148 lines
4 KiB
JavaScript
148 lines
4 KiB
JavaScript
(function () {
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var TYPE_FRAME = 0;
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var TYPE_ACK = 1;
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function WSShim(url) {
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this._url = url;
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this._listeners = Object.create(null);
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this._connected = false;
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this._ackId = 0;
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this._pendingAcks = Object.create(null);
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this._openWS();
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}
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WSShim.prototype.listeners = function listeners(frame) {
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if (!Object.prototype.hasOwnProperty.call(this._listeners, frame)) {
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this._listeners[frame] = [];
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}
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return this._listeners[frame];
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};
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WSShim.prototype.on = function on(frame, callback) {
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this.listeners(frame).push(callback);
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};
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WSShim.prototype.once = function on(frame, callback) {
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callback._once = true;
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this.listeners(frame).push(callback);
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};
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WSShim.prototype.emit = function emit(frame, payload, ack) {
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var message = {
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type: TYPE_FRAME,
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frame: frame,
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payload: payload
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};
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if (ack && typeof ack === 'function') {
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message.ackId = ++this._ackId;
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this._pendingAcks[message.ackId] = ack;
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}
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this._ws.send(JSON.stringify(message));
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};
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WSShim.prototype._emit = function _emit(frame, payload) {
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var hasOnce = false;
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this.listeners(frame).forEach(function (cb) {
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try {
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if (cb._once) {
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hasOnce = true;
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}
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cb(payload);
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} catch (error) {
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console.error('Error in callback for ' + frame + ': ' + error);
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}
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});
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if (hasOnce) {
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this._listeners[frame] = this._listeners[frame].filter(function (cb) {
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return !cb._once;
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});
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}
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};
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WSShim.prototype._onopen = function _onopen() {
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this._connected = true;
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};
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WSShim.prototype._onclose = function _onclose() {
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if (!this._connected) {
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return;
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}
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this._connected = false;
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this._emit('disconnect');
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// TODO: checking for KICKED here is insufficient;
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// need to have some sort of explicit disconnect vs. connection loss
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// check
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if (!KICKED) {
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var self = this;
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function reconnectAsync(cb) {
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self._openWS();
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self._ws.addEventListener('open', function () {
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cb(null);
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});
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self._ws.addEventListener('error', function (error) {
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cb(error);
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});
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}
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var retryOpts = {
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delay: 1000,
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jitter: 1000,
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factor: 2,
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maxDelay: 20000
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};
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setTimeout(function () {
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backoffRetry(reconnectAsync, function(){}, retryOpts);
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}, 1000);
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}
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};
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WSShim.prototype._onmessage = function _onmessage(message) {
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try {
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var parsed = JSON.parse(message.data);
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var type = parsed.type;
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var frame = parsed.frame;
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var payload = parsed.payload;
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var ackId = parsed.ackId;
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if (type === TYPE_ACK && ackId in this._pendingAcks) {
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this._pendingAcks[ackId](payload);
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delete this._pendingAcks[ackId];
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} else if (type === TYPE_FRAME) {
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this._emit(frame, payload);
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}
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} catch (error) {
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console.error('Unparseable message from server: ' + message);
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console.error(error.stack);
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return;
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}
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};
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WSShim.prototype._openWS = function _openWS() {
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if (this._connected) {
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throw new Error('Cannot _openWS() when already connected');
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}
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this._ws = new WebSocket(this._url);
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this._ws.onopen = this._onopen.bind(this);
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this._ws.onclose = this._onclose.bind(this);
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this._ws.onmessage = this._onmessage.bind(this);
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this._connected = false;
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};
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window.WSShim = WSShim;
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})();
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