live_stream.sjs - mozsearch

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// Serves a real MP3 fixture without ever revealing its total length, and

// keeps the HTTP response open for a while after writing all of its bytes.

// This mimics a live stream (e.g. internet radio), whose connection stays

// open during normal playback instead of completing like a regular

// finite-length download.

//

// Simply omitting `Content-Length` isn't enough on its own: Gecko also

// reclassifies a resource as finite-length once its download completes

// (see `ChannelMediaDecoder::NotifyDownloadEnded()`), which happens near-

// instantly for any small static file served locally. Holding the

// connection (for `HOLD_OPEN_MS`) open avoids that, matching how a real broadcast behaves.

//

// The fixture itself is a short (~1s) MP3 stream carrying its own `Info`

// header, immediately followed by a second, header-less MP3 stream. This

// mimics a short pre-recorded prelude in front of a live broadcast: the

// prelude's duration is known upfront, while the broadcast portion has no

// declared duration, so Gecko instead reports its playback position as the

// growing duration - matching a real live stream.

const HOLD_OPEN_MS = 2000;

function handleRequest(request, response) {

  var src = Services.dirsvc.get("CurWorkD", Ci.nsIFile);

  var split =

    "tests/dom/media/test/single-xing-header-no-content-length.mp3".split("/");

  for (var i = 0; i < split.length; ++i) {

    src.append(split[i]);

  var file = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(

    Ci.nsIFileInputStream

);

  file.init(src, -1, -1, false);

  var input = Cc["@mozilla.org/binaryinputstream;1"].createInstance(

    Ci.nsIBinaryInputStream

);

  input.setInputStream(file);

  var bytes = input.readBytes(input.available());

  input.close();

  response.setHeader("Content-Type", "audio/mpeg", false);

  response.setHeader("Cache-Control", "no-store", false);

  // Deliberately no Content-Length header.

  response.write(bytes, bytes.length);

  // Hold the connection for a while.

  response.processAsync();

  const Timer = Components.Constructor(

    "@mozilla.org/timer;1",

    "nsITimer",

    "initWithCallback"

);

  // eslint-disable-next-line no-unused-vars

  var timer = new Timer(

    function () {

      response.finish();

},

    HOLD_OPEN_MS,

    Ci.nsITimer.TYPE_ONE_SHOT

);