diff --git a/doc/api/net.markdown b/doc/api/net.markdown index 7b328adeab..c2d8fb3e7c 100644 --- a/doc/api/net.markdown +++ b/doc/api/net.markdown @@ -6,176 +6,82 @@ The `net` module provides you with an asynchronous network wrapper. It contains functions for creating both servers and clients (called streams). You can include this module with `require('net');`. -## net.createServer([options][, connectionListener]) - -Creates a new server. The `connectionListener` argument is -automatically set as a listener for the ['connection'][] event. - -`options` is an object with the following defaults: - - { - allowHalfOpen: false, - pauseOnConnect: false - } +## Class: net.Server -If `allowHalfOpen` is `true`, then the socket won't automatically send a FIN -packet when the other end of the socket sends a FIN packet. The socket becomes -non-readable, but still writable. You should call the `end()` method explicitly. -See ['end'][] event for more information. +This class is used to create a TCP or local server. -If `pauseOnConnect` is `true`, then the socket associated with each incoming -connection will be paused, and no data will be read from its handle. This allows -connections to be passed between processes without any data being read by the -original process. To begin reading data from a paused socket, call `resume()`. +`net.Server` is an [EventEmitter][] with the following events: -Here is an example of an echo server which listens for connections -on port 8124: +### Event: 'close' - var net = require('net'); - var server = net.createServer(function(c) { //'connection' listener - console.log('client connected'); - c.on('end', function() { - console.log('client disconnected'); - }); - c.write('hello\r\n'); - c.pipe(c); - }); - server.listen(8124, function() { //'listening' listener - console.log('server bound'); - }); +Emitted when the server closes. Note that if connections exist, this +event is not emitted until all connections are ended. -Test this by using `telnet`: +### Event: 'connection' - telnet localhost 8124 +* {Socket object} The connection object -To listen on the socket `/tmp/echo.sock` the third line from the last would -just be changed to +Emitted when a new connection is made. `socket` is an instance of +`net.Socket`. - server.listen('/tmp/echo.sock', function() { //'listening' listener +### Event: 'error' -Use `nc` to connect to a UNIX domain socket server: +* {Error Object} - nc -U /tmp/echo.sock +Emitted when an error occurs. The ['close'][] event will be called directly +following this event. See example in discussion of `server.listen`. -## net.connect(options[, connectListener]) -## net.createConnection(options[, connectListener]) +### Event: 'listening' -A factory function, which returns a new ['net.Socket'](#net_class_net_socket) -and automatically connects with the supplied `options`. +Emitted when the server has been bound after calling `server.listen`. -The options are passed to both the ['net.Socket'](#net_class_net_socket) -constructor and the ['socket.connect'](#net_socket_connect_options_connectlistener) -method. +### server.address() -The `connectListener` parameter will be added as a listener for the -['connect'][] event once. +Returns the bound address, the address family name and port of the server +as reported by the operating system. +Useful to find which port was assigned when giving getting an OS-assigned address. +Returns an object with three properties, e.g. +`{ port: 12346, family: 'IPv4', address: '127.0.0.1' }` -Here is an example of a client of the previously described echo server: +Example: - var net = require('net'); - var client = net.connect({port: 8124}, - function() { //'connect' listener - console.log('connected to server!'); - client.write('world!\r\n'); - }); - client.on('data', function(data) { - console.log(data.toString()); - client.end(); - }); - client.on('end', function() { - console.log('disconnected from server'); + var server = net.createServer(function (socket) { + socket.end("goodbye\n"); }); -To connect on the socket `/tmp/echo.sock` the second line would just be -changed to - - var client = net.connect({path: '/tmp/echo.sock'}); - -## net.connect(port[, host][, connectListener]) -## net.createConnection(port[, host][, connectListener]) - -A factory function, which returns a new -['net.Socket'](#net_class_net_socket) and automatically connects to the -supplied `port` and `host`. - -If `host` is omitted, `'localhost'` will be assumed. - -The `connectListener` parameter will be added as a listener for the -['connect'][] event once. - -## net.connect(path[, connectListener]) -## net.createConnection(path[, connectListener]) - -A factory function, which returns a new unix -['net.Socket'](#net_class_net_socket) and automatically connects to the -supplied `path`. - -The `connectListener` parameter will be added as a listener for the -['connect'][] event once. - -## Class: net.Server - -This class is used to create a TCP or local server. - -### server.listen(port[, hostname][, backlog][, callback]) - -Begin accepting connections on the specified `port` and `hostname`. If the -`hostname` is omitted, the server will accept connections on any IPv6 address -(`::`) when IPv6 is available, or any IPv4 address (`0.0.0.0`) otherwise. A -port value of zero will assign a random port. - -Backlog is the maximum length of the queue of pending connections. -The actual length will be determined by your OS through sysctl settings such as -`tcp_max_syn_backlog` and `somaxconn` on linux. The default value of this -parameter is 511 (not 512). - -This function is asynchronous. When the server has been bound, -['listening'][] event will be emitted. The last parameter `callback` -will be added as a listener for the ['listening'][] event. - -One issue some users run into is getting `EADDRINUSE` errors. This means that -another server is already running on the requested port. One way of handling this -would be to wait a second and then try again. This can be done with - - server.on('error', function (e) { - if (e.code == 'EADDRINUSE') { - console.log('Address in use, retrying...'); - setTimeout(function () { - server.close(); - server.listen(PORT, HOST); - }, 1000); - } + // grab a random port. + server.listen(function() { + address = server.address(); + console.log("opened server on %j", address); }); -(Note: All sockets in Node.js set `SO_REUSEADDR` already) +Don't call `server.address()` until the `'listening'` event has been emitted. +### server.close([callback]) -### server.listen(path[, callback]) +Stops the server from accepting new connections and keeps existing +connections. This function is asynchronous, the server is finally +closed when all connections are ended and the server emits a ['close'][] event. +The optional `callback` will be called once the `'close'` event occurs. Unlike +that event, it will be called with an Error as its only argument if the server +was not open when it was closed. -* `path` {String} -* `callback` {Function} +### server.connections -Start a local socket server listening for connections on the given `path`. + Stability: 0 - Deprecated: Use [server.getConnections][] instead. -This function is asynchronous. When the server has been bound, -['listening'][] event will be emitted. The last parameter `callback` -will be added as a listener for the ['listening'][] event. +The number of concurrent connections on the server. -On UNIX, the local domain is usually known as the UNIX domain. The path is a -filesystem path name. It is subject to the same naming conventions and -permissions checks as would be done on file creation, will be visible in the -filesystem, and will *persist until unlinked*. +This becomes `null` when sending a socket to a child with +`child_process.fork()`. To poll forks and get current number of active +connections use asynchronous `server.getConnections` instead. -On Windows, the local domain is implemented using a named pipe. The path *must* -refer to an entry in `\\?\pipe\` or `\\.\pipe\`. Any characters are permitted, -but the latter may do some processing of pipe names, such as resolving `..` -sequences. Despite appearances, the pipe name space is flat. Pipes will *not -persist*, they are removed when the last reference to them is closed. Do not -forget JavaScript string escaping requires paths to be specified with -double-backslashes, such as: +### server.getConnections(callback) - net.createServer().listen( - path.join('\\\\?