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galene/static/protocol.js
Juliusz Chroboczek 7151fad149 Simplify the initial connection protocol.
The ServerConnection.connect method is no longer async,
we rely on the onconnected callback only.  The onconnected
callback is now only called after the initial handshake
completes.  There is a new onerror callback.
2024-06-10 21:12:47 +02:00

2205 lines
60 KiB
JavaScript

// Copyright (c) 2020 by Juliusz Chroboczek.
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
'use strict';
/**
* toHex formats an array as a hexadecimal string.
*
* @param {number[]|Uint8Array} array - the array to format
* @returns {string} - the hexadecimal representation of array
*/
function toHex(array) {
let a = new Uint8Array(array);
function hex(x) {
let h = x.toString(16);
if(h.length < 2)
h = '0' + h;
return h;
}
return a.reduce((x, y) => x + hex(y), '');
}
/**
* newRandomId returns a random string of 32 hex digits (16 bytes).
*
* @returns {string}
*/
function newRandomId() {
let a = new Uint8Array(16);
crypto.getRandomValues(a);
return toHex(a);
}
let localIdCounter = 0;
/**
* newLocalId returns a string that is unique in this session.
*
* @returns {string}
*/
function newLocalId() {
let id = `${localIdCounter}`
localIdCounter++;
return id;
}
/**
* @typedef {Object} user
* @property {string} username
* @property {Array<string>} permissions
* @property {Object<string,any>} data
* @property {Object<string,Object<string,boolean>>} streams
*/
/**
* ServerConnection encapsulates a websocket connection to the server and
* all the associated streams.
* @constructor
*/
function ServerConnection() {
/**
* The id of this connection.
*
* @type {string}
* @const
*/
this.id = newRandomId();
/**
* The group that we have joined, or null if we haven't joined yet.
*
* @type {string}
*/
this.group = null;
/**
* The username we joined as.
*
* @type {string}
*/
this.username = null;
/**
* The set of users in this group, including ourself.
*
* @type {Object<string,user>}
*/
this.users = {};
/**
* The underlying websocket.
*
* @type {WebSocket}
*/
this.socket = null;
/**
* The negotiated protocol version.
*
* @type {string}
*/
this.version = null;
/**
* The set of all up streams, indexed by their id.
*
* @type {Object<string,Stream>}
*/
this.up = {};
/**
* The set of all down streams, indexed by their id.
*
* @type {Object<string,Stream>}
*/
this.down = {};
/**
* The ICE configuration used by all associated streams.
*
* @type {RTCConfiguration}
*/
this.rtcConfiguration = null;
/**
* The permissions granted to this connection.
*
* @type {Array<string>}
*/
this.permissions = [];
/**
* userdata is a convenient place to attach data to a ServerConnection.
* It is not used by the library.
*
* @type{Object<unknown,unknown>}
*/
this.userdata = {};
/* Callbacks */
/**
* onconnected is called when the connection has been established
*
* @type{(this: ServerConnection) => void}
*/
this.onconnected = null;
/**
* onerror is called whenever a fatal error occurs. The stream will
* then be closed, and onclose called normally.
*
* @type{(this: ServerConnection, error: unknown) => void}
*/
this.onerror = null;
/**
* onclose is called when the connection is closed
*
* @type{(this: ServerConnection, code: number, reason: string) => void}
*/
this.onclose = null;
/**
* onpeerconnection is called before we establish a new peer connection.
* It may either return null, or a new RTCConfiguration that overrides
* the value obtained from the server.
*
* @type{(this: ServerConnection) => RTCConfiguration}
*/
this.onpeerconnection = null;
/**
* onuser is called whenever a user in the group changes. The users
* array has already been updated.
*
* @type{(this: ServerConnection, id: string, kind: string) => void}
*/
this.onuser = null;
/**
* onjoined is called whenever we join or leave a group or whenever the
* permissions we have in a group change.
*
* kind is one of 'join', 'fail', 'change' or 'leave'.
*
* @type{(this: ServerConnection, kind: string, group: string, permissions: Array<string>, status: Object<string,any>, data: Object<string,any>, error: string, message: string) => void}
*/
this.onjoined = null;
/**
* ondownstream is called whenever a new down stream is added. It
* should set up the stream's callbacks; actually setting up the UI
* should be done in the stream's ondowntrack callback.
*
* @type{(this: ServerConnection, stream: Stream) => void}
*/
this.ondownstream = null;
/**
* onchat is called whenever a new chat message is received.
*
* @type {(this: ServerConnection, id: string, dest: string, username: string, time: Date, privileged: boolean, history: boolean, kind: string, message: string) => void}
*/
this.onchat = null;
/**
* onusermessage is called when an application-specific message is
* received. Id is null when the message originated at the server,
* a user-id otherwise.
*
* 'kind' is typically one of 'error', 'warning', 'info' or 'mute'. If
* 'id' is non-null, 'privileged' indicates whether the message was
* sent by an operator.
*
* @type {(this: ServerConnection, id: string, dest: string, username: string, time: Date, privileged: boolean, kind: string, error: string, message: unknown) => void}
*/
this.onusermessage = null;
/**
* The set of files currently being transferred.
*
* @type {Object<string,TransferredFile>}
*/
this.transferredFiles = {};
/**
* onfiletransfer is called whenever a peer offers a file transfer.
*
* If the transfer is accepted, it should set up the file transfer
* callbacks and return immediately. It may also throw an exception
* in order to reject the file transfer.
*
* @type {(this: ServerConnection, f: TransferredFile) => void}
*/
this.onfiletransfer = null;
}
/**
* @typedef {Object} message
* @property {string} type
* @property {Array<string>} [version]
* @property {string} [kind]
* @property {string} [error]
* @property {string} [id]
* @property {string} [replace]
* @property {string} [source]
* @property {string} [dest]
* @property {string} [username]
* @property {string} [password]
* @property {string} [token]
* @property {boolean} [privileged]
* @property {Array<string>} [permissions]
* @property {Object<string,any>} [status]
* @property {Object<string,any>} [data]
* @property {string} [group]
* @property {unknown} [value]
* @property {boolean} [noecho]
* @property {string|number} [time]
* @property {string} [sdp]
* @property {RTCIceCandidate} [candidate]
* @property {string} [label]
* @property {Object<string,Array<string>>|Array<string>} [request]
* @property {Object<string,any>} [rtcConfiguration]
*/
/**
* close forcibly closes a server connection. The onclose callback will
* be called when the connection is effectively closed.
