   494
     console.log( services[i].name + '(' + services[i].type + ')' );
richt@180
   495
}
richt@180
   496
richt@180
   497
navigator.getNetworkServices([
richt@180
   498
  'zeroconf:_boxee-jsonrpc._tcp',
richt@180
   499
  'upnp:urn:schemas-upnp-org:service:ContentDirectory:1'
richt@180
   500
], showServices);</pre>
richt@180
   501
      </div>
richt@180
   502
richt@180
   503
      <p>For more detailed examples see the <a href="#examples">Examples</a> section.
richt@180
   504
    </section>
richt@180
   505
richt@180
   506
    <section
richt@180
   507
     id='conformance'>
richt@180
   508
richt@180
   509
     <p>Requirements phrased in the imperative as part of algorithms (such as "strip any leading space characters" or "return false and abort these steps") are to be interpreted with the
richt@180
   510
     meaning of the key word ("must", "should", "may", etc) used in introducing the algorithm.</p>
richt@180
   511
richt@180
   512
     <p>
richt@180
   513
      Some conformance requirements are phrased as requirements on attributes, methods or objects. Such requirements are to be interpreted as requirements on user agents.
richt@180
   514
     </p>
richt@180
   515
richt@180
   516
     <p>
richt@180
   517
      Conformance requirements phrased as algorithms or specific steps may be implemented in any manner, so long as the end result is equivalent. (In particular, the algorithms defined in
richt@180
   518
      this specification are intended to be easy to follow, and not intended to be performant.)
richt@180
   519
     </p>
richt@180
   520
richt@180
   521
     <p>
richt@180
   522
      The only conformance class defined by this specification is a <dfn>user agent</dfn>.
richt@180
   523
     </p>
richt@180
   524
richt@180
   525
     <p>
richt@180
   526
      User agents may impose implementation-specific limits on otherwise unconstrained inputs, e.g. to prevent denial of service attacks, to guard against running out of memory, or to work
richt@180
   527
      around platform-specific limitations.
richt@180
   528
     </p>
richt@180
   529
richt@180
   530
     <p>
richt@180
   531
      When support for a feature is disabled (e.g. as an emergency measure to mitigate a security problem, or to aid in development, or for performance reasons), user agents must act as if
richt@180
   532
      they had no support for the feature whatsoever, and as if the feature was not mentioned in this specification. For example, if a particular feature is accessed via an attribute in a Web
richt@180
   533
      IDL interface, the attribute itself would be omitted from the objects that implement that interface - leaving the attribute on the object but making it return null or throw an exception
richt@180
   534
      is insufficient.
richt@180
   535
     </p>
richt@180
   536
richt@180
   537
      <section>
richt@180
   538
         <h3>Dependencies</h3>
richt@180
   539
richt@180
   540
         This specification relies on several other underlying specifications.
richt@180
   541
richt@180
   542
         <dl>
richt@180
   543
            <dt>HTML</dt>
richt@180
   544
            <dd>Many fundamental concepts from HTML are used by this specification. [[!HTML5]]</dd>
richt@180
   545
            <dt>WebIDL</dt>
richt@180
   546
            <dd>The IDL blocks in this specification use the semantics of the WebIDL specification. [[!WEBIDL]]</dd>
richt@180
   547
         </dl>
richt@180
   548
      </section>
richt@180
   549
    </section>
richt@180
   550
richt@180
   551
    <section>
richt@180
   552
      <h3>Terminology</h3>
richt@180
   553
richt@180
   554
      <p>
richt@180
   555
         The construction "a <code>Foo</code> object", where <code>Foo</code> is actually an interface, is sometimes used instead of the more accurate "an object implementing the interface <code>Foo</code>".
richt@180
   556
      </p>
richt@180
   557
richt@180
   558
      <p>
richt@180
   559
         The term DOM is used to refer to the API set made available to scripts in Web applications, and does not necessarily imply the existence of an actual <code>Document</code> object or of any
richt@180
   560
         other <code>Node</code> objects as defined in the DOM Core specifications. [[!DOM-CORE]]
richt@180
   561
      </p>
richt@180
   562
richt@180
   563
      <p>
richt@180
   564
         An IDL attribute is said to be <em>getting</em> when its value is being retrieved (e.g. by author script), and is said to be <em>setting</em> when a new value is assigned to it.
richt@180
   565
      </p>
richt@180
   566
richt@180
   567
      <p>
richt@180
   568
        A <dfn>valid service type</dfn> is a string that begins with <code>upnp:</code> or <code>zeroconf:</code> followed by one or more characters in the ranges U+0021, U+0023 to U+0027, U+002A to U+002B, U+002D to U+002E, U+0030 to U+0039, U+0041 to U+005A, U+005E to U+007E.
richt@180
   569
      </p>
richt@180
   570
richt@180
   571
      <p>
richt@180
   572
        A <a>valid service type</a> provided in the <code>type</code> attribute of the <code>getNetworkServices()</code> method will be matched against the services currently contained in the <a>list of available service records</a> according to the algorithms defined in this specification.
richt@180
   573
      </p>
richt@180
   574
    </section>
richt@180
   575
richt@180
   576
    <section>
richt@180
   577
     <h2>Requesting networked services</h2>
richt@180
   578
richt@180
   579
richt@180
   580
<pre class="widl">[Supplemental, NoInterfaceObject]
richt@180
   581
interface <dfn id="navigatornetworkservice">NavigatorNetworkService</dfn> {
richt@180
   582
  // Obtain a Local-networked Service
richt@180
   583
  void <a href="#dom-navigator-getnetworkservices">getNetworkServices</a>( in any type,
richt@180
   584
                           in <a href="#navigatornetworkservicesuccesscallback">NavigatorNetworkServiceSuccessCallback</a> successCallback,
richt@180
   585
                           in optional <a href="#navigatornetworkserviceerrorcallback">NavigatorNetworkServiceErrorCallback</a> errorCallback );
richt@180
   586
};
richt@180
   587
<a class="externalDFN" href="http://www.whatwg.org/specs/web-apps/current-work/complete/timers.html#navigator">Navigator</a> implements <a href="#navigatornetworkservice">NavigatorNetworkService</a>;
richt@180
   588
richt@180
   589
[Callback=FunctionOnly, NoInterfaceObject]
richt@180
   590
interface <dfn id="navigatornetworkservicesuccesscallback">NavigatorNetworkServiceSuccessCallback</dfn> {
richt@180
   591
  void handleEvent( in <a href="#networkservices">NetworkServices</a> services );
richt@180
   592
};
richt@180
   593
richt@180
   594
[NoInterfaceObject]
richt@180
   595
interface <dfn id="navigatornetworkserviceerror">NavigatorNetworkServiceError</dfn> {
richt@180
   596
  const unsigned short <a href="#dom-navigatornetworkserviceerror-permission_denied">PERMISSION_DENIED_ERR</a> = 1;
richt@180
   597
  const unsigned short <a href="#dom-navigatornetworkserviceerror-unknown_type_prefix">UNKNOWN_TYPE_PREFIX_ERR</a> = 2;
richt@180
   598
  readonly attribute unsigned short <a href="#dom-navigatornetworkserviceerror-code">code</a>;
richt@180
   599
};
richt@180
   600
richt@180
   601
[Callback=FunctionOnly, NoInterfaceObject]
richt@180
   602
interface <dfn id="navigatornetworkserviceerrorcallback">NavigatorNetworkServiceErrorCallback</dfn> {
richt@180
   603
  void handleEvent( in <a href="#navigatornetworkserviceerror">NavigatorNetworkServiceError</a> error );
richt@180
   604
};
richt@180
   605
</pre>
richt@180
   606
richt@180
   607
  <section>
richt@180
   608
   <h2>Methods</h2>
richt@180
   609
richt@180
   610
      <dl class="domintro">
richt@180
   611
        <dt>
richt@180
   612
          <var title="">window</var>
richt@180
   613
           .
richt@180
   614
          <code title="dom-navigator">
richt@180
   615
            <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/timers.html#navigator">navigator</a>
richt@180
   616
          </code>
richt@180
   617
           .
richt@180
   618
          <code title="dom-navigator-getNetworkServices">
richt@180
   619
            <a href="#dom-navigator-getnetworkservices">getNetworkServices</a>
richt@180
   620
          </code>
richt@180
   621
          (
richt@180
   622
          <var title="">type</var>
richt@180
   623
          ,
richt@180
   624
          <var title="">successCallback</var>
richt@180
   625
           [,
richt@180
   626
          <var title="">errorCallback</var>
richt@180
   627
           ] )
richt@180
   628
        </dt>
richt@180
   629
        <dd>
richt@180
   630
          <p>Prompts the user to select one or more discovered network services that have advertised support for the requested service type.</p>
richt@180
   631
          <p>
richt@180
   632
            The
richt@180
   633
            <var title="">type</var>
richt@180
   634
             argument contains one or more <a>valid service type</a> tokens that the web page would like to interact with.
richt@180
   635
          </p>
richt@180
   636
          <p>
richt@180
   637
            If the user accepts, the
richt@180
   638
            <var title="">successCallback</var>
richt@180
   639
             is
richt@180
   640
          invoked, with one or more
richt@180
   641
            <code>
richt@180
   642
              <a href="#networkservice"><code>NetworkService</code></a>
richt@180
   643
            </code>
richt@180
   644
             objects as
richt@180
   645
          its argument.
richt@180
   646
          </p>
richt@180
   647
          <p>
richt@180
   648
            If the user declines, the
richt@180
   649
            <var title="">errorCallback</var>
richt@180
   650
             (if
richt@180
   651
          any) is invoked.
richt@180
   652
          </p>
richt@180
   653
        </dd>
richt@180
   654
      </dl>
richt@180
   655
richt@180
   656
       <div>
richt@180
   657
          <p>
richt@180
   658
            When the <dfn id="dom-navigator-getnetworkservices" title="dom-navigator-getnetworkservices"><code>getNetworkServices(type, successCallback[, errorCallback])</code></dfn> method is called, the <a>user agent</a> MUST run the following steps:
richt@180
   659
          </p>
richt@180
   660
richt@180
   661
          <ol class="rule">
richt@180
   662
            <li>
richt@180
   663
               If <var>successCallback</var> is empty or is not an object of type <code>Function</code> then the <a>user agent</a> MUST abort these steps.
richt@180
   664
            </li>
richt@180
   665
richt@180
   666
            <li>
richt@180
   667
              Let <var>requested control types</var> be initially set to an empty array.
richt@180
   668
            </li>
richt@180
   669
richt@180
   670
            <li>
richt@180
   671
               If <var>type</var> is an array consisting of one or more <a>valid service type</a> tokens, then let <var>requested control types</var> by the value of <var>type</var>, removing any non-<a>valid service type</a> tokens from the resulting array.
