lib/signaling

Signaling client for the WebRTC transport.

Speaks the line protocol of the server's signaling WebSocket. HELLO <peer type> <json> registers the client, the JSON carrying its type, slot, strict-viewer flag, secure-mode token, display id, display position, tab, the start rate congestion control last held its display at, and the session's resume key; SESSION server asks for the server peer and is answered with SESSION_OK <peer id>; from then on the SDP and the ICE candidates travel as <peer id> {"sdp": ...} and <peer id> {"ice": ...} lines, and ERROR ... lines report server-side failures. The server always offers and the client answers.

A socket cut while the app's media still runs (resumable) reopens at once with the same resume key: the server, which holds a cut client's session for a few seconds, answers RESUMED <peer id> and the session carries on, the peer connection untouched (onresumed); a plain HELLO (the hold ran out, or a server that holds none) starts a new session as after any drop.

A failed or dropped connection retries RETRY_FIRST_MS later, each further failure twice as far out up to RETRY_MAX_MS; the fourth consecutive failure hands over to onfatalretry (or reloads the page) so the browser re-runs HTTP authentication.

ClassesCopy Anchor Link

WebRTCSignalingCopy Anchor Link

Defined in: lib/signaling.js:72

Connection to the signaling server, delivering SDP and ICE to callbacks.

Callbacks are assigned as properties: onstatus, ondebug, and onerror receive messages, onsdp an RTCSessionDescription, onice an RTCIceCandidate, ondisconnect whether the app should reconnect, onshowalert a reason to show the user, onfatalretry replaces the page reload after repeated failures, resumable says whether a cut socket's session is worth resuming, and onresumed follows a resume.

ConstructorsCopy Anchor Link

ConstructorCopy Anchor Link

new WebRTCSignaling(
   server, 
   client_type, 
   client_slot, 
   client_strict_viewer, 
   client_token, 
   display_id, 
   display_position
): WebRTCSignaling;

Defined in: lib/signaling.js:87

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

WebRTCSignaling

PropertiesCopy Anchor Link

capabilitiesCopy Anchor Link

capabilities: () => Promise<string[]>;

Defined in: lib/signaling.js:98

Answers, before the hello, which codec names this engine decodes at 4:4:4, so the server offers 4:2:0 to a client without them rather than a profile it paints nothing of; unset, the hello says nothing and the server takes the client at its word.

ReturnsCopy Anchor Link

Promise<string[]>

tenBitCapabilitiesCopy Anchor Link

tenBitCapabilities: () => Promise<string[]>;

Defined in: lib/signaling.js:107

Answers, before the hello, which formats this engine decodes at 10 bits, a codec name for 4:2:0 and the name with 444 after it for 4:4:4, so the server offers 8 bits to a client without them; unset, the hello says nothing.

ReturnsCopy Anchor Link

Promise<string[]>

pageSizeCopy Anchor Link

pageSize: () => number[];

Defined in: lib/signaling.js:114

Returns the [width, height] the page's first resize will ask for, which the server starts the primary's capture at, or null where the page sends none; unset, the hello says nothing.

ReturnsCopy Anchor Link

number[]

peer_idCopy Anchor Link

peer_id: number;

Defined in: lib/signaling.js:117

Local peer id, set by the WebRTC client before connect.

onstatusCopy Anchor Link

onstatus: (arg0) => void;

Defined in: lib/signaling.js:123

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

onfatalretryCopy Anchor Link

onfatalretry: () => void;

Defined in: lib/signaling.js:130

Called instead of the page reload after repeated connect failures, so the app may inspect the endpoint before reloading.