*/
ServerConnection.prototype.close = function() {
this.socket && this.socket.close(1000, 'Close requested by client');
this.socket = null;
};
/**
* error forcibly closes a server connection and invokes the onerror
* callback. The onclose callback will be invoked when the connection
* is effectively closed.
*
* @param {any} e
*/
ServerConnection.prototype.error = function(e) {
if(this.onerror)
this.onerror.call(this, e);
this.close();
};
/**
* send sends a message to the server.
* @param {message} m - the message to send.
*/
ServerConnection.prototype.send = function(m) {
if(!this.socket || this.socket.readyState !== this.socket.OPEN) {
// send on a closed socket doesn't throw
throw(new Error('Connection is not open'));
}
return this.socket.send(JSON.stringify(m));
};
/**
* connect connects to the server.
*
* @param {string} url - The URL to connect to.
* @function
*/
ServerConnection.prototype.connect = function(url) {
let sc = this;
if(sc.socket)
throw new Error("Attempting to connect stale connection");
sc.socket = new WebSocket(url);
this.socket.onerror = function(e) {
if(sc.onerror)
sc.onerror.call(sc, new Error('Socket error: ' + e));
};
this.socket.onopen = function(e) {
try {
sc.send({
type: 'handshake',
version: ['2'],
id: sc.id,
});
} catch(e) {
sc.error(e);
return;
}
};
this.socket.onclose = function(e) {
sc.permissions = [];
for(let id in sc.up) {
let c = sc.up[id];
c.close();
}
for(let id in sc.down) {
let c = sc.down[id];
c.close();
}
for(let id in sc.users) {
delete(sc.users[id]);
if(sc.onuser)
sc.onuser.call(sc, id, 'delete');
}
if(sc.group && sc.onjoined)
sc.onjoined.call(sc, 'leave', sc.group, [], {}, {}, '', '');
sc.group = null;
sc.username = null;
if(sc.onclose)
sc.onclose.call(sc, e.code, e.reason);
};
this.socket.onmessage = function(e) {
let m;
try {
m = JSON.parse(e.data);
} catch(e) {
sc.error(e);
return;
}
if(m.type !== 'handshake' && !sc.version) {
sc.error(new Error("Server didn't send handshake"));
return;
}
switch(m.type) {
case 'handshake': {
if((m.version instanceof Array) && m.version.includes('2')) {
sc.version = '2';
} else {
sc.version = null;
sc.error(new Error(`Unknown protocol version ${m.version}`));
return;
}
if(sc.onconnected)
sc.onconnected.call(sc);
break;
}
case 'offer':
sc.gotOffer(m.id, m.label, m.source, m.username,
m.sdp, m.replace);
break;
case 'answer':
sc.gotAnswer(m.id, m.sdp);
break;
case 'renegotiate':
sc.gotRenegotiate(m.id);
break;
case 'close':
sc.gotClose(m.id);
break;
case 'abort':
sc.gotAbort(m.id);
break;
case 'ice':
sc.gotRemoteIce(m.id, m.candidate);
break;
case 'joined':
if(m.kind === 'leave' || m.kind === 'fail') {
for(let id in sc.users) {
delete(sc.users[id]);
if(sc.onuser)
sc.onuser.call(sc, id, 'delete');
}
sc.username = null;
sc.permissions = [];
sc.rtcConfiguration = null;
} else if(m.kind === 'join' || m.kind == 'change') {
if(m.kind === 'join' && sc.group) {
throw new Error('Joined multiple groups');
} else if(m.kind === 'change' && m.group != sc.group) {
console.warn('join(change) for inconsistent group');
break;
}
sc.group = m.group;
sc.username = m.username;
sc.permissions = m.permissions || [];
sc.rtcConfiguration = m.rtcConfiguration || null;
}
if(sc.onjoined)
sc.onjoined.call(sc, m.kind, m.group,
m.permissions || [],
m.status, m.data,
m.error || null, m.value || null);
break;
case 'user':
switch(m.kind) {
case 'add':
if(m.id in sc.users)
console.warn(`Duplicate user ${m.id} ${m.username}`);
sc.users[m.id] = {
username: m.username,
permissions: m.permissions || [],
data: m.data || {},
streams: {},
};
break;
case 'change':
if(!(m.id in sc.users)) {
console.warn(`Unknown user ${m.id} ${m.username}`);
sc.users[m.id] = {
username: m.username,
permissions: m.permissions || [],
data: m.data || {},
streams: {},
};
} else {
sc.users[m.id].username = m.username;
sc.users[m.id].permissions = m.permissions || [];
sc.users[m.id].data = m.data || {};
}
break;
case 'delete':
if(!(m.id in sc.users))
console.warn(`Unknown user ${m.id} ${m.username}`);
for(let t in sc.transferredFiles) {
let f = sc.transferredFiles[t];
if(f.userid === m.id)
f.fail('user has gone away');
}
delete(sc.users[m.id]);
break;
default:
console.warn(`Unknown user action ${m.kind}`);
return;
}
if(sc.onuser)
sc.onuser.call(sc, m.id, m.kind);
break;
case 'chat':
case 'chathistory':
if(sc.onchat)
sc.onchat.call(
sc, m.source, m.dest, m.username, parseTime(m.time),
m.privileged, m.type === 'chathistory', m.kind,
'' + m.value,
);
break;
case 'usermessage':
if(m.kind === 'filetransfer')
sc.fileTransfer(m.source, m.username, m.value);
else if(sc.onusermessage)
sc.onusermessage.call(
sc, m.source, m.dest, m.username, parseTime(m.time),
m.privileged, m.kind, m.error, m.value,
);
break;
case 'ping':
sc.send({
type: 'pong',
});
break;
case 'pong':
/* nothing */
break;
default:
console.warn('Unexpected server message', m.type);
return;
}
};
};
/**
* Protocol version 1 uses integers for dates, later versions use dates in
* ISO 8601 format. This function takes a date in either format and
* returns a Date object.
*
* @param {string|number} value
* @returns {Date}
*/
function parseTime(value) {
if(!value)
return null;
try {
return new Date(value);
} catch(e) {
console.warn(`Couldn't parse ${value}:`, e);
return null;
}
}
/**
* join requests to join a group. The onjoined callback will be called
* when we've effectively joined.
*
* @param {string} group - The name of the group to join.
* @param {string} username - the username to join as.
* @param {string|Object} credentials - password or authServer.
* @param {Object<string,any>} [data] - the initial associated data.