richt@180
   672
            </li>
richt@180
   673
richt@180
   674
            <li>
richt@180
   675
               If <var>type</var> is a string consisting of one <a>valid service type</a> token, then let <var>requested control types</var> be an array containing one item with a value of <var>type</var>.
richt@180
   676
            </li>
richt@180
   677
richt@180
   678
            <li>
richt@180
   679
               If <var>requested control types</var> is an array that contains at least one or more <a title="valid service type">valid service type</a> tokens then continue to the step labeled <em>process</em> below. Otherwise, the <a>user agent</a> MUST <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an object of type <code>Function</code>, with a new <a href="#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose
richt@180
   680
                 <a href="#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 2
richt@180
   681
                  (<a href="#dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a>) as its argument,
richt@180
   682
                   abort any remaining steps and return.
richt@180
   683
            </li>
richt@180
   684
richt@180
   685
            <li>
richt@180
   686
               <em>Process</em>: Let <var>services found</var> be an empty array.
richt@180
   687
            </li>
richt@180
   688
richt@180
   689
            <li>
richt@180
   690
               For each <var>available service</var> in the <a>list of available service records</a> run the following steps:
richt@180
   691
               <ol class="rule">
richt@180
   692
                  <li>
richt@180
   693
                    For each <var>requested control type</var> in <var>requested control types</var>: If <var>available service</var>'s <code>type</code> attribute equals the <var>requested control type</var> then let <var>matched service</var> equal the value of <var>available service</var> and continue at the step labeled <var>attach</var> below.
richt@180
   694
                  </li>
richt@180
   695
                  <li>
richt@180
   696
                     Continue at the next <var>available service</var>.
richt@180
   697
                  </li>
richt@180
   698
                  <li>
richt@180
   699
                     <em>Attach</em>: If <var>matched service</var> is not empty then run the following steps:
richt@180
   700
richt@180
   701
                     <ol class="rule">
richt@180
   702
                        <li>
richt@180
   703
                           Let <var>new service object</var> be a new <a href="#networkservice"><code>NetworkService</code></a> object, mapping the parameters of
richt@180
   704
                     <var>matched service</var> to this new object where possible.
richt@180
   705
                        </li>
richt@180
   706
                        <li>
richt@180
   707
                           Append <var>new service object</var> to the <var>services found</var> array.
richt@180
   708
                        </li>
richt@180
   709
                     </ol>
richt@180
   710
                  </li>
richt@180
   711
               </ol>
richt@180
   712
            </li>
richt@180
   713
richt@180
   714
            <li>
richt@180
   715
               If <var>services found</var> is an empty array, then the <a>user agent</a> MUST <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an object of type <code>Function</code>, with a new <a href="#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose
richt@180
   716
                 <a href="#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
richt@180
   717
                 (<a href="#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its argument, abort any remaining steps and return.
richt@180
   718
            </li>
richt@180
   719
richt@180
   720
            <li>
richt@180
   721
               Return, and run the remaining steps asynchronously.
richt@180
   722
            </li>
richt@180
   723
richt@180
   724
            <li>
richt@180
   725
               Optionally, e.g. based on a previously-established user preference, for security reasons, or due to platform limitations, the <a>user agent</a> MAY <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an object of type <code>Function</code>, with a new <a href="#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose
richt@180
   726
                 <a href="#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
richt@180
   727
                 (<a href="#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its argument, abort any remaining steps and return.
richt@180
   728
            </li>
richt@180
   729
richt@180
   730
            <li>
richt@180
   731
                  The <a>user agent</a> MUST prompt the user in a user-agent-specific manner for permission to provide the
richt@180
   732
                  <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/browsers.html#entry-script" class="externalDFN">entry script</a>'s
richt@180
   733
                  <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/origin-0.html#origin" class="externalDFN">origin</a> with an array of
richt@180
   734
                  <a href="#networkservice"><code>NetworkService</code></a> objects representing the user-authorized subset of <var>services found</var>.
richt@180
   735
richt@180
   736
               <p>
richt@180
   737
                  If the user grants permission to access one or more networked services then the <a>user agent</a> SHOULD include an
richt@180
   738
                  "ongoing local-network communication" indicator.
richt@180
   739
               </p>
richt@180
   740
richt@180
   741
               <p>If the user denies permission, then the <a>user agent</a> MUST <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an object of type <code>Function</code>, with a new <a href="#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose
richt@180
   742
                <a href="#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
richt@180
   743
                (<a href="#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its argument, abort any remaining steps and return.
richt@180
   744
              </p>
richt@180
   745
richt@180
   746
              <p>
richt@180
   747
                If the user never responds, this algorithm stalls on this step.
richt@180
   748
              </p>
richt@180
   749
richt@180
   750
            </li>
richt@180
   751
richt@180
   752
            <li>
richt@180
   753
               Let <var>services</var> be the array of one or more <a href="#networkservice"><code>NetworkService</code></a> objects for which the user granted permission.
richt@180
   754
            </li>
richt@180
   755
richt@180
   756
            <li>
richt@180
   757
               For each Object <var>service</var> in <var>services</var>, run the following substeps:
richt@180
   758
richt@180
   759
               <ol class="rule">
richt@180
   760
                  <li>
richt@180
   761
                     Add the <var>service</var>'s <code>url</code> parameter to the <a>entry script origin's <acronym title="Uniform Resource Locator">URL</acronym> whitelist</a>.
richt@180
   762
                  </li>
richt@180
   763
                  <li>
richt@180
   764
                    If <var>service</var> was originally created from a UPnP discovery process and the <var>service</var>'s <code>eventsUrl</code> parameter is not empty then <a>setup a UPnP Events Subscription</a> for <var>service</var>.
richt@180
   765
                  </li>
richt@180
   766
               </ol>
richt@180
   767
            </li>
richt@180
   768
richt@180
   769
            <li>
richt@180
   770
               Let <var>services manager</var> be a new <a href="#networkservices"><code>NetworkServices</code></a> object.
richt@180
   771
            </li>
richt@180
   772
richt@180
   773
            <li>
richt@180
   774
               Set <var>services manager</var>'s <code>servicesAvailable</code> attribute to the length of <var>services</var>.
richt@180
   775
            </li>
richt@180
   776
richt@180
   777
            <li>
richt@180
   778
              Store the set of <var>services</var> as <dfn id="current_authorized_services">current authorized services</dfn> internally against the newly created <var>services manager</var> object.
richt@180
   779
            </li>
richt@180
   780
richt@180
   781
            <li>
richt@180
   782
               The <a>user agent</a> MUST <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">queue a task</a> to invoke <var>successCallback</var> with
richt@180
   783
               <var>services manager</var> as its argument.
richt@180
   784
            </li>
richt@180
   785
richt@180
   786
          </ol>
richt@180
   787
richt@180
   788
          <p>
richt@180
   789
            The <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#task-source" class="externalDFN">task source</a> for these
richt@180
   790
            <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#concept-task" class="externalDFN">tasks</a> is the
richt@180
   791
            <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#user-interaction-task-source" class="externalDFN">user interaction task source</a>.
richt@180
   792
          </p>
richt@180
   793
richt@180
   794
          <p>
richt@180
   795
            When a <a href="#networkservice"><code>NetworkService</code></a> object is provided to a Web page, the <a>user agent</a> MUST add the <code>url</code> property
richt@180
   796
             to the <dfn>entry script origin's URL whitelist</dfn>. This list enables the
richt@180
   797
            Web page to override and initiate cross-site resource requests towards these URLs, and any sub-resources of these URLs, within the current
richt@180
   798
            <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/browsers.html#entry-script" class="externalDFN">entry script</a>'s
richt@180
   799
            <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/origin-0.html#origin" class="externalDFN">origin</a> via various existing mechanisms (e.g. Web Sockets, Server-Sent Events,
richt@180
   800
            Web Messaging, XMLHttpRequest).
richt@180
   801
         </p>
richt@180
   802
richt@180
   803
         <p>
richt@180
   804
            If the user navigates away from the current browsing context, the <a>user agent</a> MUST remove all previously whitelisted urls from the <a>entry script origin's URL whitelist</a>.
richt@180
   805
            There is no persistence to network service selections provided to a web page. It is not possible to access a previously white-listed networked service without the necessary user authorization in all of the following cases:
richt@180
   806
            <ul>
richt@180
   807
              <li>If the current script is reloaded at any point in the same or different window.</li>
richt@180
   808
              <li>if the current script reinvokes the <a href="#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method at any point in its execution.</li>
richt@180
   809
              <li>If the user navigates forward or back in their history to reload the current page.</li>
richt@180
   810
              <li>If a script is running in a different origin.</li>
richt@180
   811
            </ul>
richt@180
   812
         </p>
richt@180
   813
richt@180
   814
      </div>
richt@180
   815
      </section>
richt@180
   816
richt@180
   817
      <section>
richt@180
   818
         <h3>Error Handling</h3>
richt@180
   819
richt@180
   820
      <dl class="domintro">
richt@180
   821
        <dt>
richt@180
   822
          <var title="">error</var>
richt@180
   823
           .
richt@180
   824
          <code title="dom-NavigatorNetworkServiceError-code">
richt@180
   825
            <a href="#dom-navigatornetworkserviceerror-code">code</a>
richt@180
   826
          </code>
richt@180
   827
        </dt>
richt@180
   828
        <dd>
richt@180
   829
          <p>
richt@180
   830
            Returns the current error's error code. At the current time, this may be <code>1</code> or <code>2</code>, for which the
richt@180
   831
            corresponding error constants
richt@180
   832
            <a href="#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a> and
richt@180
   833
            <a href="#dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a> are defined.
richt@180
   834
          </p>
richt@180
   835
        </dd>
richt@180
   836
      </dl>
richt@180
   837
richt@180
   838
         <p>
richt@180
   839
            The <dfn id="dom-navigatornetworkserviceerror-code" title="dom-navigatornetworkserviceerror-code"><code>code</code></dfn> attribute of a
richt@180
   840
            <a href="#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object MUST return the code for the error, which will be one of the following:
richt@180
   841
         </p>
richt@180
   842
richt@180
   843
         <dl>
richt@180
   844
            <dt>
richt@180
   845
               <dfn id="dom-navigatornetworkserviceerror-permission_denied" title="dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></dfn> (numeric value 1)
richt@180
   846
            </dt>
richt@180
   847
            <dd>
richt@180
   848
               The user denied the page permission to access any services.
richt@180
   849
            </dd>
richt@180
   850
            <dt>
richt@180
   851
               <dfn id="dom-navigatornetworkserviceerror-unknown_type_prefix" title="dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></dfn> (numeric value 2)
richt@180
   852
            </dt>
richt@180
   853
            <dd>
richt@180
   854
               No <a>valid service type</a> tokens were provided in the method invocation.