\\pipe', process.cwd(), 'myctl')) +Asynchronously get the number of concurrent connections on the server. Works +when sockets were sent to forks. + +Callback should take two arguments `err` and `count`. ### server.listen(handle[, callback]) @@ -224,52 +130,64 @@ shown below. exclusive: true }); -### server.close([callback]) +### server.listen(path[, callback]) -Stops the server from accepting new connections and keeps existing -connections. This function is asynchronous, the server is finally -closed when all connections are ended and the server emits a ['close'][] event. -The optional `callback` will be called once the `'close'` event occurs. Unlike -that event, it will be called with an Error as its only argument if the server -was not open when it was closed. +* `path` {String} +* `callback` {Function} -### server.address() +Start a local socket server listening for connections on the given `path`. -Returns the bound address, the address family name and port of the server -as reported by the operating system. -Useful to find which port was assigned when giving getting an OS-assigned address. -Returns an object with three properties, e.g. -`{ port: 12346, family: 'IPv4', address: '127.0.0.1' }` +This function is asynchronous. When the server has been bound, +['listening'][] event will be emitted. The last parameter `callback` +will be added as a listener for the ['listening'][] event. -Example: +On UNIX, the local domain is usually known as the UNIX domain. The path is a +filesystem path name. It is subject to the same naming conventions and +permissions checks as would be done on file creation, will be visible in the +filesystem, and will *persist until unlinked*. - var server = net.createServer(function (socket) { - socket.end("goodbye\n"); - }); +On Windows, the local domain is implemented using a named pipe. The path *must* +refer to an entry in `\\?\pipe\` or `\\.\pipe\`. Any characters are permitted, +but the latter may do some processing of pipe names, such as resolving `..` +sequences. Despite appearances, the pipe name space is flat. Pipes will *not +persist*, they are removed when the last reference to them is closed. Do not +forget JavaScript string escaping requires paths to be specified with +double-backslashes, such as: - // grab a random port. - server.listen(function() { - address = server.address(); - console.log("opened server on %j", address); - }); + net.createServer().listen( + path.join('\\\\?\\pipe', process.cwd(), 'myctl')) -Don't call `server.address()` until the `'listening'` event has been emitted. +### server.listen(port[, hostname][, backlog][, callback]) -### server.unref() +Begin accepting connections on the specified `port` and `hostname`. If the +`hostname` is omitted, the server will accept connections on any IPv6 address +(`::`) when IPv6 is available, or any IPv4 address (`0.0.0.0`) otherwise. A +port value of zero will assign a random port. -Calling `unref` on a server will allow the program to exit if this is the only -active server in the event system. If the server is already `unref`d calling -`unref` again will have no effect. +Backlog is the maximum length of the queue of pending connections. +The actual length will be determined by your OS through sysctl settings such as +`tcp_max_syn_backlog` and `somaxconn` on linux. The default value of this +parameter is 511 (not 512). -Returns `server`. +This function is asynchronous. When the server has been bound, +['listening'][] event will be emitted. The last parameter `callback` +will be added as a listener for the ['listening'][] event. -### server.ref() +One issue some users run into is getting `EADDRINUSE` errors. This means that +another server is already running on the requested port. One way of handling this +would be to wait a second and then try again. This can be done with -Opposite of `unref`, calling `ref` on a previously `unref`d server will *not* -let the program exit if it's the only server left (the default behavior). If -the server is `ref`d calling `ref` again will have no effect. + server.on('error', function (e) { + if (e.code == 'EADDRINUSE') { + console.log('Address in use, retrying...'); + setTimeout(function () { + server.close(); + server.listen(PORT, HOST); + }, 1000); + } + }); -Returns `server`. +(Note: All sockets in Node.js set `SO_REUSEADDR` already) ### server.maxConnections @@ -279,47 +197,21 @@ high. It is not recommended to use this option once a socket has been sent to a child with `child_process.fork()`. -### server.connections - - Stability: 0 - Deprecated: Use [server.getConnections][] instead. - -The number of concurrent connections on the server. - -This becomes `null` when sending a socket to a child with -`child_process.fork()`. To poll forks and get current number of active -connections use asynchronous `server.getConnections` instead. - -### server.getConnections(callback) - -Asynchronously get the number of concurrent connections on the server. Works -when sockets were sent to forks. - -Callback should take two arguments `err` and `count`. - -`net.Server` is an [EventEmitter][] with the following events: - -### Event: 'listening' - -Emitted when the server has