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July 2, 2013 13:09
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js: ajax & nodejs long polling
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// Client.js | |
var Socket = function(ip, port, name) { | |
this.ip = ip; | |
this.port = port; | |
this.name = name; | |
this._cbs = []; | |
this._poll(); | |
}; | |
// Call the server periodically for data. | |
Socket.prototype._poll = function() { | |
var that = this; | |
// if the server does not return then call it again | |
var timer = setTimeout(function() { | |
this._poll(); | |
}, 5000); | |
$.ajax({ | |
type: "GET", | |
timeout: 5000, | |
data: { | |
name: this.name | |
}, | |
url: this.ip + ":" + this.port, | |
success: function(data) { | |
// server returned, kill the timer. | |
clearTimeout(timer); | |
// send the message to the callback. | |
for (var i = 0; i < that._cbs.length; i++) { | |
that._cbs[i](data); | |
} | |
// call the server again | |
that._poll(); | |
} | |
}); | |
}; | |
// Add a callback for a message event | |
Socket.prototype.on = function(event, cb) { | |
if (event === "message") { | |
this._cbs.push(cb); | |
} | |
}; | |
// Send a message to the server | |
Socket.prototype.send = function(message) { | |
$.ajax({ | |
data: { | |
message: message, | |
name: this.name | |
}, | |
type: "GET", | |
url: this.ip + ":" + this.port | |
}); | |
}; | |
var socket = new Socket('192.168.1.1', '8081', "Raynos"); | |
socket.on("message", function(data) { | |
console.log(data); | |
}); | |
socket.send("Hello world!"); | |
// server.js | |
var url = require("url"); | |
var events = require("events"); | |
// store messages for clients | |
var clients = {}; | |
var emitter = new events.EventEmitter(); | |
http.createServer(function(req, res) { | |
// get query string data | |
var data = url.parse(req.url, true).query; | |
// if client is not initialized then initialize it. | |
if (data.name && !clients[data.name]) { | |
clients[data.name] = []; | |
} | |
// if you posted a message then add it to all arrays | |
if (data.message) { | |
for (var k in clients) { | |
clients[k].push(data.name + " : " + data.message); | |
} | |
// tell long pollers to flush new data. | |
emitter.emit("new-data"); | |
} else if (clients[data.name].length > 0) { | |
// else empty the clients array down the stream | |
for (var i = 0; i < clients[data.name].length; i++) { | |
res.write(clients[data.name].shift()); | |
}; | |
res.end(); | |
// long polling magic. | |
} else { | |
var cb = function() { | |
for (var i = 0; i < clients[data.name].length; i++) { | |
res.write(clients[data.name].shift()); | |
}; | |
res.end(); | |
// kill that timer for the response timing out. | |
clearTimeout(timer); | |
} | |
// when we get data flush it to client | |
emitter.once("new-data", cb); | |
var timer = setTimeout(function() { | |
// too long has passed so remove listener and end response. | |
emitter.removeListener(cb); | |
res.end(); | |
}, 4500); | |
} | |
}).listen(8081); |
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同时发过来两个请求的话,这个 emitter 是不是会搞混=。=