richt@180
   855
            </dd>
richt@180
   856
         </dl>
richt@180
   857
richt@180
   858
      </section>
richt@180
   859
richt@180
   860
      </section>
richt@180
   861
      <section>
richt@180
   862
      <h2>Obtaining networked services</h2>
richt@180
   863
richt@180
   864
      <p>
richt@180
   865
         The <a href="#networkservices"><code>NetworkServices</code></a> interface is the top-level response object from a call to <a href="#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> and provides access to a set of user-authorized <a href="#networkservice"><code>NetworkService</code></a> objects for the given request.
richt@180
   866
      </p>
richt@180
   867
richt@180
   868
<pre class="widl">
richt@180
   869
[NoInterfaceObject]
richt@180
   870
interface <dfn id="networkservices">NetworkServices</dfn> {
richt@180
   871
  readonly attribute unsigned long    <a href="#dom-networkservices-length">length</a>;
richt@180
   872
  getter <a href="#networkservice">NetworkService</a> (unsigned long index);
richt@180
   873
  <a href="#networkservice">NetworkService</a>? <a href="#dom-networkservices-getservicebyid">getServiceById</a>(DOMString id);
richt@180
   874
richt@180
   875
  readonly attribute unsigned long    <a href="#dom-networkservices-servicesavailable">servicesAvailable</a>;
richt@180
   876
richt@180
   877
  // event handler attributes
richt@180
   878
           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler" class="externalDFN">EventHandler</a>     <a href="#dom-networkservices-onserviceavailable">onserviceavailable</a>;
richt@180
   879
           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler" class="externalDFN">EventHandler</a>     <a href="#dom-networkservices-onserviceunavailable">onserviceunavailable</a>;
richt@180
   880
richt@180
   881
};
richt@180
   882
richt@180
   883
<a href="#networkservices">NetworkServices</a> implements <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#interface-eventtarget" class="externalDFN">EventTarget</a>;
richt@180
   884
</pre>
richt@180
   885
richt@180
   886
      <section>
richt@180
   887
      <h2>Attributes</h2>
richt@180
   888
richt@180
   889
        <dl class="domintro">
richt@180
   890
          <dt>
richt@180
   891
            <code title="dom-networkservices-length">
richt@180
   892
              <a href="#dom-networkservices-length">length</a>
richt@180
   893
            </code>
richt@180
   894
          </dt>
richt@180
   895
          <dd>
richt@180
   896
            <p>
richt@180
   897
              Returns the current number of services in the respective object's <a>current authorized services</a>.
richt@180
   898
            </p>
richt@180
   899
          </dd>
richt@180
   900
          <dt>
richt@180
   901
            <code title="dom-networkservices-servicesavailable">
richt@180
   902
              <a href="#dom-networkservices-servicesavailable">servicesAvailable</a>
richt@180
   903
            </code>
richt@180
   904
          </dt>
richt@180
   905
          <dd>
richt@180
   906
            <p>
richt@180
   907
              Returns the current number of services matching one of the app-requested <a>valid service type</a> tokens that are actively available within the user's current network.
richt@180
   908
            </p>
richt@180
   909
          </dd>
richt@180
   910
        </dl>
richt@180
   911
richt@180
   912
        <div>
richt@180
   913
           <p>
richt@180
   914
              The <dfn id="dom-networkservices-length"><code>length</code></dfn> attribute MUST return the number of services represented in the object's corresponding <a>current authorized services</a> list at the time of getting.
richt@180
   915
           </p>
richt@180
   916
richt@180
   917
           <p>
richt@180
   918
              The <dfn id="dom-networkservices-servicesavailable"><code>servicesAvailable</code></dfn> attribute MUST return the number of services available in the
richt@180
   919
              user's network that match the <a>valid service type</a> that was initially used to create the current <a href="#networkservices"><code>NetworkServices</code></a> object.
richt@180
   920
              By default, <a href="#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> MUST be set to <code>1</code>.
richt@180
   921
           </p>
richt@180
   922
richt@180
   923
           <p>
richt@180
   924
             When a previously unknown instance of a networked service matching one or the requested <a href="#dfn-valid-service-type">valid service types</a> becomes available on the user's current network, the <a>user agent</a> MUST fire a new simple
richt@180
   925
             event at the <a href="#dom-networkservices-onserviceavailable"><code>onserviceavailable</code></a> event handler.
richt@180
   926
           </p>
richt@180
   927
richt@180
   928
           <p>
richt@180
   929
             When a previously known instance of a networked service matching one or the requested <a href="#dfn-valid-service-type">valid service types</a> becomes unavailable on the user's current network, the <a>user agent</a> MUST fire a new simple
richt@180
   930
             event at the <a href="#dom-networkservices-onserviceunavailable"><code>onserviceunavailable</code></a> event handler.
richt@180
   931
           </p>
richt@180
   932
        </div>
richt@180
   933
richt@180
   934
      </section>
richt@180
   935
richt@180
   936
      <section>
richt@180
   937
      <h2>Methods</h2>
richt@180
   938
        <dl class="domintro">
richt@180
   939
        <dt>
richt@180
   940
          <code title="networkservices-getter">
richt@180
   941
            <a href="#networkservices">services</a>
richt@180
   942
          </code>
richt@180
   943
          [
richt@180
   944
          <var title="">index</var>
richt@180
   945
          ]
richt@180
   946
        </dt>
richt@180
   947
        <dd>
richt@180
   948
          <p>
richt@180
   949
            Returns the specified <a href="#networkservice"><code>NetworkService</code></a> object.
richt@180
   950
          </p>
richt@180
   951
        </dd>
richt@180
   952
        <dt>
richt@180
   953
          <code title="networkservices-getter">
richt@180
   954
            <a href="#networkservices">services</a>
richt@180
   955
          </code>
richt@180
   956
          .
richt@180
   957
          <code title="dom-networkservices-getservicebyid">
richt@180
   958
            <a href="#dom-networkservices-getservicebyid">getServiceById</a>
richt@180
   959
          </code>
richt@180
   960
          (
richt@180
   961
          <var title="">id</var>
richt@180
   962
          )
richt@180
   963
        </dt>
richt@180
   964
        <dd>
richt@180
   965
          <p>
richt@180
   966
            Returns the <a href="#networkservice"><code>NetworkService</code></a> object with the given identifier, or null if no
richt@180
   967
            service has that identifier.
richt@180
   968
          </p>
richt@180
   969
        </dd>
richt@180
   970
      </dl>
richt@180
   971
richt@180
   972
      <p>
richt@180
   973
        A <a href="#networkservices"><code>NetworkServices</code></a> object represents the current list of zero or more <a>current authorized services</a>, of which zero or more can be available at a time. Each item in <a>current authorized services</a> is represented by a <a href="#networkservice"><code>NetworkService</code></a> object.
richt@180
   974
      </p>
richt@180
   975
richt@180
   976
      <p class="note">
richt@180
   977
        Each service in a <a href="#networkservices"><code>NetworkServices</code></a> object thus has an index; the first has the index 0, and each subsequent service is numbered one higher than the previous one. If the <a>user agent</a> dynamically adds or removes network services for any reason, then the indices of the services in <a>current authorized services</a> will change dynamically. If the set of network services changes entirely, then all the previous services will be removed from <a>current authorized services</a> and replaced with new services.
richt@180
   978
      </p>
richt@180
   979
richt@180
   980
      <p>
richt@180
   981
        The <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.html#supported-property-indices" class="externalDFN">supported property indices</a> of <a href="#networkservices"><code>NetworkServices</code></a> objects at any instant are the numbers from zero to the number of items in <a>current authorized services</a> represented by the respective object minus one, if any services are represented in <a>current authorized services</a>. If a <a href="#networkservices"><code>NetworkServices</code></a> object represents no <a>current authorized services</a>, it has no <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.html#supported-property-indices" class="externalDFN">supported property indices</a>.
richt@180
   982
      </p>
richt@180
   983
richt@180
   984
      <p>
richt@180
   985
        To <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.html#determine-the-value-of-an-indexed-property" class="externalDFN">determine the value of an indexed property</a> for a given index <var>index</var> in a <a href="#networkservices"><code>NetworkServices</code></a> object's <a>current authorized services</a>, the user agent MUST return the <a href="#networkservice"><code>NetworkService</code></a> object that represents the <var>index</var>th service in <a>current authorized services</a>.
richt@180
   986
      </p>
richt@180
   987
richt@180
   988
      <p>
richt@180
   989
        The <dfn id="dom-networkservices-getservicebyid"><code>getServiceById(id)</code></dfn> method MUST return the first <a href="#networkservice"><code>NetworkService</code></a> object in <a>current authorized services</a> represented by the respective object whose <a href="#dom-networkservice-id"><code>id</code></a> attribute is equal to the value of the <var>id</var> argument.
richt@180
   990
        When no services in <a>current authorized services</a> match the given argument, the method MUST return null.
richt@180
   991
      </p>
richt@180
   992
richt@180
   993
      <p>
richt@180
   994
         Services available within the local network can connect and disconnect at different times during the execution of a web page. A <a>user agent</a> can
richt@180
   995
         inform a web page when the state of networked services matching the requested <a>valid service type</a> change. Web pages can use this information to enable in-page experiences for communicating the state of networked services
richt@180
   996
         with the ability to change the particular service or set of services the page is connected to by re-invoking the <a href="#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method.
richt@180
   997
      </p>
richt@180
   998
richt@180
   999
      </section>
richt@180
  1000
richt@180
  1001
      <section>
richt@180
  1002
      <h2>Events</h2>
richt@180
  1003
richt@180
  1004
      <p>
richt@180
  1005
         The following are the event handlers (and their corresponding event handler event types) that must be supported, as IDL attributes, by all objects implementing the <a href="#networkservices"><code>NetworkServices</code></a> interface:
richt@180
  1006
       </p>
richt@180
  1007
richt@180
  1008
       <table border="1">
richt@180
  1009
        <thead>
richt@180
  1010
          <tr>
richt@180
  1011
            <th>
richt@180
  1012
              <span title="event handlers">Event handler</span>
richt@180
  1013
            </th>
richt@180
  1014
            <th>
richt@180
  1015
              <span>Event handler event type</span>
richt@180
  1016
            </th>
richt@180
  1017
          </tr>
richt@180
  1018
        </thead>
richt@180
  1019
        <tbody>
richt@180
  1020
          <tr>
richt@180
  1021
            <td>
richt@180
  1022
              <dfn id="dom-networkservices-onserviceavailable" title="dom-NetworkServices-onserviceavailable">
richt@180
  1023
                <code>onserviceavailable</code>
richt@180
  1024
              </dfn>
richt@180
  1025
            </td>
richt@180
  1026
            <td>
richt@180
  1027
              <code title="event-serviceavailable">serviceavailable</code>
richt@180
  1028
            </td>
richt@180
  1029
          </tr>
richt@180
  1030
          <tr>
richt@180
  1031
            <td>
richt@180
  1032
              <dfn id="dom-networkservices-onserviceunavailable" title="dom-NetworkServices-onserviceunavailable">
richt@180
  1033
                <code>onserviceunavailable</code>
richt@180
  1034
              </dfn>
richt@180
  1035
            </td>
richt@180
  1036
            <td>
richt@180
  1037
              <code title="event-serviceunavailable">serviceunavailable</code>
richt@180
  1038
            </td>
richt@180
  1039
          </tr>
richt@180
  1040
        </tbody>
richt@180
  1041
      </table>
richt@180
  1042
richt@180
  1043
      <p>
richt@180
  1044
         Events with an event type of <code>serviceavailable</code> or <code>serviceunavailable</code> defined in this specification are simple <code>Event</code> objects.
