lib/_http_agent.js
// Copyright Joyent, Inc. and other Node contributors.
//
// 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';
var net = require('net');
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var debug = util.debuglog('http');
// New Agent code.
// The largest departure from the previous implementation is that
// an Agent instance holds connections for a variable number of host:ports.
// Surprisingly, this is still API compatible as far as third parties are
// concerned. The only code that really notices the difference is the
// request object.
// Another departure is that all code related to HTTP parsing is in
// ClientRequest.onSocket(). The Agent is now *strictly*
// concerned with managing a connection pool.
function Agent(options) {
if (!(this instanceof Agent))
return new Agent(options);
EventEmitter.call(this);
var self = this;
self.defaultPort = 80;
self.protocol = 'http:';
self.options = util._extend({}, options);
// don't confuse net and make it think that we're connecting to a pipe
self.options.path = null;
self.requests = {};
self.sockets = {};
self.freeSockets = {};
self.keepAliveMsecs = self.options.keepAliveMsecs || 1000;
self.keepAlive = self.options.keepAlive || false;
self.maxSockets = self.options.maxSockets || Agent.defaultMaxSockets;
self.maxFreeSockets = self.options.maxFreeSockets || 256;
self.on('free', function(socket, options) {
var name = self.getName(options);
debug('agent.on(free)', name);
if (!socket.destroyed &&
self.requests[name] && self.requests[name].length) {
self.requests[name].shift().onSocket(socket);
if (self.requests[name].length === 0) {
// don't leak
delete self.requests[name];
}
} else {
// If there are no pending requests, then put it in
// the freeSockets pool, but only if we're allowed to do so.
var req = socket._httpMessage;
if (req &&
req.shouldKeepAlive &&
!socket.destroyed &&
self.options.keepAlive) {
var freeSockets = self.freeSockets[name];
var freeLen = freeSockets ? freeSockets.length : 0;
var count = freeLen;
if (self.sockets[name])
count += self.sockets[name].length;
if (count >= self.maxSockets || freeLen >= self.maxFreeSockets) {
self.removeSocket(socket, options);
socket.destroy();
} else {
freeSockets = freeSockets || [];
self.freeSockets[name] = freeSockets;
socket.setKeepAlive(true, self.keepAliveMsecs);
socket.unref();
socket._httpMessage = null;
self.removeSocket(socket, options);
freeSockets.push(socket);
}
} else {
self.removeSocket(socket, options);
socket.destroy();
}
}
});
}
util.inherits(Agent, EventEmitter);
exports.Agent = Agent;
Agent.defaultMaxSockets = Infinity;
Agent.prototype.createConnection = net.createConnection;
// Get the key for a given set of request options
Agent.prototype.getName = function(options) {
var name = '';
if (options.host)
name += options.host;
else
name += 'localhost';
name += ':';
if (options.port)
name += options.port;
name += ':';
if (options.localAddress)
name += options.localAddress;
name += ':';
return name;
};
Agent.prototype.addRequest = function(req, options) {
// Legacy API: addRequest(req, host, port, path)
if (typeof options === 'string') {
options = {
host: options,
port: arguments[2],
path: arguments[3]
};
}
var name = this.getName(options);
if (!this.sockets[name]) {
this.sockets[name] = [];
}
var freeLen = this.freeSockets[name] ? this.freeSockets[name].length : 0;
var sockLen = freeLen + this.sockets[name].length;
if (freeLen) {
// we have a free socket, so use that.
var socket = this.freeSockets[name].shift();
debug('have free socket');
// don't leak
if (!this.freeSockets[name].length)
delete this.freeSockets[name];
socket.ref();
req.onSocket(socket);
this.sockets[name].push(socket);
} else if (sockLen < this.maxSockets) {
debug('call onSocket', sockLen, freeLen);
// If we are under maxSockets create a new one.
req.onSocket(this.createSocket(req, options));
} else {
debug('wait for socket');
// We are over limit so we'll add it to the queue.
if (!this.requests[name]) {
this.requests[name] = [];
}
this.requests[name].push(req);
}
};
Agent.prototype.createSocket = function(req, options) {
var self = this;
options = util._extend({}, options);
options = util._extend(options, self.options);
options.servername = options.host;
if (req) {
var hostHeader = req.getHeader('host');
if (hostHeader) {
options.servername = hostHeader.replace(/:.*$/, '');
}
}
var name = self.getName(options);
debug('createConnection', name, options);
options.encoding = null;
var s = self.createConnection(options);
if (!self.sockets[name]) {
self.sockets[name] = [];
}
this.sockets[name].push(s);
debug('sockets', name, this.sockets[name].length);
function onFree() {
self.emit('free', s, options);
}
s.on('free', onFree);
function onClose(err) {
debug('CLIENT socket onClose');
// This is the only place where sockets get removed from the Agent.
// If you want to remove a socket from the pool, just close it.
// All socket errors end in a close event anyway.
self.removeSocket(s, options);
}
s.on('close', onClose);
function onRemove() {
// We need this function for cases like HTTP 'upgrade'
// (defined by WebSockets) where we need to remove a socket from the
// pool because it'll be locked up indefinitely
debug('CLIENT socket onRemove');
self.removeSocket(s, options);
s.removeListener('close', onClose);
s.removeListener('free', onFree);
s.removeListener('agentRemove', onRemove);
}
s.on('agentRemove', onRemove);
return s;
};
Agent.prototype.removeSocket = function(s, options) {
var name = this.getName(options);
debug('removeSocket', name, 'destroyed:', s.destroyed);
var sets = [this.sockets];
// If the socket was destroyed, remove it from the free buffers too.
if (s.destroyed)
sets.push(this.freeSockets);
for (var sk = 0; sk < sets.length; sk++) {
var sockets = sets[sk];
if (sockets[name]) {
var index = sockets[name].indexOf(s);
if (index !== -1) {
sockets[name].splice(index, 1);
// Don't leak
if (sockets[name].length === 0)
delete sockets[name];
}
}
}
if (this.requests[name] && this.requests[name].length) {
debug('removeSocket, have a request, make a socket');
var req = this.requests[name][0];
// If we have pending requests and a socket gets closed make a new one
this.createSocket(req, options).emit('free');
}
};
Agent.prototype.destroy = function() {
var sets = [this.freeSockets, this.sockets];
for (var s = 0; s < sets.length; s++) {
var set = sets[s];
var keys = Object.keys(set);
for (var v = 0; v < keys.length; v++) {
var setName = set[keys[v]];
for (var n = 0; n < setName.length; n++) {
setName[n].destroy();
}
}
}
};
exports.globalAgent = new Agent();