*/
ServerConnection.prototype.join = async function(group, username, credentials, data) {
let m = {
type: 'join',
kind: 'join',
group: group,
};
if(typeof username !== 'undefined' && username !== null)
m.username = username;
if((typeof credentials) === 'string') {
m.password = credentials;
} else {
switch(credentials.type) {
case 'password':
m.password = credentials.password;
break;
case 'token':
m.token = credentials.token;
break;
case 'authServer':
let r = await fetch(credentials.authServer, {
method: "POST",
headers: {
"Content-Type": "application/json",
},
body: JSON.stringify({
location: credentials.location,
username: username,
password: credentials.password,
}),
});
if(!r.ok)
throw new Error(
`The authorisation server said ${r.status} ${r.statusText}`,
);
if(r.status === 204) {
// no data, fallback to password auth
m.password = credentials.password;
break;
}
let ctype = r.headers.get("Content-Type");
if(!ctype)
throw new Error(
"The authorisation server didn't return a content type",
);
let semi = ctype.indexOf(";");
if(semi >= 0)
ctype = ctype.slice(0, semi);
ctype = ctype.trim();
switch(ctype.toLowerCase()) {
case 'application/jwt':
let data = await r.text();
if(!data)
throw new Error(
"The authorisation server returned empty token",
);
m.token = data;
break;
default:
throw new Error(`The authorisation server returned ${ctype}`);
break;
}
break;
default:
throw new Error(`Unknown credentials type ${credentials.type}`);
}
}
if(data)
m.data = data;
this.send(m);
};
/**
* leave leaves a group. The onjoined callback will be called when we've
* effectively left.
*
* @param {string} group - The name of the group to join.
*/
ServerConnection.prototype.leave = function(group) {
this.send({
type: 'join',
kind: 'leave',
group: group,
});
};
/**
* request sets the list of requested tracks
*
* @param {Object<string,Array<string>>} what
* - A dictionary that maps labels to a sequence of 'audio', 'video'
* or 'video-low. An entry with an empty label '' provides the default.
*/
ServerConnection.prototype.request = function(what) {
this.send({
type: 'request',
request: what,
});
};
/**
* findByLocalId finds an active connection with the given localId.
* It returns null if none was find.
*
* @param {string} localId
* @returns {Stream}
*/
ServerConnection.prototype.findByLocalId = function(localId) {
if(!localId)
return null;
let sc = this;
for(let id in sc.up) {
let s = sc.up[id];
if(s.localId === localId)
return s;
}
return null;
}
/**
* getRTCConfiguration returns the RTCConfiguration that should be used
* with this peer connection. This usually comes from the server, but may
* be overridden by the onpeerconnection callback.
*
* @returns {RTCConfiguration}
*/
ServerConnection.prototype.getRTCConfiguration = function() {
if(this.onpeerconnection) {
let conf = this.onpeerconnection.call(this);
if(conf !== null)
return conf;
}
return this.rtcConfiguration;
}
/**
* newUpStream requests the creation of a new up stream.
*
* @param {string} [localId]
* - The local id of the stream to create. If a stream already exists with
* the same local id, it is replaced with the new stream.
* @returns {Stream}
*/
ServerConnection.prototype.newUpStream = function(localId) {
let sc = this;
let id = newRandomId();
if(sc.up[id])
throw new Error('Eek!');
if(typeof RTCPeerConnection === 'undefined')
throw new Error("This browser doesn't support WebRTC");
let pc = new RTCPeerConnection(sc.getRTCConfiguration());
if(!pc)
throw new Error("Couldn't create peer connection");
let oldId = null;
if(localId) {
let old = sc.findByLocalId(localId);
oldId = old && old.id;
if(old)
old.close(true);
}
let c = new Stream(this, id, localId || newLocalId(), pc, true);
if(oldId)
c.replace = oldId;
sc.up[id] = c;
pc.onnegotiationneeded = async e => {
await c.negotiate();
};
pc.onicecandidate = e => {
if(!e.candidate)
return;
c.gotLocalIce(e.candidate);
};
pc.oniceconnectionstatechange = e => {
if(c.onstatus)
c.onstatus.call(c, pc.iceConnectionState);
if(pc.iceConnectionState === 'failed')
c.restartIce();
};
pc.ontrack = console.error;
return c;
};
/**
* chat sends a chat message to the server. The server will normally echo
* the message back to the client.
*
* @param {string} kind
* - The kind of message, either '', 'me' or an application-specific type.
* @param {string} dest - The id to send the message to, empty for broadcast.
* @param {string} value - The text of the message.
*/
ServerConnection.prototype.chat = function(kind, dest, value) {
this.send({
type: 'chat',
source: this.id,
dest: dest,
username: this.username,
kind: kind,
value: value,
});
};
/**
* userAction sends a request to act on a user.
*
* @param {string} kind - One of "op", "unop", "kick", "present", "unpresent".
* @param {string} dest - The id of the user to act upon.
* @param {any} [value] - An action-dependent parameter.
*/
ServerConnection.prototype.userAction = function(kind, dest, value) {
this.send({
type: 'useraction',
source: this.id,
dest: dest,
username: this.username,
kind: kind,
value: value,
});
};
/**
* userMessage sends an application-specific message to a user.
* This is similar to a chat message, but is not saved in the chat history.
*
* @param {string} kind - The kind of application-specific message.
* @param {string} dest - The id to send the message to, empty for broadcast.
* @param {unknown} [value] - An optional parameter.
* @param {boolean} [noecho] - If set, don't echo back the message to the sender.
*/
ServerConnection.prototype.userMessage = function(kind, dest, value, noecho) {
this.send({
type: 'usermessage',
source: this.id,
dest: dest,
username: this.username,
kind: kind,
value: value,
noecho: noecho,
});
};
/**
* groupAction sends a request to act on the current group.
*
* @param {string} kind
* @param {any} [data]
*/
ServerConnection.prototype.groupAction = function(kind, data) {
this.send({
type: 'groupaction',
source: this.id,
kind: kind,
username: this.username,
value: data,
});
};
/**
* gotOffer is called when we receive an offer from the server. Don't call this.