richt@180
  1045
      </p>
richt@180
  1046
richt@180
  1047
      </section>
richt@180
  1048
richt@180
  1049
    </section>
richt@180
  1050
    <section>
richt@180
  1051
    <h2>Communicating with a networked service</h3>
richt@180
  1052
richt@180
  1053
<p>
richt@180
  1054
   The <a href="#networkservice"><code>NetworkService</code></a> interface is used to provide a set of connection information for an HTTP service endpoint and if available, service events, running on a networked device.
richt@180
  1055
</p>
richt@180
  1056
richt@180
  1057
<pre class="widl">
richt@180
  1058
[NoInterfaceObject]
richt@180
  1059
interface <dfn id="networkservice">NetworkService</dfn> {
richt@180
  1060
  readonly attribute DOMString        <a href="#dom-networkservice-id">id</a>;
richt@180
  1061
  readonly attribute DOMString        <a href="#dom-networkservice-name">name</a>;
richt@180
  1062
  readonly attribute DOMString        <a href="#dom-networkservice-type">type</a>;
richt@180
  1063
  readonly attribute DOMString        <a href="#dom-networkservice-url">url</a>;
richt@180
  1064
  readonly attribute DOMString        <a href="#dom-networkservice-config">config</a>;
richt@180
  1065
richt@180
  1066
  const unsigned short <a href="#dom-networkservice-AVAILABLE">AVAILABLE</a>      = 1;
richt@180
  1067
  const unsigned short <a href="#dom-networkservice-UNAVAILABLE">UNAVAILABLE</a>    = 2;
richt@180
  1068
  readonly attribute unsigned short   <a href="#dom-networkservice-readystate">readyState</a>;
richt@180
  1069
richt@180
  1070
  // event handler attributes
richt@180
  1071
           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler" class="externalDFN">EventHandler</a>     <a href="#dom-networkservice-onreadystatechange">onreadystatechange</a>;
richt@180
  1072
           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler" class="externalDFN">EventHandler</a>     <a href="#dom-networkservice-onmessage">onmessage</a>;
richt@180
  1073
};
richt@180
  1074
richt@180
  1075
<a href="#networkservice">NetworkService</a> implements <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#interface-eventtarget" class="externalDFN">EventTarget</a>;
richt@180
  1076
</pre>
richt@180
  1077
richt@180
  1078
<section>
richt@180
  1079
  <h2>Attributes</h2>
richt@180
  1080
richt@180
  1081
      <dl class="domintro">
richt@180
  1082
        <dt>
richt@180
  1083
          <var title="">service</var>
richt@180
  1084
           .
richt@180
  1085
          <code title="dom-networkservice-id">
richt@180
  1086
            <a href="#dom-networkservice-id">id</a>
richt@180
  1087
          </code>
richt@180
  1088
        </dt>
richt@180
  1089
        <dd>
richt@180
  1090
          <p>
richt@180
  1091
            A unique identifier for the given user-selected service instance.
richt@180
  1092
          </p>
richt@180
  1093
        </dd>
richt@180
  1094
        <dt>
richt@180
  1095
          <var title="">service</var>
richt@180
  1096
           .
richt@180
  1097
          <code title="dom-networkservice-name">
richt@180
  1098
            <a href="#dom-networkservice-name">name</a>
richt@180
  1099
          </code>
richt@180
  1100
        </dt>
richt@180
  1101
        <dd>
richt@180
  1102
          <p>
richt@180
  1103
            The name of the user-selected service.
richt@180
  1104
          </p>
richt@180
  1105
        </dd>
richt@180
  1106
        <dt>
richt@180
  1107
          <var title="">service</var>
richt@180
  1108
           .
richt@180
  1109
          <code title="dom-networkservice-type">
richt@180
  1110
            <a href="#dom-networkservice-type">type</a>
richt@180
  1111
          </code>
richt@180
  1112
        </dt>
richt@180
  1113
        <dd>
richt@180
  1114
          <p>
richt@180
  1115
            The <a>valid service type</a> token value of the user-selected service.
richt@180
  1116
          </p>
richt@180
  1117
        </dd>
richt@180
  1118
        <dt>
richt@180
  1119
          <var title="">service</var>
richt@180
  1120
           .
richt@180
  1121
          <code title="dom-networkservice-url">
richt@180
  1122
            <a href="#dom-networkservice-url">url</a>
richt@180
  1123
          </code>
richt@180
  1124
        </dt>
richt@180
  1125
        <dd>
richt@180
  1126
          <p>
richt@180
  1127
            The control URL endpoint (including any required port information) of the user-selected control service that has been added to the <a>entry script origin's URL whitelist</a>.
richt@180
  1128
          </p>
richt@180
  1129
        </dd>
richt@180
  1130
        <dt>
richt@180
  1131
          <var title="">service</var>
richt@180
  1132
           .
richt@180
  1133
          <code title="dom-networkservice-config">
richt@180
  1134
            <a href="#dom-networkservice-config">config</a>
richt@180
  1135
          </code>
richt@180
  1136
        </dt>
richt@180
  1137
        <dd>
richt@180
  1138
          <p>
richt@180
  1139
            The configuration information associated with the service depending on the requested service type.
richt@180
  1140
          </p>
richt@180
  1141
        </dd>
richt@180
  1142
      </dl>
richt@180
  1143
richt@180
  1144
          <p>
richt@180
  1145
            The <dfn id="dom-networkservice-id"><code>id</code></dfn> attribute is a unique identifier for the service. Two services provided at different times or on different objects MUST have the same <a href="#dom-networkservice-id"><code>id</code></a> value.
richt@180
  1146
         </p>
richt@180
  1147
richt@180
  1148
         <p>
richt@180
  1149
            The <dfn id="dom-networkservice-name"><code>name</code></dfn> attribute represents a human-readable title for the service.
richt@180
  1150
         </p>
richt@180
  1151
richt@180
  1152
         <p>
richt@180
  1153
             The <dfn id="dom-networkservice-type"><code>type</code></dfn> attribute reflects the value of the <a>valid service type</a> of the service.
richt@180
  1154
          </p>
richt@180
  1155
richt@180
  1156
         <p>
richt@180
  1157
            The <dfn id="dom-networkservice-url"><code>url</code></dfn> attribute is an <a href="http://www.w3.org/TR/html5/urls.html#absolute-url" class="externalDFN">absolute URL</a> pointing to the root HTTP
richt@180
  1158
            endpoint for the service that has been added to the <a>entry script origin's URL whitelist</a>. Web pages can subsequently use this value for implicit cross-document messaging via various existing mechanisms (e.g. Web Sockets, Server-Sent Events, Web Messaging, XMLHttpRequest).
richt@180
  1159
         </p>
richt@180
  1160
richt@180
  1161
         <p>
richt@180
  1162
            The <dfn id="dom-networkservice-config"><code>config</code></dfn> attribute provides the raw configuration information extracted from the given network service.
richt@180
  1163
         </p>
richt@180
  1164
richt@180
  1165
      </section>
richt@180
  1166
richt@180
  1167
      <section>
richt@180
  1168
         <h3>States</h3>
richt@180
  1169
richt@180
  1170
      <dl class="domintro">
richt@180
  1171
        <dt>
richt@180
  1172
          <var title="">service</var>
richt@180
  1173
           .
richt@180
  1174
          <code title="dom-networkservice-readystate">
richt@180
  1175
            <a href="#dom-networkservice-readystate">readyState</a>
richt@180
  1176
          </code>
richt@180
  1177
        </dt>
richt@180
  1178
        <dd>
richt@180
  1179
          <p>
richt@180
  1180
            Returns the current state.
richt@180
  1181
          </p>
richt@180
  1182
        </dd>
richt@180
  1183
      </dl>
richt@180
  1184
richt@180
  1185
         A <a href="#networkservice"><code>NetworkService</code></a> object can be in several states. The <dfn id="dom-networkservice-readystate"><code>readyState</code></dfn> attribute MUST return the current state of the networked service,
richt@180
  1186
         which MUST be one of the following values:
richt@180
  1187
richt@180
  1188
         <dl>
richt@180
  1189
           <dt>
richt@180
  1190
             <dfn id="dom-networkservice-AVAILABLE" title="dom-networkservice-AVAILABLE">
richt@180
  1191
               <code>AVAILABLE</code>
richt@180
  1192
             </dfn>
richt@180
  1193
              (numeric value
richt@180
  1194
             1)
richt@180
  1195
richt@180
  1196
richt@180
  1197
           </dt>
richt@180
  1198
           <dd>
richt@180
  1199
             <p>The object is connected to its service endpoint.
richt@180
  1200
richt@180
  1201
            </p>
richt@180
  1202
           </dd>
richt@180
  1203
           <dt>
richt@180
  1204
             <dfn id="dom-networkservice-UNAVAILABLE" title="dom-networkservice-UNAVAILABLE">
richt@180
  1205
               <code>UNAVAILABLE</code>
richt@180
  1206
             </dfn>
richt@180
  1207
              (numeric value
richt@180
  1208
             2)
richt@180
  1209
           </dt>
richt@180
  1210
           <dd>
richt@180
  1211
             <p>The object is not connected to its service endpoint.
