RTCDataChannel

RTCDataChannel接口代表在两者之间建立了一个双向数据通道的连接。

可以用RTCDataChannel.createDataChannel()或者在现有的 RTCPeerConnection上用 RTCDataChannelEvent类型的 datachannel 事件接收，创建出 RTCDataChannel类型的对象。

属性

RTCDataChannel.label 只读

返回一个包含有描述数据通道名字的DOMString。这个字段没有唯一性要求。

RTCDataChannel.ordered 只读

返回一个Boolean对象，表示传递信息的顺序是否有保证。

RTCDataChannel.protocol 只读

返回一个包含有正在使用的子协议的名称的 DOMString，如果没有这样的子协议，返回""

RTCDataChannel.id 只读

当RTCDataChannel对象被创建出来的时候，返回一个无符号short类型的数据，作为通道的标识id。

RTCDataChannel.readyState 只读

返回枚举类型的 RTCDataChannelState，表示数据连接的状态，有以下几种类型：

• "connecting" is the state indicating that the underlying connection is not yet set up and active. This is the initial state of a data channel created with RTCPeerConnection.createDataChannel().
• "open" is the state indicating that the underlying connection is up and running. This is the initial state of a data channel dispatched in a RTCDataChannelEvent.
• "closing" is the state indicating that the underlying connection is in the process of shutting down. No new sending task is accepting but the cached messages are in the process of being sent, or received.
• "closed" is the state indicating that the underlying connection has been shut down (or couldn't be established).

RTCDataChannel.bufferedAmount 只读

Returns an unsigned long containing the amount of bytes that have been queued for sending: that is the amount of data requested to be transmitted via RTCDataChannel.send() that has not been sent yet. Note that if the channel is closed, the buffering continues.

RTCDataChannel.binaryType

Is a DOMString indicating the type of binary data transmitted by the connection. This should be either "blob" if Blob objects are being used or "arraybuffer" if ArrayBuffer objects are being used. Initially it is set to "blob".

RTCDataChannel.maxPacketLifeType 只读

Is an unsigned short indicating the length in milliseconds of the window in when messaging happens in unreliable mode.

RTCDataChannel.maxRetransmits 只读

Is an unsigned short indicating the maximum amount of retransmissions that can happen when messaging happens in unreliable mode.

RTCDataChannel.negotiated 只读

Is a Boolean indicating if the channel has been negotiated by the application, or not.

DataChannel.reliable 只读

Is a Boolean indicating if the connection can send message in unreliable mode.

DataChannel.stream 只读

Is an obsolete synonym for RTCDataChannel.id.

Event Handlers

RTCDataChannel.onopen

Is the event handler called when the open event is received. Such an event is sent when a the underlying data transport, that is the data connection, has been established.

RTCDataChannel.onmessage

Is the event handler called when the message event is received. Such an event is sent when a message is available on the data connection.

RTCDataChannel.onclose

Is the event handler called when the close event is received. Such an event is sent when the underlying data transport has been closed.

RTCDataChannel.onerror

Is the event handler called when the error event is received. Such an event is sent when an error has been encountered.

Methods

RTCDataChannel.close()

Closes the channel. The closing is done in a non abrupt way. The state of the channel is set to "closing", the messages not yet sent are sent, then the channel is closed.

RTCDataChannel.send()

Sends the data in parameter over the channel. The data can be a DOMString, a Blob, an ArrayBuffer or an ArrayBufferView.

Example

var pc = new RTCPeerConnection();
var dc = pc.createDataChannel("my channel");
dc.onmessage = function (event) {
  console.log("received: " + event.data);
};
dc.onopen = function () {
  console.log("datachannel open");
};
dc.onclose = function () {
  console.log("datachannel close");
};

Specifications

Browser compatibility

[1] The interface is called DataChannel and not RTCDataChannel

See also

• WebRTC