lts/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';
const {
ObjectKeys,
ObjectSetPrototypeOf,
ObjectValues,
Symbol,
} = primordials;
const net = require('net');
const EventEmitter = require('events');
const debug = require('internal/util/debuglog').debuglog('http');
const { async_id_symbol } = require('internal/async_hooks').symbols;
const kOnKeylog = Symbol('onkeylog');
// 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.
class ReusedHandle {
constructor(type, handle) {
this.type = type;
this.handle = handle;
}
}
function freeSocketErrorListener(err) {
const socket = this;
debug('SOCKET ERROR on FREE socket:', err.message, err.stack);
socket.destroy();
socket.emit('agentRemove');
}
function Agent(options) {
if (!(this instanceof Agent))
return new Agent(options);
EventEmitter.call(this);
this.defaultPort = 80;
this.protocol = 'http:';
this.options = { ...options };
// Don't confuse net and make it think that we're connecting to a pipe
this.options.path = null;
this.requests = {};
this.sockets = {};
this.freeSockets = {};
this.keepAliveMsecs = this.options.keepAliveMsecs || 1000;
this.keepAlive = this.options.keepAlive || false;
this.maxSockets = this.options.maxSockets || Agent.defaultMaxSockets;
this.maxFreeSockets = this.options.maxFreeSockets || 256;
this.on('free', (socket, options) => {
const name = this.getName(options);
debug('agent.on(free)', name);
// TODO(ronag): socket.destroy(err) might have been called
// before coming here and have an 'error' scheduled. In the
// case of socket.destroy() below this 'error' has no handler
// and could cause unhandled exception.
if (socket.writable &&
this.requests[name] && this.requests[name].length) {
const req = this.requests[name].shift();
setRequestSocket(this, req, socket);
if (this.requests[name].length === 0) {
// don't leak
delete this.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.
const req = socket._httpMessage;
if (req &&
req.shouldKeepAlive &&
socket.writable &&
this.keepAlive) {
let freeSockets = this.freeSockets[name];
const freeLen = freeSockets ? freeSockets.length : 0;
let count = freeLen;
if (this.sockets[name])
count += this.sockets[name].length;
if (count > this.maxSockets || freeLen >= this.maxFreeSockets) {
socket.destroy();
} else if (this.keepSocketAlive(socket)) {
freeSockets = freeSockets || [];
this.freeSockets[name] = freeSockets;
socket[async_id_symbol] = -1;
socket._httpMessage = null;
this.removeSocket(socket, options);
const agentTimeout = this.options.timeout || 0;
if (socket.timeout !== agentTimeout) {
socket.setTimeout(agentTimeout);
}
socket.once('error', freeSocketErrorListener);
freeSockets.push(socket);
} else {
// Implementation doesn't want to keep socket alive
socket.destroy();
}
} else {
socket.destroy();
}
}
});
// Don't emit keylog events unless there is a listener for them.
this.on('newListener', maybeEnableKeylog);
}
ObjectSetPrototypeOf(Agent.prototype, EventEmitter.prototype);
ObjectSetPrototypeOf(Agent, EventEmitter);
function maybeEnableKeylog(eventName) {
if (eventName === 'keylog') {
this.removeListener('newListener', maybeEnableKeylog);
// Future sockets will listen on keylog at creation.
const agent = this;
this[kOnKeylog] = function onkeylog(keylog) {
agent.emit('keylog', keylog, this);
};
// Existing sockets will start listening on keylog now.
for (const socket of ObjectValues(this.sockets)) {
socket.on('keylog', this[kOnKeylog]);
}
}
}
Agent.defaultMaxSockets = Infinity;
Agent.prototype.createConnection = net.createConnection;
// Get the key for a given set of request options
Agent.prototype.getName = function getName(options) {
let name = options.host || 'localhost';
name += ':';
if (options.port)
name += options.port;
name += ':';
if (options.localAddress)
name += options.localAddress;
// Pacify parallel/test-http-agent-getname by only appending
// the ':' when options.family is set.
if (options.family === 4 || options.family === 6)
name += `:${options.family}`;
if (options.socketPath)
name += `:${options.socketPath}`;
return name;
};
Agent.prototype.addRequest = function addRequest(req, options, port/* legacy */,
localAddress/* legacy */) {
// Legacy API: addRequest(req, host, port, localAddress)
if (typeof options === 'string') {
options = {
host: options,
port,
localAddress
};
}
options = { ...options, ...this.options };
if (options.socketPath)
options.path = options.socketPath;
if (!options.servername && options.servername !== '')
options.servername = calculateServerName(options, req);
const name = this.getName(options);
if (!this.sockets[name]) {
this.sockets[name] = [];
}
const freeSockets = this.freeSockets[name];
let socket;
if (freeSockets) {
while (freeSockets.length && freeSockets[0].destroyed) {
freeSockets.shift();
}
socket = freeSockets.shift();
if (!freeSockets.length)
delete this.freeSockets[name];
}
const freeLen = freeSockets ? freeSockets.length : 0;
const sockLen = freeLen + this.sockets[name].length;
if (socket) {
// Guard against an uninitialized or user supplied Socket.