been bound after calling `server.listen`. - -### Event: 'connection' - -* {Socket object} The connection object - -Emitted when a new connection is made. `socket` is an instance of -`net.Socket`. +### server.ref() -### Event: 'close' +Opposite of `unref`, calling `ref` on a previously `unref`d server will *not* +let the program exit if it's the only server left (the default behavior). If +the server is `ref`d calling `ref` again will have no effect. -Emitted when the server closes. Note that if connections exist, this -event is not emitted until all connections are ended. +Returns `server`. -### Event: 'error' +### server.unref() -* {Error Object} +Calling `unref` on a server will allow the program to exit if this is the only +active server in the event system. If the server is already `unref`d calling +`unref` again will have no effect. -Emitted when an error occurs. The ['close'][] event will be called directly -following this event. See example in discussion of `server.listen`. +Returns `server`. ## Class: net.Socket @@ -345,44 +237,76 @@ Set `readable` and/or `writable` to `true` to allow reads and/or writes on this socket (NOTE: Works only when `fd` is passed). About `allowHalfOpen`, refer to `createServer()` and `'end'` event. -### socket.connect(options[, connectListener]) +`net.Socket` instances are [EventEmitter][] with the following events: -Opens the connection for a given socket. +### Event: 'close' -For TCP sockets, `options` argument should be an object which specifies: +* `had_error` {Boolean} `true` if the socket had a transmission error. - - `port`: Port the client should connect to (Required). +Emitted once the socket is fully closed. The argument `had_error` is a boolean +which says if the socket was closed due to a transmission error. - - `host`: Host the client should connect to. Defaults to `'localhost'`. +### Event: 'connect' - - `localAddress`: Local interface to bind to for network connections. +Emitted when a socket connection is successfully established. +See `connect()`. - - `localPort`: Local port to bind to for network connections. +### Event: 'data' - - `family` : Version of IP stack. Defaults to `4`. +* {Buffer object} - - `lookup` : Custom lookup function. Defaults to `dns.lookup`. +Emitted when data is received. The argument `data` will be a `Buffer` or +`String`. Encoding of data is set by `socket.setEncoding()`. +(See the [Readable Stream][] section for more information.) -For local domain sockets, `options` argument should be an object which -specifies: +Note that the __data will be lost__ if there is no listener when a `Socket` +emits a `'data'` event. - - `path`: Path the client should connect to (Required). +### Event: 'drain' -Normally this method is not needed, as `net.createConnection` opens the -socket. Use this only if you are implementing a custom Socket. +Emitted when the write buffer becomes empty. Can be used to throttle uploads. -This function is asynchronous. When the ['connect'][] event is emitted the -socket is established. If there is a problem connecting, the `'connect'` event -will not be emitted, the `'error'` event will be emitted with the exception. +See also: the return values of `socket.write()` -The `connectListener` parameter will be added as a listener for the -['connect'][] event. +### Event: 'end' -### socket.connect(port[, host][, connectListener]) -### socket.connect(path[, connectListener]) +Emitted when the other end of the socket sends a FIN packet. -As [socket.connect(options[, connectListener])](#net_socket_connect_options_connectlistener), -with options either as either `{port: port, host: host}` or `{path: path}`. +By default (`allowHalfOpen == false`) the socket will destroy its file +descriptor once it has written out its pending write queue. However, by +setting `allowHalfOpen == true` the socket will not automatically `end()` +its side allowing the user to write arbitrary amounts of data, with the +caveat that the user is required to `end()` their side now. + +### Event: 'error' + +* {Error object} + +Emitted when an error occurs. The `'close'` event will be called directly +following this event. + +### Event: 'lookup' + +Emitted after resolving the hostname but before connecting. +Not applicable to UNIX sockets. + +* `err` {Error | Null} The error object. See [dns.lookup()][]. +* `address` {String} The IP address. +* `family` {String | Null} The address type. See [dns.lookup()][]. + +### Event: 'timeout' + +Emitted if the socket times out from inactivity. This is only to notify that +the