*
* @param {string} id
* @param {string} label
* @param {string} source
* @param {string} username
* @param {string} sdp
* @param {string} replace
* @function
*/
ServerConnection.prototype.gotOffer = async function(id, label, source, username, sdp, replace) {
let sc = this;
if(sc.up[id]) {
console.error("Duplicate connection id");
sc.send({
type: 'abort',
id: id,
});
return;
}
let oldLocalId = null;
if(replace) {
let old = sc.down[replace];
if(old) {
oldLocalId = old.localId;
old.close(true);
} else
console.error("Replacing unknown stream");
}
let c = sc.down[id];
if(c && oldLocalId)
console.error("Replacing duplicate stream");
if(!c) {
let pc;
try {
pc = new RTCPeerConnection(sc.getRTCConfiguration());
} catch(e) {
console.error(e);
sc.send({
type: 'abort',
id: id,
});
return;
}
c = new Stream(this, id, oldLocalId || newLocalId(), pc, false);
c.label = label;
sc.down[id] = c;
c.pc.onicecandidate = function(e) {
if(!e.candidate)
return;
c.gotLocalIce(e.candidate);
};
pc.oniceconnectionstatechange = e => {
if(c.onstatus)
c.onstatus.call(c, pc.iceConnectionState);
if(pc.iceConnectionState === 'failed') {
sc.send({
type: 'renegotiate',
id: id,
});
}
};
c.pc.ontrack = function(e) {
if(e.streams.length < 1) {
console.error("Got track with no stream");
return;
}
c.stream = e.streams[0];
let changed = recomputeUserStreams(sc, source);
if(c.ondowntrack) {
c.ondowntrack.call(
c, e.track, e.transceiver, e.streams[0],
);
}
if(changed && sc.onuser)
sc.onuser.call(sc, source, "change");
};
}
c.source = source;
c.username = username;
if(sc.ondownstream)
sc.ondownstream.call(sc, c);
try {
await c.pc.setRemoteDescription({
type: 'offer',
sdp: sdp,
});
await c.flushRemoteIceCandidates();
let answer = await c.pc.createAnswer();
if(!answer)
throw new Error("Didn't create answer");
await c.pc.setLocalDescription(answer);
this.send({
type: 'answer',
id: id,
sdp: c.pc.localDescription.sdp,
});
} catch(e) {
try {
if(c.onerror)
c.onerror.call(c, e);
} finally {
c.abort();
}
return;
}
c.localDescriptionSent = true;
c.flushLocalIceCandidates();
if(c.onnegotiationcompleted)
c.onnegotiationcompleted.call(c);
};
/**
* gotAnswer is called when we receive an answer from the server. Don't
* call this.
*
* @param {string} id
* @param {string} sdp
* @function
*/
ServerConnection.prototype.gotAnswer = async function(id, sdp) {
let c = this.up[id];
if(!c)
throw new Error('unknown up stream');
try {
await c.pc.setRemoteDescription({
type: 'answer',
sdp: sdp,
});
} catch(e) {
try {
if(c.onerror)
c.onerror.call(c, e);
} finally {
c.close();
}
return;
}
await c.flushRemoteIceCandidates();
if(c.onnegotiationcompleted)
c.onnegotiationcompleted.call(c);
};
/**
* gotRenegotiate is called when we receive a renegotiation request from
* the server. Don't call this.
*
* @param {string} id
* @function
*/
ServerConnection.prototype.gotRenegotiate = function(id) {
let c = this.up[id];
if(!c)
throw new Error('unknown up stream');
c.restartIce();
};
/**
* gotClose is called when we receive a close request from the server.
* Don't call this.
*
* @param {string} id
*/
ServerConnection.prototype.gotClose = function(id) {
let c = this.down[id];
if(!c) {
console.warn('unknown down stream', id);
return;
}
c.close();
};
/**
* gotAbort is called when we receive an abort message from the server.
* Don't call this.
*
* @param {string} id
*/
ServerConnection.prototype.gotAbort = function(id) {
let c = this.up[id];
if(!c)
throw new Error('unknown up stream');
c.close();
};
/**
* gotRemoteIce is called when we receive an ICE candidate from the server.
* Don't call this.
*
* @param {string} id
* @param {RTCIceCandidate} candidate
* @function
*/
ServerConnection.prototype.gotRemoteIce = async function(id, candidate) {
let c = this.up[id];
if(!c)
c = this.down[id];
if(!c)
throw new Error('unknown stream');
if(c.pc.remoteDescription)
await c.pc.addIceCandidate(candidate).catch(console.warn);
else
c.remoteIceCandidates.push(candidate);
};
/**
* Stream encapsulates a MediaStream, a set of tracks.
*
* A stream is said to go "up" if it is from the client to the server, and
* "down" otherwise.
*
* @param {ServerConnection} sc
* @param {string} id
* @param {string} localId
* @param {RTCPeerConnection} pc
*
* @constructor
*/
function Stream(sc, id, localId, pc, up) {
/**
* The associated ServerConnection.
*
* @type {ServerConnection}
* @const
*/
this.sc = sc;
/**
* The id of this stream.
*
* @type {string}
* @const
*/
this.id = id;
/**
* The local id of this stream.
*
* @type {string}
* @const
*/
this.localId = localId;
/**
* Indicates whether the stream is in the client->server direction.
*
* @type {boolean}
* @const
*/
this.up = up;
/**
* For down streams, the id of the client that created the stream.
*
* @type {string}
*/
this.source = null;
/**
* For down streams, the username of the client who created the stream.
*
* @type {string}
*/
this.username = null;
/**
* The associated RTCPeerConnection. This is null before the stream
* is connected, and may change over time.
*
* @type {RTCPeerConnection}
*/
this.pc = pc;
/**
* The associated MediaStream. This is null before the stream is
* connected, and may change over time.
*
* @type {MediaStream}
*/
this.stream = null;
/**
* The label assigned by the originator to this stream.
*
* @type {string}
*/
this.label = null;
/**
* The id of the stream that we are currently replacing.
*
* @type {string}
*/
this.replace = null;
/**
* Indicates whether we have already sent a local description.
*
* @type {boolean}
*/
this.localDescriptionSent = false;
/**
* Buffered local ICE candidates. This will be flushed by
* flushLocalIceCandidates after we send a local description.
*
* @type {RTCIceCandidate[]}
*/
this.localIceCandidates = [];
/**
* Buffered remote ICE candidates. This will be flushed by
* flushRemoteIceCandidates when we get a remote SDP description.
*
* @type {RTCIceCandidate[]}
*/
this.remoteIceCandidates = [];
/**
* The statistics last computed by the stats handler. This is
* a dictionary indexed by track id, with each value a dictionary of
* statistics.
*
* @type {Object<string,unknown>}
*/
this.stats = {};
/**
* The id of the periodic handler that computes statistics, as
* returned by setInterval.