const handle = socket._handle;
if (handle && typeof handle.asyncReset === 'function') {
// Assign the handle a new asyncId and run any destroy()/init() hooks.
handle.asyncReset(new ReusedHandle(handle.getProviderType(), handle));
socket[async_id_symbol] = handle.getAsyncId();
}
this.reuseSocket(socket, req);
setRequestSocket(this, req, 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.
this.createSocket(req, options, handleSocketCreation(this, req, true));
} 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 createSocket(req, options, cb) {
options = { ...options, ...this.options };
if (options.socketPath)
options.path = options.socketPath;
if (!options.servername && options.servername !== '')
options.servername = calculateServerName(options, req);
const name = this.getName(options);
options._agentKey = name;
debug('createConnection', name, options);
options.encoding = null;
let called = false;
const oncreate = (err, s) => {
if (called)
return;
called = true;
if (err)
return cb(err);
if (!this.sockets[name]) {
this.sockets[name] = [];
}
this.sockets[name].push(s);
debug('sockets', name, this.sockets[name].length);
installListeners(this, s, options);
cb(null, s);
};
const newSocket = this.createConnection(options, oncreate);
if (newSocket)
oncreate(null, newSocket);
};
function calculateServerName(options, req) {
let servername = options.host;
const hostHeader = req.getHeader('host');
if (hostHeader) {
// abc => abc
// abc:123 => abc
// [::1] => ::1
// [::1]:123 => ::1
if (hostHeader.startsWith('[')) {
const index = hostHeader.indexOf(']');
if (index === -1) {
// Leading '[', but no ']'. Need to do something...
servername = hostHeader;
} else {
servername = hostHeader.substr(1, index - 1);
}
} else {
servername = hostHeader.split(':', 1)[0];
}
}
// Don't implicitly set invalid (IP) servernames.
if (net.isIP(servername))
servername = '';
return servername;
}
function installListeners(agent, s, options) {
function onFree() {
debug('CLIENT socket onFree');
agent.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.
agent.removeSocket(s, options);
}
s.on('close', onClose);
function onTimeout() {
debug('CLIENT socket onTimeout');
// Destroy if in free list.
// TODO(ronag): Always destroy, even if not in free list.
const sockets = agent.freeSockets;
for (const name of ObjectKeys(sockets)) {
if (sockets[name].includes(s)) {
return s.destroy();
}
}
}
s.on('timeout', onTimeout);
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');
agent.removeSocket(s, options);
s.removeListener('close', onClose);
s.removeListener('free', onFree);
s.removeListener('timeout', onTimeout);
s.removeListener('agentRemove', onRemove);
}
s.on('agentRemove', onRemove);
if (agent[kOnKeylog]) {
s.on('keylog', agent[kOnKeylog]);
}
}
Agent.prototype.removeSocket = function removeSocket(s, options) {
const name = this.getName(options);
debug('removeSocket', name, 'writable:', s.writable);
const sets = [this.sockets];
// If the socket was destroyed, remove it from the free buffers too.
if (!s.writable)
sets.push(this.freeSockets);
for (const sockets of sets) {
if (sockets[name]) {
const 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');
const req = this.requests[name][0];
// If we have pending requests and a socket gets closed make a new one
const socketCreationHandler = handleSocketCreation(this, req, false);
this.createSocket(req, options, socketCreationHandler);
}
};
Agent.prototype.keepSocketAlive = function keepSocketAlive(socket) {
socket.setKeepAlive(true, this.keepAliveMsecs);
socket.unref();
return true;
};
Agent.prototype.reuseSocket = function reuseSocket(socket, req) {
debug('have free socket');
socket.removeListener('error', freeSocketErrorListener);
req.reusedSocket = true;
socket.ref();
};
Agent.prototype.destroy = function destroy() {
for (const set of [this.freeSockets, this.sockets]) {
for (const key of ObjectKeys(set)) {
for (const setName of set[key]) {
setName.destroy();
}
}
}
};
function handleSocketCreation(agent, request, informRequest) {
return function handleSocketCreation_Inner(err, socket) {
if (err) {
process.nextTick(emitErrorNT, request, err);
return;
}
if (informRequest)
setRequestSocket(agent, request, socket);
else
socket.emit('free');
};
}
function setRequestSocket(agent, req, socket) {
req.onSocket(socket);
const agentTimeout = agent.options.timeout || 0;
if (req.timeout === undefined || req.timeout === agentTimeout) {
return;
}
socket.setTimeout(req.timeout);
}
function emitErrorNT(emitter, err) {
emitter.emit('error', err);
}
module.exports = {
Agent,
globalAgent: new Agent()
};