webrtc/RTCPeerConnection-ondatachannel.html

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<title>RTCPeerConnection.prototype.ondatachannel</title>
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'use strict';

// Test is based on the following revision:
// https://rawgit.com/w3c/webrtc-pc/1cc5bfc3ff18741033d804c4a71f7891242fb5b3/webrtc.html

// The following helper functions are called from RTCPeerConnection-helper.js:
// exchangeIceCandidates
// exchangeOfferAnswer
// createDataChannelPair

/*
  6.2.  RTCDataChannel
    When an underlying data transport is to be announced (the other peer created a channel with
    negotiated unset or set to false), the user agent of the peer that did not initiate the
    creation process MUST queue a task to run the following steps:
      2. Let channel be a newly created RTCDataChannel object.
      7. Set channel's [[ReadyState]] to open (but do not fire the open event, yet).
      8. Fire a datachannel event named datachannel with channel at the RTCPeerConnection object.

  6.3.  RTCDataChannelEvent
    Firing a datachannel event named e with an RTCDataChannel channel means that an event with the
    name e, which does not bubble (except where otherwise stated) and is not cancelable (except
    where otherwise stated), and which uses the RTCDataChannelEvent interface with the channel
    attribute set to channel, MUST be created and dispatched at the given target.

    interface RTCDataChannelEvent : Event {
      readonly attribute RTCDataChannel channel;
    };
 */
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  let eventCount = 0;

  pc2.ondatachannel = t.step_func((event) => {
    eventCount++;
    assert_equals(eventCount, 1,
      'Expect data channel event to fire exactly once');

    assert_true(event instanceof RTCDataChannelEvent,
      'Expect event to be instance of RTCDataChannelEvent');

    assert_equals(event.bubbles, false);
    assert_equals(event.cancelable, false);

    const dc = event.channel;
    assert_true(dc instanceof RTCDataChannel,
      'Expect channel to be instance of RTCDataChannel');

    // The channel should be in the 'open' state already.
    // See: https://github.com/w3c/webrtc-pc/pull/1851
    assert_equals(dc.readyState, 'open',
      'Expect channel ready state to be open');

    resolver.resolve();
  });

  pc1.createDataChannel('fire-me!');

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'Data channel event should fire when new data channel is announced to the remote peer');

/*
  Since the channel should be in the 'open' state when dispatching via the 'datachannel' event,
  we should be able to send data in the event handler.
 */
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  const message = 'meow meow!';

  pc2.ondatachannel = t.step_func((event) => {
    const dc2 = event.channel;
    dc2.send(message);
  });

  const dc1 = pc1.createDataChannel('fire-me!');
  dc1.onmessage = t.step_func((event) => {
    assert_equals(event.data, message,
      'Received data should be equal to sent data');

    resolver.resolve();
  });

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'Should be able to send data in a datachannel event handler');

/*
  6.2.  RTCDataChannel
    When an underlying data transport is to be announced (the other peer created a channel with
    negotiated unset or set to false), the user agent of the peer that did not initiate the
    creation process MUST queue a task to run the following steps:
      8. Fire a datachannel event named datachannel with channel at the RTCPeerConnection object.
      9. If the channel's [[ReadyState]] is still open, announce the data channel as open.
 */
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  pc2.ondatachannel = t.step_func((event) => {
    const dc = event.channel;
    dc.onopen = t.step_func(() => {
      assert_unreached('Open event should not fire');
    });

    // This should prevent triggering the 'open' event
    dc.close();

    // Wait a bit to ensure the 'open' event does NOT fire
    t.step_timeout(() => resolver.resolve(), 500);
  });

  pc1.createDataChannel('fire-me!');

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'Open event should not be raised when closing the channel in the datachannel event');

// Added this test as a result of the discussion in
// https://github.com/w3c/webrtc-pc/pull/1851#discussion_r185976747
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  pc2.ondatachannel = t.step_func((event) => {
    const dc = event.channel;
    dc.onopen = t.step_func((event) => {
      resolver.resolve();
    });

    // This should NOT prevent triggering the 'open' event since it enqueues at least two tasks
    t.step_timeout(() => {
      t.step_timeout(() => {
        dc.close()
      }, 1);
    }, 1);
  });

  pc1.createDataChannel('fire-me!');

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'Open event should be raised when closing the channel in the datachannel event after ' +
  'enqueuing a task');


/*
  Combination of the two tests above (send and close).
 */
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  const message = 'meow meow!';

  pc2.ondatachannel = t.step_func((event) => {
    const dc2 = event.channel;
    dc2.onopen = t.step_func(() => {
      assert_unreached('Open event should not fire');
    });

    // This should send but still prevent triggering the 'open' event
    dc2.send(message);
    dc2.close();
  });

  const dc1 = pc1.createDataChannel('fire-me!');
  dc1.onmessage = t.step_func((event) => {
    assert_equals(event.data, message,
      'Received data should be equal to sent data');

    resolver.resolve();
  });

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'Open event should not be raised when sending and immediately closing the channel in the ' +
  'datachannel event');