richt@180
  1212
            </p>
richt@180
  1213
           </dd>
richt@180
  1214
         </dl>
richt@180
  1215
richt@180
  1216
      </section>
richt@180
  1217
richt@180
  1218
      <section>
richt@180
  1219
         <h3>Events</h3>
richt@180
  1220
richt@180
  1221
      <p>
richt@180
  1222
         The following are the event handlers (and their corresponding event handler event types) that must be supported, as IDL attributes, by all objects implementing the
richt@180
  1223
         <a href="#networkservice"><code>NetworkService</code></a> interface:
richt@180
  1224
       </p>
richt@180
  1225
richt@180
  1226
       <table border="1">
richt@180
  1227
        <thead>
richt@180
  1228
          <tr>
richt@180
  1229
            <th>
richt@180
  1230
              <span title="event handlers">Event handler</span>
richt@180
  1231
            </th>
richt@180
  1232
            <th>
richt@180
  1233
              <span>Event handler event type</span>
richt@180
  1234
            </th>
richt@180
  1235
          </tr>
richt@180
  1236
        </thead>
richt@180
  1237
        <tbody>
richt@180
  1238
          <tr>
richt@180
  1239
            <td>
richt@180
  1240
              <dfn id="dom-networkservice-onmessage" title="dom-NetworkService-onmessage">
richt@180
  1241
                <code>onmessage</code>
richt@180
  1242
              </dfn>
richt@180
  1243
            </td>
richt@180
  1244
            <td>
richt@180
  1245
              <code title="event-message">message</code>
richt@180
  1246
            </td>
richt@180
  1247
          </tr>
richt@180
  1248
          <tr>
richt@180
  1249
            <td>
richt@180
  1250
              <dfn id="dom-networkservice-onreadystatechange" title="dom-NetworkService-onreadystatechange">
richt@180
  1251
                <code>onreadystatechange</code>
richt@180
  1252
              </dfn>
richt@180
  1253
            </td>
richt@180
  1254
            <td>
richt@180
  1255
              <code title="event-onreadystatechange">readystatechange</code>
richt@180
  1256
            </td>
richt@180
  1257
          </tr>
richt@180
  1258
        </tbody>
richt@180
  1259
      </table>
richt@180
  1260
richt@180
  1261
      <p>
richt@180
  1262
         Events with an event type of <code>message</code> defined in this specification are <a href="http://dev.w3.org/html5/postmsg/#messageevent" class="externalDFN"><code>MessageEvent</code></a> objects as defined in [[!WEBMESSAGING]].
richt@180
  1263
      </p>
richt@180
  1264
richt@180
  1265
      <p>
richt@180
  1266
         Events with an event type of <code>readystatechange</code> defined in this specification are simple <code>Event</code> objects.
richt@180
  1267
      </p>
richt@180
  1268
richt@180
  1269
      </section>
richt@180
  1270
   </section>
richt@180
  1271
richt@180
  1272
      <section>
richt@180
  1273
            <h2>Service Discovery</h2>
richt@180
  1274
richt@180
  1275
      <p>
richt@180
  1276
         A <a>user agent</a> conforming to this specification MAY implement <acronym title="Simple Service Discovery Protocol">SSDP</acronym> [[!UPNP]] and Zeroconf [[!ZEROCONF]] service discovery mechanisms
richt@180
  1277
         to enable Web pages to request and connect with HTTP services running on networked devices, discovered via either mechanism, through this API. When a <a>user agent</a> implements either of these service discovery mechanisms, then it MUST conform to the corresponding algorithms provided in this section of the specification.
richt@180
  1278
      </p>
richt@180
  1279
      <p>
richt@180
  1280
         This section presents how the results of these two service discovery
richt@180
  1281
         mechanisms will be matched to requested service types and how their properties will be applied to any resulting <a href="#networkservice"><code>NetworkService</code></a> objects.
richt@180
  1282
      </p>
richt@180
  1283
richt@180
  1284
      <p>
richt@180
  1285
         It is expected that user agents will perform these service discovery mechansisms asynchronously and periodically update the <a>list of networked devices</a> as required. The timing of any
richt@180
  1286
         service discovery mechanisms is an implementation detail left to the discretion of the implementer (e.g. once on user agent start-up, every X seconds during user agent execution or on
richt@180
  1287
         invocation of this API from a Web page).
richt@180
  1288
      </p>
richt@180
  1289
richt@180
  1290
      <p>
richt@180
  1291
         The <dfn>list of available service records</dfn> is a single dynamic internal lookup table within user agents that is used to track the current services available in the network at any given time.
richt@180
  1292
         At any point during the running of either of the two service discovery mechanisms then existing entries within this table can be updated, entries can be added and entries can be removed as the status of networked
richt@180
  1293
         services changes. Each record contained within this table contains the attributes: <code>id</code>, <code>name</code>, <code>type</code>, <code>url</code> and <code>config</code>.
richt@180
  1294
      </p>
richt@180
  1295
richt@180
  1296
            <section>
richt@180
  1297
         <h4>Zeroconf (<acronym title="Multicast DNS">mDNS</acronym> + <acronym title="Domain Name System">DNS</acronym>-<acronym title="Service Discovery">SD</acronym>)</h4>
richt@180
  1298
richt@180
  1299
         <p>
richt@180
  1300
            For each DNS response received from a user-agent-initiated Multicast DNS Browse for <acronym title="DNS Pointer Record">PTR</acronym> records with the name <code>_services._dns-sd._udp</code> on the resolved recommended automatic browsing
richt@180
  1301
   domain [[!MDNS]], the <a>user agent</a> MUST run the following steps:
richt@180
  1302
         </p>
richt@180
  1303
richt@180
  1304
         <ol class="rule">
richt@180
  1305
richt@180
  1306
            <li>Let <var>service mDNS responses</var> be an array of PTR records received by issuing a Multicast DNS Browse for PTR records with the name of the current discovered service type.</li>
richt@180
  1307
richt@180
  1308
            <li>For each Object <var>service mDNS response</var> in <var>service mDNS responses</var>, run the following steps:
richt@180
  1309
               <ol>
richt@180
  1310
richt@180
  1311
                  <li>
richt@180
  1312
                     Let <var>network service record</var> be an Object consisting of the following empty properties: <code>id</code>, <code>name</code>, <code>type</code>, <code>url</code>, <code>config</code>.
richt@180
  1313
                  </li>
richt@180
  1314
richt@180
  1315
                  <li>
richt@180
  1316
                     Set <var>network service record</var>'s <code>id</code> property to the value of the full PTR Service Instance Name [[!MDNS]].
richt@180
  1317
                  </li>
richt@180
  1318
richt@180
  1319
                  <li>
richt@180
  1320
                     Set <var>network service record</var>'s <code>name</code> property to the value of the PTR Service Instance Name's <var>Instance</var> component [[!MDNS]].
richt@180
  1321
                  </li>
richt@180
  1322
richt@180
  1323
                  <li>
richt@180
  1324
                     Set <var>network service record</var>'s <code>type</code> property to the concatenation of the string <code>zeroconf:</code> followed by the value of the PTR Service Instance Name's <var>Service</var> component [[!MDNS]].
richt@180
  1325
                  </li>
richt@180
  1326
richt@180
  1327
                  <li>
richt@180
  1328
                     Set <var>network service record</var>'s <code>url</code> property to the resolvable Service URL obtained from performing an DNS-SD Lookup [[!DNS-SD]] of the current service from the PTR record provided [[!MDNS]].
richt@180
  1329
                  </li>
richt@180
  1330
richt@180
  1331
                  <li>
richt@180
  1332
                     Set <var>network service record</var>'s <code>config</code> property to the string value of the contents of the first DNS-SD TXT record associated with the <var>service mDNS response</var> as defined in [[!DNS-SD]].
richt@180
  1333
                  </li>
richt@180
  1334
richt@180
  1335
                  <li>
richt@180
  1336
                     For each Object <var>existing service record</var> in the current <a>list of available service records</a>, run the following sub-steps:
richt@180
  1337
                     <ol class="rule">
richt@180
  1338
richt@180
  1339
                       <li>
richt@180
  1340
                        If the <var>existing service record</var>'s <code>id</code> property matches the value of the <var>network service record</var>'s <code>id</code>, then set the
richt@180
  1341
                        value of <var>existing service record</var> in the current <a>list of available service records</a>  to the value of the
richt@180
  1342
                        <var>network service record</var> and skip the next step.
richt@180
  1343
                       </li>
richt@180
  1344
                     </ol>
richt@180
  1345
                  </li>
richt@180
  1346
richt@180
  1347
                  <li>
richt@180
  1348
                     Add <var>network service record</var> to the <a>list of available service records</a>.
richt@180
  1349
                  </li>
richt@180
  1350
richt@180
  1351
                  <li>
richt@180
  1352
                     For each non-garbage collected <a href="#networkservice"><code>NetworkService</code></a> object run the following steps:
richt@180
  1353
richt@180
  1354
                     <ol class="rule">
richt@180
  1355
                        <li>
richt@180
  1356
                           If the <a href="#networkservice"><code>NetworkService</code></a> object's <code>type</code> attribute does not equal the
richt@180
  1357
                           current <a>network service record</a>'s <code>type</code> property then continue at the next available active
richt@180
  1358
                           <a href="#networkservice"><code>NetworkService</code></a> object.
richt@180
  1359
                        </li>
richt@180
  1360
                        <li>
richt@180
  1361
                           Increment the <code>servicesAvailable</code> attribute of the <a href="#networkservices"><code>NetworkServices</code></a> object by <code>1</code>.
richt@180
  1362
                        </li>
richt@180
  1363
                     </ol>
richt@180
  1364
                  </li>
richt@180
  1365
            </ol>
richt@180
  1366
           </li>
richt@180
  1367
         </ol>
richt@180
  1368
richt@180
  1369
      </section>
richt@180
  1370
richt@180
  1371
      <section>
richt@180
  1372
         <h5>Universal Plug-and-Play (<acronym title="Universal Plug-and-Play">UPnP</acronym>)</h5>
richt@180
  1373
richt@180
  1374
         <p>
richt@180
  1375
            For each SSDP Presence Announcement [[!UPNP]] - a HTTP NOTIFY request - received from a user-agent-initiated SSDP Discovery Request [[!UPNP]], the <a>user agent</a> MUST run the following steps:
richt@180
  1376
         </p>
richt@180
  1377
richt@180
  1378
         <ol class="rule">
richt@180
  1379
            <li>
richt@180
  1380
               Let <var>ssdp device</var> be an Object with a property for each HTTP header received in the received SSDP Presence Announcement, with each key being the name of a HTTP header and its
richt@180
  1381
               value being that HTTP header's accompanying value.
richt@180
  1382
            </li>
richt@180
  1383
richt@180
  1384
            <li>
richt@180
  1385
               If <var>ssdp device</var> does not contain at least one <var>NTS</var>, <var>USN</var> and <var>Location</var> parameter, then the <a>user agent</a> MUST abort these steps.
richt@180
  1386
            </li>
richt@180
  1387
richt@180
  1388
            <li>
richt@180
  1389
               If the first occurrence of <var>NTS</var> has a value other than <code>ssdp:alive</code>, then continue to the step labeled <var>update service monitor</var> below.
richt@180
  1390
            </li>
richt@180
  1391
richt@180
  1392
            <li>
richt@180
  1393
               Let <var>root device descriptor file</var> contain the contents of the file located at the URL provided in the first occurrence of <var>Location</var> obtained according to the rules
richt@180
  1394
               defined in the section 'Retrieving a description using HTTP' [[!UPNP]].
richt@180
  1395
            </li>
richt@180
  1396
richt@180
  1397
            <li>
richt@180
  1398
               If <var>root device descriptor file</var> is empty, then the <a>user agent</a> MUST abort these steps.
