WebRTCPeerConnection

Inherits: Reference < Object

Inherited By: WebRTCPeerConnectionGDNative

Interface to a WebRTC peer connection.

Description

A WebRTC connection between the local computer and a remote peer. Provides an interface to connect, maintain and monitor the connection.

Setting up a WebRTC connection between two peers from now on) may not seem a trivial task, but it can be broken down into 3 main steps:

• The peer that wants to initiate the connection (A from now on) creates an offer and send it to the other peer (B from now on).
• B receives the offer, generate and answer, and sends it to A).
• A and B then generates and exchange ICE candidates with each other.

After these steps, the connection should become connected. Keep on reading or look into the tutorial for more information.

Methods

Signals

• data_channel_received ( Object channel )

Emitted when a new in-band channel is received, i.e. when the channel was created with negotiated: false (default).

The object will be an instance of WebRTCDataChannel. You must keep a reference of it or it will be closed automatically. See create_data_channel.

• ice_candidate_created ( String media, int index, String name )

Emitted when a new ICE candidate has been created. The three parameters are meant to be passed to the remote peer over the signaling server.

• session_description_created ( String type, String sdp )

Emitted after a successful call to create_offer or set_remote_description (when it generates an answer). The parameters are meant to be passed to set_local_description on this object, and sent to the remote peer over the signaling server.

Enumerations

enum ConnectionState:

• STATE_NEW = 0 —- The connection is new, data channels and an offer can be created in this state.
• STATE_CONNECTING = 1 —- The peer is connecting, ICE is in progress, none of the transports has failed.
• STATE_CONNECTED = 2 —- The peer is connected, all ICE transports are connected.
• STATE_DISCONNECTED = 3 —- At least one ICE transport is disconnected.
• STATE_FAILED = 4 —- One or more of the ICE transports failed.
• STATE_CLOSED = 5 —- The peer connection is closed (after calling close for example).

Method Descriptions

• Error add_ice_candidate ( String media, int index, String name )

Add an ice candidate generated by a remote peer (and received over the signaling server). See ice_candidate_created.

• void close ( )

Close the peer connection and all data channels associated with it. Note, you cannot reuse this object for a new connection unless you call initialize.

• WebRTCDataChannel create_data_channel ( String label, Dictionary options={ } )

Returns a new WebRTCDataChannel (or null on failure) with given label and optionally configured via the options dictionary. This method can only be called when the connection is in state STATE_NEW.

There are two ways to create a working data channel: either call create_data_channel on only one of the peer and listen to data_channel_received on the other, or call create_data_channel on both peers, with the same values, and the negotiated option set to true.

Valid options are:

{
    "negotiated": true, # When set to true (default off), means the channel is negotiated out of band. "id" must be set too. data_channel_received will not be called.
    "id": 1, # When "negotiated" is true this value must also be set to the same value on both peer.
    # Only one of maxRetransmits and maxPacketLifeTime can be specified, not both. They make the channel unreliable (but also better at real time).
    "maxRetransmits": 1, # Specify the maximum number of attempt the peer will make to retransmits packets if they are not acknowledged.
    "maxPacketLifeTime": 100, # Specify the maximum amount of time before giving up retransmitions of unacknowledged packets (in milliseconds).
    "ordered": true, # When in unreliable mode (i.e. either "maxRetransmits" or "maxPacketLifetime" is set), "ordered" (true by default) specify if packet ordering is to be enforced.
    "protocol": "my-custom-protocol", # A custom sub-protocol string for this channel.
}

Note: You must keep a reference to channels created this way, or it will be closed.

• Error create_offer ( )

Creates a new SDP offer to start a WebRTC connection with a remote peer. At least one WebRTCDataChannel must have been created before calling this method.

If this functions returns @GlobalScope.OK, session_description_created will be called when the session is ready to be sent.

• ConnectionState get_connection_state ( ) const

Returns the connection state. See ConnectionState.

• Error initialize ( Dictionary configuration={ } )

Re-initialize this peer connection, closing any previously active connection, and going back to state STATE_NEW. A dictionary of options can be passed to configure the peer connection.

Valid options are:

{
    "iceServers": [
        {
            "urls": [ "stun:stun.example.com:3478" ], # One or more STUN servers.
        },
        {
            "urls": [ "turn:turn.example.com:3478" ], # One or more TURN servers.
            "username": "a_username", # Optional username for the TURN server.
            "credential": "a_password", # Optional password for the TURN server.
        }
    ]
}

• Error poll ( )

Call this method frequently (e.g. in Node._process or Node._physics_process) to properly receive signals.

• Error set_local_description ( String type, String sdp )

Sets the SDP description of the local peer. This should be called in response to session_description_created.

After calling this function the peer will start emitting ice_candidate_created (unless an Error different from @GlobalScope.OK is returned).

• Error set_remote_description ( String type, String sdp )

Sets the SDP description of the remote peer. This should be called with the values generated by a remote peer and received over the signaling server.

If type is offer the peer will emit session_description_created with the appropriate answer.

If type is answer the peer will start emitting ice_candidate_created.