ReturnsCopy Anchor Link

void

onerrorCopy Anchor Link

onerror: (arg0) => void;

Defined in: lib/signaling.js:133

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

ondebugCopy Anchor Link

ondebug: (arg0) => void;

Defined in: lib/signaling.js:136

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

oniceCopy Anchor Link

onice: (arg0) => void;

Defined in: lib/signaling.js:139

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

onsdpCopy Anchor Link

onsdp: (arg0) => void;

Defined in: lib/signaling.js:142

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

ondisconnectCopy Anchor Link

ondisconnect: (arg0) => void;

Defined in: lib/signaling.js:145

Called with whether the app should reconnect.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

resumableCopy Anchor Link

resumable: () => boolean;

Defined in: lib/signaling.js:148

Whether the session of a cut socket is worth resuming (its media runs on).

ReturnsCopy Anchor Link

boolean

onresumedCopy Anchor Link

onresumed: () => void;

Defined in: lib/signaling.js:151

Called once the session of a cut socket carries on over a new one.

ReturnsCopy Anchor Link

void

resume_keyCopy Anchor Link

resume_key: string;

Defined in: lib/signaling.js:154

The key the hello names; a new session gets a new one.

stateCopy Anchor Link

state: string;

Defined in: lib/signaling.js:161

'disconnected', 'connecting', or 'connected'.

retry_countCopy Anchor Link

retry_count: number;

Defined in: lib/signaling.js:164

currResCopy Anchor Link

currRes: number[];

Defined in: lib/signaling.js:195

peer_typeCopy Anchor Link

peer_type: string;

Defined in: lib/signaling.js:198

client_typeCopy Anchor Link

client_type: string;

Defined in: lib/signaling.js:201

'viewer' or 'controller'.

server_peer_idCopy Anchor Link

server_peer_id: string;

Defined in: lib/signaling.js:204

client_slotCopy Anchor Link

client_slot: number;

Defined in: lib/signaling.js:207

client_strict_viewerCopy Anchor Link

client_strict_viewer: boolean;

Defined in: lib/signaling.js:210

client_tokenCopy Anchor Link

client_token: string;

Defined in: lib/signaling.js:213

display_idCopy Anchor Link

display_id: string;

Defined in: lib/signaling.js:216

display_positionCopy Anchor Link

display_position: string;

Defined in: lib/signaling.js:219

onshowalertCopy Anchor Link

onshowalert: (arg0) => void;

Defined in: lib/signaling.js:222

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

MethodsCopy Anchor Link

retry()Copy Anchor Link

retry(): void;

Defined in: lib/signaling.js:331

Starts the retry cycle over, for an app whose onfatalretry found the server not answering: the next connect on the delay the failures so far set, and the next cycle ending in onfatalretry again.

ReturnsCopy Anchor Link

void

connect()Copy Anchor Link

connect(): void;

Defined in: lib/signaling.js:472

Opens the signaling socket; registration, the session request, and the SDP and ICE exchange follow from the socket events.

ReturnsCopy Anchor Link

void

reconnect()Copy Anchor Link

reconnect(): void;

Defined in: lib/signaling.js:496

Starts a new session, under a new resume key, in place of one whose media path failed while this socket stayed up, or one whose hold on the server ran out before a resume: the socket is closed without waiting for its close (which a dead path can hold back for a long time), whatever it still reports is ignored, among it the 4001 the server's newest-wins sends a holder it had not reaped yet, and ondisconnect(true) has the app reconnect as after a server-side drop.

ReturnsCopy Anchor Link

void

disconnect()Copy Anchor Link

disconnect(): void;

Defined in: lib/signaling.js:511

Closes the socket; the close is reported as ondisconnect(false), not as a drop.

ReturnsCopy Anchor Link

void

sendICE()Copy Anchor Link

sendICE(ice): void;

Defined in: lib/signaling.js:520

Sends a local ICE candidate to the server peer.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

sendSDP()Copy Anchor Link

sendSDP(sdp): void;

Defined in: lib/signaling.js:529

Sends the local description (the answer) to the server peer.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

FunctionsCopy Anchor Link

newResumeKey()Copy Anchor Link

function newResumeKey(): string;

Defined in: lib/signaling.js:54

A secret naming the page's session to the server, which resumes it after a cut.

ReturnsCopy Anchor Link

string