richt@180
  1399
            </li>
richt@180
  1400
richt@180
  1401
            <li>
richt@180
  1402
               Let <var>advertised services</var> be a <a>list of all advertised services</a> obtained from the <var>root device descriptor file</var> containing all sub-nodes of the <code>serviceList</code> node as described in
richt@180
  1403
               the section 'Device Description' [[!UPNP]].
richt@180
  1404
            </li>
richt@180
  1405
richt@180
  1406
            <li>
richt@180
  1407
               For each Object <var>advertised service</var> in <var>advertised services</var> run the following steps:
richt@180
  1408
               <ol class="rule">
richt@180
  1409
richt@180
  1410
                  <li>
richt@180
  1411
                     Let <var>network service record</var> be an Object consisting of the following empty properties: <code>id</code>, <code>name</code>, <code>type</code>, <code>url</code>, <code>eventsUrl</code>, <code>config</code>.
richt@180
  1412
                  </li>
richt@180
  1413
richt@180
  1414
                  <li>
richt@180
  1415
                     Set <var>network service record</var>'s <code>id</code> property to the string value of the first occurrence of <var>ssdp device</var>'s <var>USN</var> parameter.
richt@180
  1416
                  </li>
richt@180
  1417
richt@180
  1418
                  <li>
richt@180
  1419
                     Set <var>network service record</var>'s <code>name</code> property to the string value of the first occurrence of the <var>service</var>'s <code>serviceId</code> property.
richt@180
  1420
                  </li>
richt@180
  1421
richt@180
  1422
                  <li>
richt@180
  1423
                     Set <var>network service record</var>'s <code>type</code> property to the concatenation of the string <code>upnp:</code> followed by the string value of the first occurrence of the <var>service</var>'s <code>serviceType</code> property.
richt@180
  1424
                  </li>
richt@180
  1425
richt@180
  1426
                  <li>
richt@180
  1427
                     Set <var>network service record</var>'s <code>url</code> property to the string value of the first occurrence of the <var>service</var>'s <code>controlURL</code> property.
richt@180
  1428
                  </li>
richt@180
  1429
richt@180
  1430
                  <li>
richt@180
  1431
                     Set <var>network service record</var>'s <code>config</code> property to the string value of the first occurrence of the <var>device</var> property.
richt@180
  1432
                  </li>
richt@180
  1433
richt@180
  1434
                  <li>
richt@180
  1435
                     If <var>service</var>'s <code>eventSubURL</code> property is empty, then continue to the step labeled <em>register</em> below.
richt@180
  1436
                  </li>
richt@180
  1437
richt@180
  1438
                  <li>
richt@180
  1439
                     Set <var>network service record</var>'s <code>eventsUrl</code> property to the string value of the first occurrence of the <var>service</var>'s <code>eventSubURL</code> property.
richt@180
  1440
                  </li>
richt@180
  1441
richt@180
  1442
                  <li>
richt@180
  1443
                     <em>Register</em>: For each Object <var>existing service record</var> in the current <a>list of available service records</a>, run the following sub-steps:
richt@180
  1444
                     <ol class="rule">
richt@180
  1445
richt@180
  1446
                       <li>
richt@180
  1447
                        If the <var>existing service record</var>'s <var>id</var> property matches the value of the first occurrence of <var>USN</var> and the
richt@180
  1448
                        <var>existing service record</var>'s <code>type</code> property matches the value of <var>network service record</var>'s <code>type</code>, then set the
richt@180
  1449
                        value of <var>existing service record</var> in the current <a>list of available service records</a>  to the value of the
richt@180
  1450
                        <var>network service record</var> and skip the next step.
richt@180
  1451
                       </li>
richt@180
  1452
                     </ol>
richt@180
  1453
                  </li>
richt@180
  1454
richt@180
  1455
                  <li>
richt@180
  1456
                     Add <var>network service record</var> to the <a>list of available service records</a>.
richt@180
  1457
                  </li>
richt@180
  1458
richt@180
  1459
               </ol>
richt@180
  1460
            </li>
richt@180
  1461
            <li>
richt@180
  1462
               <em>Update Service Monitor</em>: For each non-garbage collected <a href="#networkservice"><code>NetworkService</code></a> object run the following steps:
richt@180
  1463
richt@180
  1464
               <ol class="rule">
richt@180
  1465
                  <li>
richt@180
  1466
                     If this <a href="#networkservice"><code>NetworkService</code></a> object's <code>type</code> attribute does not equal the
richt@180
  1467
                     current <a>network service record</a>'s <code>type</code> property then continue at the next available active
richt@180
  1468
                     <a href="#networkservice"><code>NetworkService</code></a> object.
richt@180
  1469
                  </li>
richt@180
  1470
                  <li>
richt@180
  1471
                     If the <var>announcement type</var> equals <code>ssdp:alive</code> then Increment the <code>servicesAvailable</code> attribute of the <a href="#networkservices"><code>NetworkServices</code></a>
richt@180
  1472
                     object by <code>1</code>. Otherwise, decrement the <code>servicesAvailable</code> attribute of the <a href="#networkservices"><code>NetworkServices</code></a>
richt@180
  1473
                     object by <code>1</code>.
richt@180
  1474
                  </li>
richt@180
  1475
               </ol>
richt@180
  1476
            </li>
richt@180
  1477
         </ol>
richt@180
  1478
richt@180
  1479
         <p>
richt@180
  1480
            A <dfn>user-agent generated callback url</dfn> is a Local-network accessible URL endpoint that a <a>user agent</a> must generate and maintain for receiving HTTP NOTIFY requests from UPnP Event sources.
richt@180
  1481
         </p>
richt@180
  1482
richt@180
  1483
         <p>When the <a>user agent</a> is to <dfn>setup a UPnP Events Subscription</dfn>, it is to run the following steps with the current <var>network service record</var> object:</p>
richt@180
  1484
richt@180
  1485
         <ol class="rule">
richt@180
  1486
            <li>
richt@180
  1487
               If <var>network service record</var>'s <code>eventsUrl</code> property is empty then the <a>user agent</a> MUST abort these steps.
richt@180
  1488
            </li>
richt@180
  1489
richt@180
  1490
            <li>
richt@180
  1491
               Let <var>callback URL</var> be the value of creating a new <a>user-agent generated callback url</a>.
richt@180
  1492
            </li>
richt@180
  1493
richt@180
  1494
            <li>
richt@180
  1495
               Send a HTTP SUBSCRIBE request with a <em>NT</em> header with a string value of <code>upnp:event</code>, a <em>TIMEOUT</em> header with an integer value of
richt@180
  1496
               <code>86400</code> and a <em>CALLBACK</em> header
richt@180
  1497
               with a string value of <var>callback URL</var> towards the <var>network service record</var>'s <code>eventsUrl</code> property.
richt@180
  1498
            </li>
richt@180
  1499
richt@180
  1500
            <li>
richt@180
  1501
               If a non-200 OK response is received from the HTTP SUBSCRIBE request then the <a>user agent</a> MUST abort these steps.
richt@180
  1502
            </li>
richt@180
  1503
richt@180
  1504
            <li>
richt@180
  1505
               On receiving a valid 200 OK response, run the following steps:
richt@180
  1506
richt@180
  1507
               <ol class="rule">
richt@180
  1508
                  <li>
richt@180
  1509
                     Let <var>callback ID</var> equal the string value of the first included <em>SID</em> header, if it exists.
richt@180
  1510
                  </li>
richt@180
  1511
                  <li>
richt@180
  1512
                     Let <var>timeout date</var> equal the sum of the current UTC date value plus the integer value of the first included <em>TIMEOUT</em> header, if it exists.
richt@180
  1513
                  </li>
richt@180
  1514
                  <li>
richt@180
  1515
                     Run the following steps aynchronously and continue to the step labeled <em>listen</em> below.
richt@180
  1516
                  </li>
richt@180
  1517
                  <li>
richt@180
  1518
                     <em>Refresh Subscription</em>: Run the following steps at a set interval (X) within the <a>user agent</a>:
richt@180
  1519
richt@180
  1520
                     <ol class="rule">
richt@180
  1521
                        <li>
richt@180
  1522
                           Let <var>current date</var> equal the current UTC date.
richt@180
  1523
                        </li>
richt@180
  1524
                        <li>
richt@180
  1525
                           If <var>current date</var> is less than the <var>timeout date</var> then continue to the step labeled <em>refresh subscription</em> above.
richt@180
  1526
                        </li>
richt@180
  1527
                        <li>
richt@180
  1528
                           Send a HTTP SUBSCRIBE request with a <em>SID</em> header with the string value of <var>callback ID</var> and a <em>TIMEOUT</em> header
richt@180
  1529
                           with an integer value of <code>86400</code> towards the <var>network service record</var>'s <code>eventsUrl</code> property.
richt@180
  1530
                        </li>
richt@180
  1531
                        <li>
richt@180
  1532
                           On receiving a valid 200 OK, update <var>callback ID</var> with the string value of the first included <em>SID</em> header, if it exists. All other HTTP
richt@180
  1533
                           responses should cause the <a>user agent</a> to continue from the step labeled <em>refresh subscription</em> above.
richt@180
  1534
                        </li>
richt@180
  1535
                     </ol>
richt@180
  1536
richt@180
  1537
                  </li>
richt@180
  1538
richt@180
  1539
                  <li>
richt@180
  1540
                     <em>Listen</em>: For each HTTP NOTIFY request received at the <var>callback URL</var> the <a>user agent</a> is to run the following steps:
richt@180
  1541
richt@180
  1542
                     <ol class="rule">
richt@180
  1543
                        <li>
richt@180
  1544
                           Let <var>content clone</var> be the result of obtaining the message body of the HTTP NOTIFY request. If <var>content clone</var> is empty, then the <a>user agent</a> MUST abort these steps.
richt@180
  1545
                        </li>
richt@180
  1546
                        <li>
richt@180
  1547
                          Create a new <code>message</code> event that uses the <a href="http://dev.w3.org/html5/postmsg/#messageevent" class="externalDFN"><code>MessageEvent</code></a> interface [[!WEBMESSAGING]], with the name <code>message</code>,
richt@180
  1548
                           which does not bubble, is not cancelable, and has no default action.
richt@180
  1549
                        </li>
richt@180
  1550
                        <li>
richt@180
  1551
                           Let the <code>data</code> attribute of the event have the DOMString value of <var>content clone</var>.
richt@180
  1552
                        </li>
richt@180
  1553
                        <li>
richt@180
  1554
                           <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">Queue a task</a> to
richt@180
  1555
                            dispatch the newly created event at the current <a><code>NetworkService</code></a> object.
