invidious/assets/js/sse.js

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2019-05-05 18:16:01 +05:30
/**
* Copyright (C) 2016 Maxime Petazzoni <maxime.petazzoni@bulix.org>.
* All rights reserved.
*/
var SSE = function (url, options) {
if (!(this instanceof SSE)) {
return new SSE(url, options);
}
this.INITIALIZING = -1;
this.CONNECTING = 0;
this.OPEN = 1;
this.CLOSED = 2;
this.url = url;
options = options || {};
this.headers = options.headers || {};
this.payload = options.payload !== undefined ? options.payload : '';
this.method = options.method || (this.payload && 'POST' || 'GET');
this.FIELD_SEPARATOR = ':';
this.listeners = {};
this.xhr = null;
this.readyState = this.INITIALIZING;
this.progress = 0;
this.chunk = '';
this.addEventListener = function(type, listener) {
if (this.listeners[type] === undefined) {
this.listeners[type] = [];
}
if (this.listeners[type].indexOf(listener) === -1) {
this.listeners[type].push(listener);
}
};
this.removeEventListener = function(type, listener) {
if (this.listeners[type] === undefined) {
return;
}
var filtered = [];
this.listeners[type].forEach(function(element) {
if (element !== listener) {
filtered.push(element);
}
});
if (filtered.length === 0) {
delete this.listeners[type];
} else {
this.listeners[type] = filtered;
}
};
this.dispatchEvent = function(e) {
if (!e) {
return true;
}
e.source = this;
var onHandler = 'on' + e.type;
if (this.hasOwnProperty(onHandler)) {
this[onHandler].call(this, e);
if (e.defaultPrevented) {
return false;
}
}
if (this.listeners[e.type]) {
return this.listeners[e.type].every(function(callback) {
callback(e);
return !e.defaultPrevented;
});
}
return true;
};
this._setReadyState = function (state) {
var event = new CustomEvent('readystatechange');
event.readyState = state;
this.readyState = state;
this.dispatchEvent(event);
};
this._onStreamFailure = function(e) {
this.dispatchEvent(new CustomEvent('error'));
this.close();
}
this._onStreamProgress = function(e) {
if (this.xhr.status !== 200 && this.readyState !== this.CLOSED) {
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this._onStreamFailure(e);
return;
}
if (this.readyState == this.CONNECTING) {
this.dispatchEvent(new CustomEvent('open'));
this._setReadyState(this.OPEN);
}
var data = this.xhr.responseText.substring(this.progress);
this.progress += data.length;
data.split(/(\r\n|\r|\n){2}/g).forEach(function(part) {
if (part.trim().length === 0) {
this.dispatchEvent(this._parseEventChunk(this.chunk.trim()));
this.chunk = '';
} else {
this.chunk += part;
}
}.bind(this));
};
this._onStreamLoaded = function(e) {
this._onStreamProgress(e);
// Parse the last chunk.
this.dispatchEvent(this._parseEventChunk(this.chunk));
this.chunk = '';
};
/**
* Parse a received SSE event chunk into a constructed event object.
*/
this._parseEventChunk = function(chunk) {
if (!chunk || chunk.length === 0) {
return null;
}
var e = {'id': null, 'retry': null, 'data': '', 'event': 'message'};
chunk.split(/\n|\r\n|\r/).forEach(function(line) {
line = line.trimRight();
var index = line.indexOf(this.FIELD_SEPARATOR);
if (index <= 0) {
// Line was either empty, or started with a separator and is a comment.
// Either way, ignore.
return;
}
var field = line.substring(0, index);
if (!(field in e)) {
return;
}
var value = line.substring(index + 1).trimLeft();
if (field === 'data') {
e[field] += value;
} else {
e[field] = value;
}
}.bind(this));
var event = new CustomEvent(e.event);
event.data = e.data;
event.id = e.id;
return event;
};
this._checkStreamClosed = function() {
if (this.xhr.readyState === XMLHttpRequest.DONE) {
this._setReadyState(this.CLOSED);
}
};
this.stream = function() {
this._setReadyState(this.CONNECTING);
this.xhr = new XMLHttpRequest();
this.xhr.addEventListener('progress', this._onStreamProgress.bind(this));
this.xhr.addEventListener('load', this._onStreamLoaded.bind(this));
this.xhr.addEventListener('readystatechange', this._checkStreamClosed.bind(this));
this.xhr.addEventListener('error', this._onStreamFailure.bind(this));
this.xhr.addEventListener('abort', this._onStreamFailure.bind(this));
this.xhr.open(this.method, this.url);
for (var header in this.headers) {
this.xhr.setRequestHeader(header, this.headers[header]);
}
this.xhr.send(this.payload);
};
this.close = function() {
if (this.readyState === this.CLOSED) {
return;
}
this.xhr.abort();
this.xhr = null;
this._setReadyState(this.CLOSED);
};
};
// Export our SSE module for npm.js
if (typeof exports !== 'undefined') {
exports.SSE = SSE;
}