/
stream_listener.js
185 lines (162 loc) · 5.26 KB
/
stream_listener.js
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var StreamListener = (function() {
var props = {
streamReconnectCount: 0,
streamReconnectBaseTime: 20000,
streamReconnectWaitTime: this.streamReconnectBaseTime,
streamMaxStaleTime: 90000,
streamMaxReconnectWait: 240000
};
props.subscribers = [];
props.twitterLib = null;
var curry = function(func) {
var slice = Array.prototype.slice, args = slice.call(arguments, 1);
return function() {
func.apply(this, args.concat(slice.call(arguments)));
};
};
var publish = function(data) {
if(props.twitterLib) {
if(data.hasOwnProperty('text')) {
props.twitterLib.normalizeTweets(data);
} else if(data.hasOwnProperty('direct_message')) {
props.twitterLib.normalizeTweets(data.direct_message);
}
}
console.log(data);
for(var i = 0, len = props.subscribers.length; i < len; ++i) {
var sub = props.subscribers[i];
sub.callback.call(sub.context, data);
}
};
var publishDisconnect = curry(publish, {
event: 'disconnected'
});
var xhr, onProgress;
var stopStream = function() {
if(!xhr) {
return;
}
xhr.removeEventListener("progress", onProgress, false);
xhr.abort();
};
var connectStream = function() {
if(!OptionsBackend.get('use_streaming_api')) {
return;
}
var MAX_BUFFER = 1024 * 500;
var url = OptionsBackend.get('user_stream_url');
var params = {
delimited: 'length'
};
props.streamReconnectCount += 1;
console.log('connecting to stream ', props.streamReconnectCount);
xhr = new XMLHttpRequest();
xhr.open('GET', url + '?' + $.param(params), true);
xhr.setRequestHeader('X-User-Agent', 'Chromed Bird ' + JSON.parse(Persistence.version().val()).join('.'));
if(props.twitterLib) {
props.twitterLib.signOauth(xhr, url, params, 'GET');
}
var lastLoaded = 0, lastChunkLen, lastProgressTime = new Date().getTime();
onProgress = function(e) {
console.log('loaded', e.loaded, 'time', new Date().getTime() - lastProgressTime);
lastProgressTime = new Date().getTime();
var totalLen = e.loaded;
if(totalLen > MAX_BUFFER) {
console.log('stream disconnected, buffer too large');
stopStream();
}
var data = xhr.responseText;
while(lastLoaded < totalLen) {
if(!lastChunkLen) {
lastChunkLen = '';
var curChar = data.charAt(lastLoaded);
while(curChar != '\n' || lastChunkLen.length === 0) {
if(curChar.match(/\d/)) {
lastChunkLen += curChar;
}
lastLoaded += 1;
if(lastLoaded >= totalLen) {
return;
}
curChar = data.charAt(lastLoaded);
}
lastLoaded += 1;
lastChunkLen = parseInt(lastChunkLen, 10);
}
if(lastLoaded + lastChunkLen > totalLen) {
// Let's just wait for the rest of our data
return;
}
var jsonChunk = data.substring(lastLoaded, lastLoaded + lastChunkLen);
var parsedChunk = JSON.parse(jsonChunk);
publish(parsedChunk);
lastLoaded += lastChunkLen;
lastChunkLen = null;
}
};
xhr.addEventListener("progress", onProgress, false);
var intervalHandle;
xhr.onreadystatechange = function() {
if(xhr.readyState == 2 && xhr.status == 200) {
console.log('stream connected ok');
var checkStaleConnection = function() {
var time = new Date().getTime();
if(time - lastProgressTime > props.streamMaxStaleTime) {
console.log('stream stale connection');
stopStream();
}
};
intervalHandle = setInterval(checkStaleConnection, props.streamMaxStaleTime / 2);
props.streamReconnectWaitTime = props.streamReconnectBaseTime;
} else if(xhr.readyState == 4) {
console.log('stream disconnected', xhr.status, xhr.statusText);
publishDisconnect();
if(intervalHandle) {
clearInterval(intervalHandle);
intervalHandle = null;
}
if(props.twitterLib) {
setTimeout(function() {
connectStream();
}, props.streamReconnectWaitTime);
if(props.streamReconnectWaitTime < props.streamMaxReconnectWait) {
props.streamReconnectWaitTime *= 2;
}
}
}
};
xhr.send();
};
return {
events: {
DISCONNECTED: 'disconnected'
},
start: function(twitterLib) {
props.twitterLib = twitterLib;
connectStream();
},
disconnect: function() {
props.twitterLib = null;
props.subscribers = [];
stopStream();
},
unsubscribe: function(context) {
console.log('unsubscribe: ' + context.template.id);
var newSubscribers = [];
for(var i = 0, len = props.subscribers.length; i < len; ++i) {
var sub = props.subscribers[i];
if(sub.context != context) {
newSubscribers.push(sub);
}
}
props.subscribers = newSubscribers;
},
subscribe: function(callbackOrOptions, context) {
var options = (typeof callbackOrOptions === 'function') ? {
callback: callbackOrOptions,
context: context
} : callbackOrOptions;
props.subscribers.push(options);
}
};
}).call({});