richt@180
  1556
                        </li>
richt@180
  1557
                     </ol>
richt@180
  1558
                  </li>
richt@180
  1559
richt@180
  1560
               </ol>
richt@180
  1561
richt@180
  1562
            </li>
richt@180
  1563
         </ol>
richt@180
  1564
richt@180
  1565
         </section>
richt@180
  1566
richt@180
  1567
         <section>
richt@180
  1568
            <h3>Network Topology Monitoring</h3>
richt@180
  1569
richt@180
  1570
                  <div>
richt@180
  1571
                     <p>
richt@180
  1572
                        When the <a>user agent</a> detects that the user has dropped from their connected network, then it MUST run the following steps:
richt@180
  1573
                     </p>
richt@180
  1574
richt@180
  1575
                     <ol class="rule">
richt@180
  1576
                        <li>
richt@180
  1577
                           Flush all entries from the <a>list of available service records</a>.
richt@180
  1578
                        </li>
richt@180
  1579
                        <li>
richt@180
  1580
                           For each <a href="#networkservice"><code>NetworkService</code></a> object currently active in the <a>user agent</a> perform the following steps:
richt@180
  1581
richt@180
  1582
                           <ol class="rule">
richt@180
  1583
                              <li>
richt@180
  1584
                                 Set the <a href="#dom-networkservice-readystate"><code>readyState</code></a> attribute to <code>2</code> (<a href="#dom-networkservice-UNAVAILABLE"><code>UNAVAILABLE</code></a>).
richt@180
  1585
                              </li>
richt@180
  1586
                              <li>
richt@180
  1587
                                 Create a new <code>readystatechange</code> event that uses the <code>Event</code> interface which does not bubble, is not cancelable, and has no default action.
richt@180
  1588
                              </li>
richt@180
  1589
                              <li>
richt@180
  1590
                                 <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task" class="externalDFN">Queue a task</a> to
richt@180
  1591
                                        dispatch the newly created event at the <a href="#networkservice"><code>NetworkService</code></a> object.
richt@180
  1592
                              </li>
richt@180
  1593
                           </ol>
richt@180
  1594
                        </li>
richt@180
  1595
                     </ol>
richt@180
  1596
richt@180
  1597
                     <p>
richt@180
  1598
                        When the <a>user agent</a> detects that the user has connected to a new network, then it SHOULD run the following steps:
richt@180
  1599
                     </p>
richt@180
  1600
richt@180
  1601
                     <ol class="rule">
richt@180
  1602
                        <li>
richt@180
  1603
                           Re-issue an mDNS search and SSDP discovery search and handle the responses according to the processing defined in <a href="#service-discovery">Section 6: Service Discovery</a>.
richt@180
  1604
                        </li>
richt@180
  1605
                     </ol>
richt@180
  1606
                  </div>
richt@180
  1607
         </section>
richt@180
  1608
      </section>
richt@180
  1609
richt@180
  1610
   <section>
richt@180
  1611
      <h3>Garbage collection</h3>
richt@180
  1612
richt@180
  1613
      <p>
richt@180
  1614
         A <a><code>NetworkService</code></a> object containing a <code>url</code> parameter currently in the <a>entry script origin's URL whitelist</a> MUST NOT be garbage collected.
richt@180
  1615
      </p>
richt@180
  1616
richt@180
  1617
      <p>
richt@180
  1618
         Only when the user navigates away from the current browsing context can <a><code>NetworkService</code></a> objects be garbage-collected and records in the <a>entry script origin's URL whitelist</a> be removed.
richt@180
  1619
      </p>
richt@180
  1620
richt@180
  1621
   </section>
richt@180
  1622
richt@180
  1623
richt@180
  1624
    <section>
richt@180
  1625
      <h3>Use Cases and Requirements</h3>
richt@180
  1626
richt@180
  1627
      <p>This section covers what the requirements are for this API, as well as illustrates some use cases.</p>
richt@180
  1628
richt@180
  1629
      <ul class="rule">
richt@180
  1630
         <li>
richt@180
  1631
            Once a user has given permission, user agents should provide the ability for Web pages to communicate directly with a Local-networked Service.
richt@180
  1632
            <ul class="rule">
richt@180
  1633
               <li>
richt@180
  1634
                  Example: A web-based TV remote control. A Web page wants to control the current user's TV, changing the programming shown or increasing/decreasing/muting the
richt@180
  1635
                  volume of the Local-networked Device. The Web page requests a service type that is known to be implemented by television sets to which it has the
richt@180
  1636
                  application logic to communicate. Local devices providing the request service types are discovered and presented to the user for authorization. The user selects one
richt@180
  1637
                  or more of the discovered television sets to be accessible to the current Web page and then clicks 'Share'. The Web page can now communicate directly with
richt@180
  1638
                  the user-authorized Local-networked services.
richt@180
  1639
               </li>
richt@180
  1640
            </ul>
richt@180
  1641
         </li>
richt@180
  1642
richt@180
  1643
         <li>
richt@180
  1644
           Web pages should be able to communicate with Local-networked Services using the messaging channel supported by those Devices.
richt@180
  1645
           <ul class="rule">
richt@180
  1646
            <li>
richt@180
  1647
               Example: A Web page advertises that it is capable of controlling multiple Home Media Servers. The user can select their Home Media Server type from a drop-down list, at which point the
richt@180
  1648
               Web page sends a request to the user agent to connect with the associated service type of the Home Media Server. The Media Server selected implements a Web Socket channel for
richt@180
  1649
               bi-directional service communication and so the Web page opens a web socket to the requested Media Server and can communicate as required via that appropriate channel.
richt@180
  1650
            </li>
richt@180
  1651
           </ul>
richt@180
  1652
         </li>
richt@180
  1653
richt@180
  1654
         <li>
richt@180
  1655
           Web pages should be able to communicate with Local-networked Services using the messaging format supported by those Devices.
richt@180
  1656
           <ul class="rule">
richt@180
  1657
            <li>
richt@180
  1658
               Example: A Web page advertises that it is capable of interacting with and controlling multiple types of Home Media Server. The user can select their Home Media Server type from a drop-down list or known Media Servers, at which point the
richt@180
  1659
               Web page sends a request to the user agent to connect with the associated service type (and, optionally, the associated event type) of the Home Media Server. The communiciation protocols supported by Home Media Servers typically vary
richt@180
  1660
               between UPnP, JSON-RPC, Protocol Buffers or other messaging formats depending on the Home Media Server requested. The Web page is able to communicate with the user-selected Home Media
richt@180
  1661
               Server in the messaging format supported by that Device, which, in this example is a simple key/value pair text format.
richt@180
  1662
            </li>
richt@180
  1663
           </ul>
richt@180
  1664
         </li>
richt@180
  1665
richt@180
  1666
         <li>
richt@180
  1667
           Web pages should not be able to communicate with Local-networked Services that have not been authorized by the user thereby maintaining the user's privacy.
richt@180
  1668
           <ul class="rule">
richt@180
  1669
            <li>
richt@180
  1670
               Example: A Web page requests access to one type of Local-networked service. The user authorizes access to that particular service. Other services running on that same device, and on other devices
richt@180
  1671
               within the network, should not be accessible to the current Web page.
richt@180
  1672
            </li>
richt@180
  1673
           </ul>
richt@180
  1674
         </li>
richt@180
  1675
richt@180
  1676
         <li>
richt@180
  1677
           A user should be able to share one or more Local-networked Services based on a particular service type request from a Web page.
richt@180
  1678
           <ul class="rule">
richt@180
  1679
            <li>
richt@180
  1680
               Example: A Web page is capable of interacting with a specific profile of Local-networked Service. As such, it makes a request to the user agent to access those services, of which multiple matches
richt@180
  1681
               are found. The user is capable of selecting one or more of the discovered services to share with the Web page. The Web page can then implement a drag-and-drop interface for the user to drag specific
richt@180
  1682
               actions on to one or more of the authorized Local-networked Services.
richt@180
  1683
            </li>
richt@180
  1684
           </ul>
richt@180
  1685
         </li>
richt@180
  1686
richt@180
  1687
         <li>
richt@180
  1688
           User agents should provide an API exposed to script that exposes the features above. The user is notified by UI anytime interaction with Local-networked Services is requested, giving the user
richt@180
  1689
           full ability to cancel or abort the transaction. The user selects the Local-networked Services to be connected to the current Web page, and can cancel these at any time. No invocations to
richt@180
  1690
           these APIs occur silently without user intervention.
richt@180
  1691
         </li>
richt@180
  1692
      </ul>
richt@180
  1693
    </section>
richt@180
  1694
richt@180
  1695
          <section class="informative appendix">
richt@180
  1696
             <h3>Examples</h3>
richt@180
  1697
richt@180
  1698
           <div class="example">
richt@180
  1699
            <p>This sample code exposes a button. When clicked, this button is disabled and the user is prompted to offer a network service. The user may also select multiple network services. When the user has authorized a network service to be connected to the web page then the web page issues a simple command to get a list of all the albums stored on the connected media player service.
richt@180
  1700
            <p>The button is re-enabled only when the connected network service disconnects for whatever reason (the service becomes unavailable on the network, the user disconnects from their current network or the user revokes access to the service from the current web page). At this point the user can re-click the button to select a new network service to connect to the web page and the above steps are repeated.</p>
richt@180
  1701
            <p>The provided service type identifier and service interaction used in this example is based on the well-defined service type and messaging format supported by the <a href="http://xbmc.org/about/">XBMC Media Server</a>. </p>
richt@180
  1702
            <hr />
richt@180
  1703
            <pre class="brush:js">&lt;input type="button" value="Start" onclick="start()" id="startBtn"/&gt;
richt@180
  1704
&lt;div id="debugconsole">&lt;/div>
richt@180
  1705
richt@180
  1706
&lt;script>
richt@180
  1707
 var startBtn = document.getElementById('startBtn'),
richt@180
  1708
     debug = document.getElementById('debugconsole');
richt@180
  1709
richt@180
  1710
 function start() {
richt@180
  1711
   if(navigator.getNetworkServices) {
richt@180
  1712
      navigator.getNetworkServices('zeroconf:_xbmc-jsonrpc._tcp', gotXBMCService, error);
richt@180
  1713
      startBtn.disabled = true;
richt@180
  1714
   } else {
richt@180
  1715
      debug.innerHTML += "&lt;br&gt;Service Discovery API not supported!";
richt@180
  1716
   }
richt@180
  1717
 }
richt@180
  1718
richt@180
  1719
 function gotXBMCService(services) {
richt@180
  1720
richt@180
  1721
// Listen for service disconnect messages
richt@180
  1722
richt@180
  1723
   services[0].addEventListener('readystatechange', function ( e ) {
richt@180
  1724
     if(services[0].readyState === services[0].UNAVAILABLE) {
richt@180
  1725
       debug.innerHTML += "&lt;br>" + services[0].name + " disconnected.";
richt@180
  1726
       startBtn.disabled = false;
richt@180
  1727
     }
richt@180
  1728
   }, false);
richt@180
  1729
richt@180
  1730
// Send a service message to get albums list (and process the service response)
richt@180
  1731
richt@180
  1732
   var svcXhr = new XMLHttpRequest();
richt@180
  1733
   svcXhr.open("POST", services[0].url + "/getAlbums"); // services[0].url and its subresources have been
richt@180
  1734
                                                        // whitelisted for cross-site XHR use in this
richt@180
  1735
                                                        // current browsing context.