*
* @type {number}
*/
this.statsHandler = null;
/**
* userdata is a convenient place to attach data to a Stream.
* It is not used by the library.
*
* @type{Object<unknown,unknown>}
*/
this.userdata = {};
/* Callbacks */
/**
* onclose is called when the stream is closed. Replace will be true
* if the stream is being replaced by another one with the same id.
*
* @type{(this: Stream, replace: boolean) => void}
*/
this.onclose = null;
/**
* onerror is called whenever a fatal error occurs. The stream will
* then be closed, and onclose called normally.
*
* @type{(this: Stream, error: unknown) => void}
*/
this.onerror = null;
/**
* onnegotiationcompleted is called whenever negotiation or
* renegotiation has completed.
*
* @type{(this: Stream) => void}
*/
this.onnegotiationcompleted = null;
/**
* ondowntrack is called whenever a new track is added to a stream.
* If the stream parameter differs from its previous value, then it
* indicates that the old stream has been discarded.
*
* @type{(this: Stream, track: MediaStreamTrack, transceiver: RTCRtpTransceiver, stream: MediaStream) => void}
*/
this.ondowntrack = null;
/**
* onstatus is called whenever the status of the stream changes.
*
* @type{(this: Stream, status: string) => void}
*/
this.onstatus = null;
/**
* onstats is called when we have new statistics about the connection
*
* @type{(this: Stream, stats: Object<unknown,unknown>) => void}
*/
this.onstats = null;
}
/**
* setStream sets the stream of an upwards connection.
*
* @param {MediaStream} stream
*/
Stream.prototype.setStream = function(stream) {
let c = this;
c.stream = stream;
let changed = recomputeUserStreams(c.sc, c.sc.id);
if(changed && c.sc.onuser)
c.sc.onuser.call(c.sc, c.sc.id, "change");
}
/**
* close closes a stream.
*
* For streams in the up direction, this may be called at any time. For
* streams in the down direction, this will be called automatically when
* the server signals that it is closing a stream.
*
* @param {boolean} [replace]
* - true if the stream is being replaced by another one with the same id
*/
Stream.prototype.close = function(replace) {
let c = this;
if(!c.sc) {
console.warn('Closing closed stream');
return;
}
if(c.statsHandler) {
clearInterval(c.statsHandler);
c.statsHandler = null;
}
c.pc.close();
if(c.up && !replace && c.localDescriptionSent) {
try {
c.sc.send({
type: 'close',
id: c.id,
});
} catch(e) {
}
}
let userid;
if(c.up) {
userid = c.sc.id;
if(c.sc.up[c.id] === c)
delete(c.sc.up[c.id]);
else
console.warn('Closing unknown stream');
} else {
userid = c.source;
if(c.sc.down[c.id] === c)
delete(c.sc.down[c.id]);
else
console.warn('Closing unknown stream');
}
let changed = recomputeUserStreams(c.sc, userid);
if(changed && c.sc.onuser)
c.sc.onuser.call(c.sc, userid, "change");
if(c.onclose)
c.onclose.call(c, replace);
c.sc = null;
};
/**
* recomputeUserStreams recomputes the user.streams array for a given user.
* It returns true if anything changed.
*
* @param {ServerConnection} sc
* @param {string} id
* @returns {boolean}
*/
function recomputeUserStreams(sc, id) {
let user = sc.users[id];
if(!user) {
console.warn("recomputing streams for unknown user");
return false;
}
let streams = id === sc.id ? sc.up : sc.down;
let old = user.streams;
user.streams = {};
for(id in streams) {
let c = streams[id];
if(!c.stream)
continue;
if(!user.streams[c.label])
user.streams[c.label] = {};
c.stream.getTracks().forEach(t => {
user.streams[c.label][t.kind] = true;
});
}
return JSON.stringify(old) != JSON.stringify(user.streams);
}
/**
* abort requests that the server close a down stream.
*/
Stream.prototype.abort = function() {
let c = this;
if(c.up)
throw new Error("Abort called on an up stream");
c.sc.send({
type: 'abort',
id: c.id,
});
};
/**
* gotLocalIce is Called when we get a local ICE candidate. Don't call this.
*
* @param {RTCIceCandidate} candidate
* @function
*/
Stream.prototype.gotLocalIce = function(candidate) {
let c = this;
if(c.localDescriptionSent)
c.sc.send({type: 'ice',
id: c.id,
candidate: candidate,
});
else
c.localIceCandidates.push(candidate);
};
/**
* flushLocalIceCandidates flushes any buffered local ICE candidates.
* It is called when we send an offer.
*
* @function
*/
Stream.prototype.flushLocalIceCandidates = function () {
let c = this;
let candidates = c.localIceCandidates;
c.localIceCandidates = [];
candidates.forEach(candidate => {
try {
c.sc.send({type: 'ice',
id: c.id,
candidate: candidate,
});
} catch(e) {
console.warn(e);
}
});
c.localIceCandidates = [];
};
/**
* flushRemoteIceCandidates flushes any buffered remote ICE candidates. It is
* called automatically when we get a remote description.
*
* @function
*/
Stream.prototype.flushRemoteIceCandidates = async function () {
let c = this;
let candidates = c.remoteIceCandidates;
c.remoteIceCandidates = [];
/** @type {Array.<Promise<void>>} */
let promises = [];
candidates.forEach(candidate => {
promises.push(c.pc.addIceCandidate(candidate).catch(console.warn));
});
return await Promise.all(promises);
};
/**
* negotiate negotiates or renegotiates an up stream. It is called
* automatically when required. If the client requires renegotiation, it
* is probably better to call restartIce which will cause negotiate to be
* called asynchronously.
*
* @function
* @param {boolean} [restartIce] - Whether to restart ICE.
*/
Stream.prototype.negotiate = async function (restartIce) {
let c = this;
if(!c.up)
throw new Error('not an up stream');
let options = {};
if(restartIce)
options = {iceRestart: true};
let offer = await c.pc.createOffer(options);
if(!offer)
throw(new Error("Didn't create offer"));
await c.pc.setLocalDescription(offer);
c.sc.send({
type: 'offer',
source: c.sc.id,
username: c.sc.username,
kind: this.localDescriptionSent ? 'renegotiate' : '',
id: c.id,
replace: this.replace,
label: c.label,
sdp: c.pc.localDescription.sdp,
});
this.localDescriptionSent = true;
this.replace = null;
c.flushLocalIceCandidates();
};
/**
* restartIce causes an ICE restart on a stream. For up streams, it is
* called automatically when ICE signals that the connection has failed,
* but may also be called by the application. For down streams, it
* requests that the server perform an ICE restart. In either case,
* it returns immediately, negotiation will happen asynchronously.