/*
  6.2.  RTCDataChannel

    interface RTCDataChannel : EventTarget {
      readonly attribute USVString           label;
      readonly attribute boolean             ordered;
      readonly attribute unsigned short?     maxPacketLifeTime;
      readonly attribute unsigned short?     maxRetransmits;
      readonly attribute USVString           protocol;
      readonly attribute boolean             negotiated;
      readonly attribute unsigned short?     id;
      readonly attribute RTCDataChannelState readyState;
      ...
    };

    When an underlying data transport is to be announced (the other peer created a channel with
    negotiated unset or set to false), the user agent of the peer that did not initiate the
    creation process MUST queue a task to run the following steps:
      2. Let channel be a newly created RTCDataChannel object.
      3. Let configuration be an information bundle received from the other peer as a part of the
         process to establish the underlying data transport described by the WebRTC DataChannel
         Protocol specification [RTCWEB-DATA-PROTOCOL].
      4. Initialize channel's [[DataChannelLabel]], [[Ordered]], [[MaxPacketLifeTime]],
         [[MaxRetransmits]], [[DataChannelProtocol]], and [[DataChannelId]] internal slots to the
         corresponding values in configuration.
      5. Initialize channel's [[Negotiated]] internal slot to false.
      7. Set channel's [[ReadyState]] slot to connecting.
      8. Fire a datachannel event named datachannel with channel at the RTCPeerConnection object.

    Note: More exhaustive tests are defined in RTCDataChannel-dcep
 */

promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  const dc1 = pc1.createDataChannel('test', {
    ordered: false,
    maxRetransmits: 1,
    protocol: 'custom'
  });

  assert_equals(dc1.label, 'test');
  assert_equals(dc1.ordered, false);
  assert_equals(dc1.maxPacketLifeTime, null);
  assert_equals(dc1.maxRetransmits, 1);
  assert_equals(dc1.protocol, 'custom');
  assert_equals(dc1.negotiated, false);

  pc2.ondatachannel = t.step_func((event) => {
    const dc2 = event.channel;
    assert_true(dc2 instanceof RTCDataChannel,
      'Expect channel to be instance of RTCDataChannel');

    assert_equals(dc2.label, 'test');
    assert_equals(dc2.ordered, false);
    assert_equals(dc2.maxPacketLifeTime, null);
    assert_equals(dc2.maxRetransmits, 1);
    assert_equals(dc2.protocol, 'custom');
    assert_equals(dc2.negotiated, false);
    assert_equals(dc2.id, dc1.id);

    resolver.resolve();
  });

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'In-band negotiated channel created on remote peer should match the same configuration as local ' +
  'peer');

promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  const dc1 = pc1.createDataChannel('');

  assert_equals(dc1.label, '');
  assert_equals(dc1.ordered, true);
  assert_equals(dc1.maxPacketLifeTime, null);
  assert_equals(dc1.maxRetransmits, null);
  assert_equals(dc1.protocol, '');
  assert_equals(dc1.negotiated, false);

  pc2.ondatachannel = t.step_func((event) => {
    const dc2 = event.channel;
    assert_true(dc2 instanceof RTCDataChannel,
      'Expect channel to be instance of RTCDataChannel');

    assert_equals(dc2.label, '');
    assert_equals(dc2.ordered, true);
    assert_equals(dc2.maxPacketLifeTime, null);
    assert_equals(dc2.maxRetransmits, null);
    assert_equals(dc2.protocol, '');
    assert_equals(dc2.negotiated, false);
    assert_equals(dc2.id, dc1.id);

    resolver.resolve();
  });

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  await resolver;
}, 'In-band negotiated channel created on remote peer should match the same (default) ' +
  'configuration as local peer');

/*
  6.2.  RTCDataChannel
    Dictionary RTCDataChannelInit Members
      negotiated
        The default value of false tells the user agent to announce the
        channel in-band and instruct the other peer to dispatch a corresponding
        RTCDataChannel object. If set to true, it is up to the application
        to negotiate the channel and create a RTCDataChannel object with the
        same id at the other peer.
 */
promise_test(async (t) => {
  const resolver = new Resolver();
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());

  pc2.ondatachannel = t.unreached_func('datachannel event should not be fired');

  pc1.createDataChannel('test', {
    negotiated: true,
    id: 42
  });

  exchangeIceCandidates(pc1, pc2);
  await exchangeOfferAnswer(pc1, pc2);

  // Wait a bit to ensure the 'datachannel' event does NOT fire
  t.step_timeout(() => resolver.resolve(), 500);
  await resolver;
}, 'Negotiated channel should not fire datachannel event on remote peer');

/*
  Non-testable
  6.2.  RTCDataChannel
    When an underlying data transport is to be announced
      1.  If the associated RTCPeerConnection object's [[isClosed]] slot
          is true, abort these steps.

  The above step is not testable because to reach it we would have to
  close the peer connection just between receiving the in-band negotiated data
  channel via DCEP and firing the datachannel event.
 */
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