richt@180
  1736
richt@180
  1737
   svcXhr.setRequestHeader('Content-Type', 'application/json-rpc');
richt@180
  1738
richt@180
  1739
   svcXhr.addEventListener('readystatechange', function ( response ) {
richt@180
  1740
     if( response.readyState != 4 || response.status != 200 )
richt@180
  1741
        return;
richt@180
  1742
     debug.innerHTML += "&lt;br>" + services[0].name + " response received: ";
richt@180
  1743
     debug.textContent += JSON.parse(response.responseText);
richt@180
  1744
   }, false);
richt@180
  1745
richt@180
  1746
   var svcMsg = [
richt@180
  1747
     { "jsonrpc": "2.0", "method": "AudioLibrary.GetAlbums", "params": { "genreid": -1,
richt@180
  1748
         "artistid": -1, "start": -1, "end": -1 }, "id": "1" }
richt@180
  1749
   ];
richt@180
  1750
richt@180
  1751
   svcXhr.send(JSON.stringify(svcMsg));
richt@180
  1752
   debug.innerHTML += "&lt;br>" + services[0].name + " request sent: ";
richt@180
  1753
   debug.textContent += JSON.stringify(svcMsg);
richt@180
  1754
richt@180
  1755
 }
richt@180
  1756
richt@180
  1757
 function error( err ) {
richt@180
  1758
   debug.innerHTML += "&lt;br>An error occurred obtaining a local network service.";
richt@180
  1759
   startBtn.disabled = false;
richt@180
  1760
 }
richt@180
  1761
&lt;/script></pre>
richt@180
  1762
           </div>
richt@180
  1763
richt@180
  1764
           <div class="example">
richt@180
  1765
            <p>
richt@180
  1766
             This sample exposes a drop-down list containing a number of common Home-based audio devices. When the user selects an audio device from the list provided, they are prompted to authorize a network service
richt@180
  1767
             based on the service type requested. The user may also select multiple network services matching the selected service type.
richt@180
  1768
             In this example, the user selects their make as being <var>Sony</var> and their model as being <var>Bravia S1000</var> from which the Web page can derive a service type
richt@180
  1769
             (<var>urn:schemas-upnp-org:service:RenderingControl:1</var>).
richt@180
  1770
             <br /><br />Once the user has authorized the device, the web page sends a simple mute command according to the messaging format supported by the device.
richt@180
  1771
            </p>
richt@180
  1772
            <hr />
richt@180
  1773
            <pre class="brush:js">&lt;select name="make" id="make"&gt;
richt@180
  1774
  &lt;option selected="selected" disabled="disabled"&gt;Select make&lt;/option&gt;
richt@180
  1775
  &lt;option&gt;Sony&lt;/option&gt;
richt@180
  1776
  &lt;option&gt;Philips&lt;/option&gt;
richt@180
  1777
  &lt;option&gt;Alba&lt;/option&gt;
richt@180
  1778
&lt;/select&gt;
richt@180
  1779
&lt;select name="model" id="model"&gt;&lt;/select&gt;
richt@180
  1780
&lt;div id="debugconsole"&gt;&lt;/div&gt;
richt@180
  1781
richt@180
  1782
&lt;script&gt;
richt@180
  1783
  var debug = document.getElementById('debugconsole');
richt@180
  1784
richt@180
  1785
  var models = {
richt@180
  1786
    "Sony": [
richt@180
  1787
      {"name": "Bravia TV S1000", "type": "upnp", "service": "urn:schemas-upnp-org:service:RenderingControl:1" },
richt@180
  1788
      {"name": "Bravia TV S2000", "type": "zeroconf", "service": "_mediarenderer._http._tcp" },
richt@180
  1789
      {"name": "HiFi WD10", "type": "upnp", "service": "urn:schemas-upnp-org:service:RenderingControl:1" }
richt@180
  1790
    ],
richt@180
  1791
    "Philips": [ /* ... */ ],
richt@180
  1792
    "Alba": [ /* ... */ ]
richt@180
  1793
  };
richt@180
  1794
richt@180
  1795
  var makeEl = document.getElementById("make"),
richt@180
  1796
      modelEl = document.getElementById("model");
richt@180
  1797
richt@180
  1798
  makeEl.addEventListener('change', function() {
richt@180
  1799
    modelEl.innerHTML = ""; // reset
richt@180
  1800
    var defaultOption = document.createElement("option");
richt@180
  1801
    defaultOption.textContent = "Select model";
richt@180
  1802
    defaultOption.setAttribute("disabled", "disabled");
richt@180
  1803
    defaultOption.setAttribute("selected", "selected");
richt@180
  1804
    modelEl.appendChild(defaultOption);
richt@180
  1805
    for(var i = 0, l = models[makeEl.value].length; i < l; i++) {
richt@180
  1806
      var option = document.createElement("option");
richt@180
  1807
      option.textContent = models[makeEl.value][i]["name"];
richt@180
  1808
      option.setAttribute("value", models[makeEl.value][i]["type"] + ":" + models[makeEl.value][i]["service"]);
richt@180
  1809
      modelEl.appendChild(option);
richt@180
  1810
    }
richt@180
  1811
  }, false);
richt@180
  1812
richt@180
  1813
  modelEl.addEventListener('change', function() {
richt@180
  1814
    if(navigator.getNetworkServices &&
richt@180
  1815
         modelEl.value == "upnp:urn:schemas-upnp-org:service:RenderingControl:1") {
richt@180
  1816
      navigator.getNetworkServices(modelEl.value, successCallback, errorCallback);
richt@180
  1817
    } else if (modelEl.value == "zeroconf:_mediarenderer._http._tcp") {
richt@180
  1818
      debug.innerHTML += "&lt;br&gt;Service type is not implemented by this application.";
richt@180
  1819
    } else {
richt@180
  1820
      debug.innerHTML += "&lt;br&gt;Service Discovery is not supported!";
richt@180
  1821
    }
richt@180
  1822
  }, false);
richt@180
  1823
&lt;/script&gt;
richt@180
  1824
richt@180
  1825
&lt;script&gt;
richt@180
  1826
  function successCallback( services ) {
richt@180
  1827
richt@180
  1828
  // Listen for service push messages
richt@180
  1829
richt@180
  1830
    services[0].addEventListener('message', function ( msg ) {
richt@180
  1831
         debug.innerHTML += "&lt;br>" + services[0].name + " event received: ";
richt@180
  1832
         debug.textContent += msg.data;
richt@180
  1833
    }, false);
richt@180
  1834
richt@180
  1835
 // Send a control signal to mute the service audio
richt@180
  1836
richt@180
  1837
    var svcXhr = new XMLHttpRequest();
richt@180
  1838
    svcXhr.open("POST", services[0].url); // services[0].url and its
richt@180
  1839
                                          // subresources have been whitelisted for
richt@180
  1840
                                          // cross-site XHR use in this current
richt@180
  1841
                                          // browsing context.
richt@180
  1842
richt@180
  1843
    svcXhr.setRequestHeader('SOAPAction', 'urn:schemas-upnp-org:service:RenderingControl:1#SetMute');
richt@180
  1844
    svcXhr.setRequestHeader('Content-Type', 'text/xml; charset="utf-8";');
richt@180
  1845
richt@180
  1846
    svcXhr.onreadystatechange = function ( response ) {
richt@180
  1847
      if( response.readyState != 4 || response.status != 200 )
richt@180
  1848
        return;
richt@180
  1849
      debug.innerHTML += "&lt;br&gt;" + services[0].name + " response received: ";
richt@180
  1850
      debug.textContent += response.responseXML;
richt@180
  1851
    }
richt@180
  1852
richt@180
  1853
    // Service messaging to mute the provided service
richt@180
  1854
    var svcMsg = '&lt;?xml version="1.0" encoding="utf-8"?&gt;' +
richt@180
  1855
                 '&lt;s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" ' +
richt@180
  1856
                   'xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"&gt;' +
richt@180
  1857
                   '&lt;s:Body&gt;' +
richt@180
  1858
                     '&lt;u:SetMute xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1"&gt;' +
richt@180
  1859
                       '&lt;InstanceID&gt;0&lt;/InstanceID&gt;' +
richt@180
  1860
                       '&lt;Channel&gt;Master&lt;/Channel&gt;' +
richt@180
  1861
                       '&lt;DesiredMute&gt;true&lt;/DesiredMute&gt;' +
richt@180
  1862
                     '&lt;/u:SetMute&gt;' +
richt@180
  1863
                   '&lt;/s:Body&gt;' +
richt@180
  1864
                 '&lt;/s:Envelope&gt;';
richt@180
  1865
richt@180
  1866
    svcXhr.send(svcMsg);
richt@180
  1867
    debug.innerHTML += "&lt;br&gt;" + services[0].name + " request sent: ";
richt@180
  1868
    debug.textContent += svcMsg;
richt@180
  1869
  }
richt@180
  1870
richt@180
  1871
  function errorCallback( error ) {
richt@180
  1872
    debug.innerHTML += "&lt;br&gt;An error occurred: " + error.code;
richt@180
  1873
  }
richt@180
  1874
&lt;/script&gt;</pre>
richt@180
  1875
          </div>
richt@180
  1876
richt@180
  1877
       </section>
richt@180
  1878
richt@180
  1879
    <section>
richt@180
  1880
      <h3>Acknowledgements</h3>
richt@180
  1881
richt@180
  1882
      <p>Thanks are expressed by the editor to the following individuals for their feedback on this specification to date (in alphabetical order):
richt@180
  1883
      <br /><br />
richt@180
  1884
      Gar Bergstedt, Lars-Erik Bolstad, Hari G Kumar, Bob Lund, Giuseppe Pascale, Marcin Simonides, Clarke Stevens, Christian S&ouml;derstr&ouml;m, Mark Vickers, ...</p>
richt@180
  1885
richt@180
  1886
      <p>Thanks are also expressed by the editor to the following organizations and groups for their support in producing this specification to date (in alphabetical order):
richt@180
  1887
      <br /></br />
richt@180
  1888
      CableLabs, Opera Software ASA, W3C Device APIs Working Group, W3C Web and TV Interest Group, ...</p>
richt@180
  1889
    </section>
richt@180
  1890
richt@180
  1891
    <script class='remove'>
richt@180
  1892
    if(SyntaxHighlighter) {
richt@180
  1893
      SyntaxHighlighter.defaults['gutter'] = false;
richt@180
  1894
      SyntaxHighlighter.defaults['toolbar'] = false;
richt@180
  1895
      SyntaxHighlighter.all()
richt@180
  1896
    }
richt@180
  1897
    </script>
richt@180
  1898
richt@180
  1899
</body>
richt@180
  1900
</html>