*/
Stream.prototype.restartIce = function () {
let c = this;
if(!c.up) {
c.sc.send({
type: 'renegotiate',
id: c.id,
});
return;
}
if('restartIce' in c.pc) {
try {
c.pc.restartIce();
return;
} catch(e) {
console.warn(e);
}
}
// negotiate is async, but this returns immediately.
c.negotiate(true);
};
/**
* request sets the list of tracks. If this is not called, or called with
* a null argument, then the default is provided by ServerConnection.request.
*
* @param {Array<string>} what - a sequence of 'audio', 'video' or 'video-low'.
*/
Stream.prototype.request = function(what) {
let c = this;
c.sc.send({
type: 'requestStream',
id: c.id,
request: what,
});
};
/**
* updateStats is called periodically, if requested by setStatsInterval,
* in order to recompute stream statistics and invoke the onstats handler.
*
* @function
*/
Stream.prototype.updateStats = async function() {
let c = this;
let old = c.stats;
/** @type{Object<string,unknown>} */
let stats = {};
let transceivers = c.pc.getTransceivers();
for(let i = 0; i < transceivers.length; i++) {
let t = transceivers[i];
let stid = t.sender.track && t.sender.track.id;
let rtid = t.receiver.track && t.receiver.track.id;
let report = null;
if(stid) {
try {
report = await t.sender.getStats();
} catch(e) {
}
}
if(report) {
for(let r of report.values()) {
if(stid && r.type === 'outbound-rtp') {
let id = stid;
// Firefox doesn't implement rid, use ssrc
// to discriminate simulcast tracks.
id = id + '-' + r.ssrc;
if(!('bytesSent' in r))
continue;
if(!stats[id])
stats[id] = {};
stats[id][r.type] = {};
stats[id][r.type].timestamp = r.timestamp;
stats[id][r.type].bytesSent = r.bytesSent;
if(old[id] && old[id][r.type])
stats[id][r.type].rate =
((r.bytesSent - old[id][r.type].bytesSent) * 1000 /
(r.timestamp - old[id][r.type].timestamp)) * 8;
}
}
}
report = null;
if(rtid) {
try {
report = await t.receiver.getStats();
} catch(e) {
console.error(e);
}
}
if(report) {
for(let r of report.values()) {
if(rtid && r.type === 'inbound-rtp') {
if(!('totalAudioEnergy' in r))
continue;
if(!stats[rtid])
stats[rtid] = {};
stats[rtid][r.type] = {};
stats[rtid][r.type].timestamp = r.timestamp;
stats[rtid][r.type].totalAudioEnergy = r.totalAudioEnergy;
if(old[rtid] && old[rtid][r.type])
stats[rtid][r.type].audioEnergy =
(r.totalAudioEnergy - old[rtid][r.type].totalAudioEnergy) * 1000 /
(r.timestamp - old[rtid][r.type].timestamp);
}
}
}
}
c.stats = stats;
if(c.onstats)
c.onstats.call(c, c.stats);
};
/**
* setStatsInterval sets the interval in milliseconds at which the onstats
* handler will be called. This is only useful for up streams.
*
* @param {number} ms - The interval in milliseconds.
*/
Stream.prototype.setStatsInterval = function(ms) {
let c = this;
if(c.statsHandler) {
clearInterval(c.statsHandler);
c.statsHandler = null;
}
if(ms <= 0)
return;
c.statsHandler = setInterval(() => {
c.updateStats();
}, ms);
};
/**
* A file in the process of being transferred.
* These are stored in the ServerConnection.transferredFiles dictionary.
*
* State transitions:
* @example
* '' -> inviting -> connecting -> connected -> done -> closed
* any -> cancelled -> closed
*
*
* @parm {ServerConnection} sc
* @parm {string} userid
* @parm {string} rid
* @parm {boolean} up
* @parm {string} username
* @parm {string} mimetype
* @parm {number} size
* @constructor
*/
function TransferredFile(sc, userid, id, up, username, name, mimetype, size) {
/**
* The server connection this file is associated with.
*
* @type {ServerConnection}
*/
this.sc = sc;
/** The id of the remote peer.
*
* @type {string}
*/
this.userid = userid;
/**
* The id of this file transfer.
*
* @type {string}
*/
this.id = id;
/**
* True if this is an upload.
*
* @type {boolean}
*/
this.up = up;
/**
* The state of this file transfer. See the description of the
* constructor for possible state transitions.
*
* @type {string}
*/
this.state = '';
/**
* The username of the remote peer.
*
* @type {string}
*/
this.username = username;
/**
* The name of the file being transferred.
*
* @type {string}
*/
this.name = name;
/**
* The MIME type of the file being transferred.
*
* @type {string}
*/
this.mimetype = mimetype;
/**
* The size in bytes of the file being transferred.
*
* @type {number}
*/
this.size = size;
/**
* The file being uploaded. Unused for downloads.
*
* @type {File}
*/
this.file = null;
/**
* The peer connection used for the transfer.
*
* @type {RTCPeerConnection}
*/
this.pc = null;
/**
* The datachannel used for the transfer.
*
* @type {RTCDataChannel}
*/
this.dc = null;
/**
* Buffered remote ICE candidates.
*
* @type {Array<RTCIceCandidateInit>}
*/
this.candidates = [];
/**
* The data received to date, stored as a list of blobs or array buffers,
* depending on what the browser supports.
*
* @type {Array<Blob|ArrayBuffer>}
*/
this.data = [];
/**
* The total size of the data received to date.
*
* @type {number}
*/
this.datalen = 0;
/**
* The main filetransfer callback.
*
* This is called whenever the state of the transfer changes,
* but may also be called multiple times in a single state, for example
* in order to display a progress bar. Call this.cancel in order
* to cancel the transfer.
*
* @type {(this: TransferredFile, type: string, [data]: string) => void}
*/
this.onevent = null;
}
/**
* The full id of this file transfer, used as a key in the transferredFiles
* dictionary.
*/
TransferredFile.prototype.fullid = function() {
return this.userid + (this.up ? '+' : '-') + this.id;
};
/**
* Retrieve a transferred file from the transferredFiles dictionary.
