RTCSessionDescription - Web APIs 编辑

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The RTCSessionDescription interface describes one end of a connection—or potential connection—and how it's configured. Each RTCSessionDescription consists of a description type indicating which part of the offer/answer negotiation process it describes and of the SDP descriptor of the session.

The process of negotiating a connection between two peers involves exchanging RTCSessionDescription objects back and forth, with each description suggesting one combination of connection configuration options that the sender of the description supports. Once the two peers agree upon a configuration for the connection, negotiation is complete.

Properties

The RTCSessionDescription interface doesn't inherit any properties.

RTCSessionDescription.type Read only

An enum of type RTCSdpType describing the session description's type.

RTCSessionDescription.sdp Read only

A DOMString containing the SDP describing the session.

Constants

RTCSdpType

This enum defines strings that describe the current state of the session description, as used in the type property. The session description's type will be specified using one of these values.

Methods

The RTCSessionDescription doesn't inherit any methods.

RTCSessionDescription()

This constructor returns a new RTCSessionDescription. The parameter is a RTCSessionDescriptionInit dictionary containing the values to assign the two properties.

RTCSessionDescription.toJSON()

Returns a JSON description of the object. The values of both properties, type and sdp, are contained in the generated JSON.

Example 

signalingChannel.onmessage = function (evt) {
    if (!pc)
        start(false);

    var message = JSON.parse(evt.data);
    if (message.sdp)
        pc.setRemoteDescription(new RTCSessionDescription(message), function () {
            // if we received an offer, we need to answer
            if (pc.remoteDescription.type == "offer")
                pc.createAnswer(localDescCreated, logError);
        }, logError);
    else
        pc.addIceCandidate(new RTCIceCandidate(message.candidate),
            function () {}, logError);
};

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• WebRTC
• RTCPeerConnection.setLocalDescription() and RTCPeerConnection.setRemoteDescription()