*
* @param {string} userid
* @param {string} fileid
* @param {boolean} up
* @returns {TransferredFile}
*/
ServerConnection.prototype.getTransferredFile = function(userid, fileid, up) {
return this.transferredFiles[userid + (up ? '+' : '-') + fileid];
};
/**
* Close a file transfer and remove it from the transferredFiles dictionary.
* Do not call this, call 'cancel' instead.
*/
TransferredFile.prototype.close = function() {
let f = this;
if(f.state === 'closed')
return;
if(f.state !== 'done' && f.state !== 'cancelled')
console.warn(
`TransferredFile.close called in unexpected state ${f.state}`,
);
if(f.dc) {
f.dc.onclose = null;
f.dc.onerror = null;
f.dc.onmessage = null;
}
if(f.pc)
f.pc.close();
f.dc = null;
f.pc = null;
f.data = [];
f.datalen = 0;
delete(f.sc.transferredFiles[f.fullid()]);
f.event('closed');
}
/**
* Buffer a chunk of data received during a file transfer.
* Do not call this, it is called automatically when data is received.
*
* @param {Blob|ArrayBuffer} data
*/
TransferredFile.prototype.bufferData = function(data) {
let f = this;
if(f.up)
throw new Error('buffering data in the wrong direction');
if(data instanceof Blob) {
f.datalen += data.size;
} else if(data instanceof ArrayBuffer) {
f.datalen += data.byteLength;
} else {
throw new Error('unexpected type for received data');
}
f.data.push(data);
}
/**
* Retreive the data buffered during a file transfer. Don't call this.
*
* @returns {Blob}
*/
TransferredFile.prototype.getBufferedData = function() {
let f = this;
if(f.up)
throw new Error('buffering data in wrong direction');
let blob = new Blob(f.data, {type: f.mimetype});
if(blob.size != f.datalen)
throw new Error('Inconsistent data size');
f.data = [];
f.datalen = 0;
return blob;
}
/**
* Set the file's state, and call the onevent callback.
*
* This calls the callback even if the state didn't change, which is
* useful if the client needs to display a progress bar.
*
* @param {string} state
* @param {any} [data]
*/
TransferredFile.prototype.event = function(state, data) {
let f = this;
f.state = state;
if(f.onevent)
f.onevent.call(f, state, data);
}
/**
* Cancel a file transfer.
*
* Depending on the state, this will either forcibly close the connection,
* send a handshake, or do nothing. It will set the state to cancelled.
*
* @param {string|Error} [data]
*/
TransferredFile.prototype.cancel = function(data) {
let f = this;
if(f.state === 'closed')
return;
if(f.state !== '' && f.state !== 'done' && f.state !== 'cancelled') {
let m = {
type: f.up ? 'cancel' : 'reject',
id: f.id,
};
if(data)
m.message = data.toString();
f.sc.userMessage('filetransfer', f.userid, m);
}
if(f.state !== 'done' && f.state !== 'cancelled')
f.event('cancelled', data);
f.close();
}
/**
* Forcibly terminate a file transfer.
*
* This is like cancel, but will not attempt to handshake.
* Use cancel instead of this, unless you know what you are doing.
*
* @param {string|Error} [data]
*/
TransferredFile.prototype.fail = function(data) {
let f = this;
if(f.state === 'done' || f.state === 'cancelled' || f.state === 'closed')
return;
f.event('cancelled', data);
f.close();
}
/**
* Initiate a file upload.
*
* This will cause the onfiletransfer callback to be called, at which
* point you should set up the onevent callback.
*
* @param {string} id
* @param {File} file
*/
ServerConnection.prototype.sendFile = function(id, file) {
let sc = this;
let fileid = newRandomId();
let user = sc.users[id];
if(!user)
throw new Error('offering upload to unknown user');
let f = new TransferredFile(
sc, id, fileid, true, user.username, file.name, file.type, file.size,
);
f.file = file;
try {
if(sc.onfiletransfer)
sc.onfiletransfer.call(sc, f);
else
throw new Error('this client does not implement file transfer');
} catch(e) {
f.cancel(e);
return;
}
sc.transferredFiles[f.fullid()] = f;
sc.userMessage('filetransfer', id, {
type: 'invite',
id: fileid,
name: f.name,
size: f.size,
mimetype: f.mimetype,
});
f.event('inviting');
}
/**
* Receive a file.
*
* Call this after the onfiletransfer callback has yielded an incoming
* file (up field set to false). If you wish to reject the file transfer,
* call cancel instead.
*/
TransferredFile.prototype.receive = async function() {
let f = this;
if(f.up)
throw new Error('Receiving in wrong direction');
if(f.pc)
throw new Error('Download already in progress');
let pc = new RTCPeerConnection(f.sc.getRTCConfiguration());
if(!pc) {
let err = new Error("Couldn't create peer connection");
f.fail(err);
return;
}
f.pc = pc;
f.event('connecting');
f.candidates = [];
pc.onsignalingstatechange = function(e) {
if(pc.signalingState === 'stable') {
f.candidates.forEach(c => pc.addIceCandidate(c).catch(console.warn));
f.candidates = [];
}
};
pc.onicecandidate = function(e) {
f.sc.userMessage('filetransfer', f.userid, {
type: 'downice',
id: f.id,
candidate: e.candidate,
});
};
f.dc = pc.createDataChannel('file');
f.data = [];
f.datalen = 0;
f.dc.onclose = function(e) {
f.cancel('remote peer closed connection');
};
f.dc.onmessage = function(e) {
f.receiveData(e.data).catch(e => f.cancel(e));
};
f.dc.onerror = function(e) {
/** @ts-ignore */
let err = e.error;
f.cancel(err)
};
let offer = await pc.createOffer();
if(!offer) {
f.cancel(new Error("Couldn't create offer"));
return;
}
await pc.setLocalDescription(offer);
f.sc.userMessage('filetransfer', f.userid, {
type: 'offer',
id: f.id,
sdp: pc.localDescription.sdp,
});
}
/**
* Negotiate a file transfer on the sender side.
* Don't call this, it is called automatically we receive an offer.
*
* @param {string} sdp
*/
TransferredFile.prototype.answer = async function(sdp) {
let f = this;
if(!f.up)
throw new Error('Sending file in wrong direction');
if(f.pc)
throw new Error('Transfer already in progress');
let pc = new RTCPeerConnection(f.sc.getRTCConfiguration());
if(!pc) {
let err = new Error("Couldn't create peer connection");
f.fail(err);
return;
}
f.pc = pc;
f.event('connecting');
f.candidates = [];
pc.onicecandidate = function(e) {
f.sc.userMessage('filetransfer', f.userid, {
type: 'upice',
id: f.id,
candidate: e.candidate,
});
};
pc.onsignalingstatechange = function(e) {
if(pc.signalingState === 'stable') {
f.candidates.forEach(c => pc.addIceCandidate(c).catch(console.warn));
f.candidates = [];
}
};
pc.ondatachannel = function(e) {
if(f.dc) {
f.cancel(new Error('Duplicate datachannel'));
return;
}
f.dc = /** @type{RTCDataChannel} */(e.channel);
f.dc.onclose = function(e) {
f.cancel('remote peer closed connection');
};
f.dc.onerror = function(e) {
/** @ts-ignore */
let err = e.error;
f.cancel(err);
}
f.dc.onmessage = function(e) {
if(e.data === 'done' && f.datalen === f.size) {
f.event('done');
f.dc.onclose = null;
f.dc.onerror = null;
f.close();
} else {
f.cancel(new Error('unexpected data from receiver'));
}
}
f.send().catch(e => f.cancel(e));
};
await pc.setRemoteDescription({
type: 'offer',
sdp: sdp,
});
let answer = await pc.createAnswer();
if(!answer)
throw new Error("Couldn't create answer");
await pc.setLocalDescription(answer);
f.sc.userMessage('filetransfer', f.userid, {
type: 'answer',
id: f.id,
sdp: pc.localDescription.sdp,
});
f.event('connected');
}
/**
* Transfer file data. Don't call this, it is called automatically
* after negotiation completes.
*/
TransferredFile.prototype.send = async function() {
let f = this;
if(!f.up)
throw new Error('sending in wrong direction');
let r = f.file.stream().getReader();
f.dc.bufferedAmountLowThreshold = 65536;
/** @param {Uint8Array} a */
async function write(a) {
while(f.dc.bufferedAmount > f.dc.bufferedAmountLowThreshold) {
await new Promise((resolve, reject) => {
if(!f.dc) {
reject(new Error('File is closed.'));
return;
}
f.dc.onbufferedamountlow = function(e) {
if(!f.dc) {
reject(new Error('File is closed.'));
return;
}
f.dc.onbufferedamountlow = null;
resolve();
}
});
}
f.dc.send(a);
f.datalen += a.length;
// we're already in the connected state, but invoke callbacks to
// that the application can display progress
f.event('connected');
}
while(true) {
let v = await r.read();
if(v.done)
break;
let data = v.value;
if(!(data instanceof Uint8Array))
throw new Error('Unexpected type for chunk');
/* Base SCTP only supports up to 16kB data chunks. There are
extensions to handle larger chunks, but they don't interoperate
between browsers, so we chop the file into small pieces. */
if(data.length <= 16384) {
await write(data);
} else {
for(let i = 0; i < v.value.length; i += 16384) {
let d = data.subarray(i, Math.min(i + 16384, data.length));
await write(d);
}
}
}
}
/**
* Called after we receive an answer. Don't call this.
*
* @param {string} sdp
*/
TransferredFile.prototype.receiveFile = async function(sdp) {
let f = this;
if(f.up)
throw new Error('Receiving in wrong direction');
await f.pc.setRemoteDescription({
type: 'answer',
sdp: sdp,
});
f.event('connected');
}
/**
* Called whenever we receive a chunk of data. Don't call this.
*
* @param {Blob|ArrayBuffer} data
*/
TransferredFile.prototype.receiveData = async function(data) {
let f = this;
if(f.up)
throw new Error('Receiving in wrong direction');
f.bufferData(data);
if(f.datalen < f.size) {
f.event('connected');
return;
}
f.dc.onmessage = null;
if(f.datalen != f.size) {
f.cancel('extra data at end of file');
return;
}
let blob = f.getBufferedData();
if(blob.size != f.size) {
f.cancel("inconsistent data size (this shouldn't happen)");
return;
}
f.event('done', blob);
// we've received the whole file. Send the final handshake, but don't
// complain if the peer has closed the channel in the meantime.
await new Promise((resolve, reject) => {
let timer = setTimeout(function(e) { resolve(); }, 2000);
f.dc.onclose = function(e) {
clearTimeout(timer);
resolve();
};
f.dc.onerror = function(e) {
clearTimeout(timer);
resolve();
};
f.dc.send('done');
});
f.close();
}
/**
* fileTransfer handles a usermessage of kind 'filetransfer'. Don't call
* this, it is called automatically as needed.
*
* @param {string} id
* @param {string} username
* @param {object} message
*/
ServerConnection.prototype.fileTransfer = function(id, username, message) {
let sc = this;
switch(message.type) {
case 'invite': {
let f = new TransferredFile(
sc, id, message.id, false, username,
message.name, message.mimetype, message.size,
);
f.state = 'inviting';
try {
if(sc.onfiletransfer)
sc.onfiletransfer.call(sc, f);
else {
f.cancel('this client does not implement file transfer');
return;
}
} catch(e) {
f.cancel(e);
return;
}
if(f.fullid() in sc.transferredFiles) {
console.error('Duplicate id for file transfer');
f.cancel("duplicate id (this shouldn't happen)");
return;
}
sc.transferredFiles[f.fullid()] = f;
break;
}
case 'offer': {
let f = sc.getTransferredFile(id, message.id, true);
if(!f) {
console.error('Unexpected offer for file transfer');
return;
}
f.answer(message.sdp).catch(e => f.cancel(e));
break;
}
case 'answer': {
let f = sc.getTransferredFile(id, message.id, false);
if(!f) {
console.error('Unexpected answer for file transfer');
return;
}
f.receiveFile(message.sdp).catch(e => f.cancel(e));
break;
}
case 'downice':
case 'upice': {
let f = sc.getTransferredFile(
id, message.id, message.type === 'downice',
);
if(!f || !f.pc) {
console.warn(`Unexpected ${message.type} for file transfer`);
return;
}
if(f.pc.signalingState === 'stable')
f.pc.addIceCandidate(message.candidate).catch(console.warn);
else
f.candidates.push(message.candidate);
break;
}
case 'cancel':
case 'reject': {
let f = sc.getTransferredFile(id, message.id, message.type === 'reject');
if(!f) {
console.error(`Unexpected ${message.type} for file transfer`);
return;
}
f.event('cancelled', message.value || null);
f.close();
break;
}
default:
console.error(`Unknown filetransfer message ${message.type}`);
break;
}
}