socket has been idle. The user must manually close the connection. + +See also: `socket.setTimeout()` + +### socket.address() + +Returns the bound address, the address family name and port of the +socket as reported by the operating system. Returns an object with +three properties, e.g. +`{ port: 12346, family: 'IPv4', address: '127.0.0.1' }` ### socket.bufferSize @@ -402,23 +326,57 @@ encoded, so the exact number of bytes is not known.) Users who experience large or growing `bufferSize` should attempt to "throttle" the data flows in their program with `pause()` and `resume()`. +### socket.bytesRead -### socket.setEncoding([encoding]) +The amount of received bytes. -Set the encoding for the socket as a Readable Stream. See -[stream.setEncoding()][] for more information. +### socket.bytesWritten -### socket.write(data[, encoding][, callback]) +The amount of bytes sent. -Sends data on the socket. The second parameter specifies the encoding in the -case of a string--it defaults to UTF8 encoding. +### socket.connect(options[, connectListener]) -Returns `true` if the entire data was flushed successfully to the kernel -buffer. Returns `false` if all or part of the data was queued in user memory. -`'drain'` will be emitted when the buffer is again free. +Opens the connection for a given socket. -The optional `callback` parameter will be executed when the data is finally -written out - this may not be immediately. +For TCP sockets, `options` argument should be an object which specifies: + + - `port`: Port the client should connect to (Required). + + - `host`: Host the client should connect to. Defaults to `'localhost'`. + + - `localAddress`: Local interface to bind to for network connections. + + - `localPort`: Local port to bind to for network connections. + + - `family` : Version of IP stack. Defaults to `4`. + + - `lookup` : Custom lookup function. Defaults to `dns.lookup`. + +For local domain sockets, `options` argument should be an object which +specifies: + + - `path`: Path the client should connect to (Required). + +Normally this method is not needed, as `net.createConnection` opens the +socket. Use this only if you are implementing a custom Socket. + +This function is asynchronous. When the ['connect'][] event is emitted the +socket is established. If there is a problem connecting, the `'connect'` event +will not be emitted, the `'error'` event will be emitted with the exception. + +The `connectListener` parameter will be added as a listener for the +['connect'][] event. + +### socket.connect(path[, connectListener]) +### socket.connect(port[, host][, connectListener]) + +As [socket.connect(options[, connectListener])](#net_socket_connect_options_connectlistener), +with options either as either `{port: port, host: host}` or `{path: path}`. + +### socket.destroy() + +Ensures that no more I/O activity happens on this socket. Only necessary in +case of errors (parse error or so). ### socket.end([data][, encoding]) @@ -428,44 +386,52 @@ server will still send some data. If `data` is specified, it is equivalent to calling `socket.write(data, encoding)` followed by `socket.end()`. -### socket.destroy() +### socket.localAddress -Ensures that no more I/O activity happens on this socket. Only necessary in -case of errors (parse error or so). +The string representation of the local IP address the remote client is +connecting on. For example, if you are listening on `'0.0.0.0'` and the +client connects on `'192.168.1.1'`, the value would be `'192.168.1.1'`. + +### socket.localPort + +The numeric representation of the local port. For example, +`80` or `21`. ### socket.pause() Pauses the reading of data. That is, `'data'` events will not be emitted. Useful to throttle back an upload. -### socket.resume() +### socket.ref() -Resumes reading after a call to `pause()`. +Opposite of `unref`, calling `ref` on a previously `unref`d socket will *not* +let the program exit if it's the only socket left (the default behavior). If +the socket is `ref`d calling `ref` again will have no effect. -### socket.setTimeout(timeout[, callback]) +Returns `socket`. -Sets the socket to timeout after `timeout` milliseconds of inactivity on -the socket. By default `net.Socket` do not have a timeout. +### socket.remoteAddress -When an idle timeout is triggered the socket will receive a `'timeout'` -event but the connection will not be severed. The user must manually `end()` -or `destroy()` the socket. +The string representation of the remote IP address. For example, +`'74.125.127.100'` or `'2001:4860:a005::68'`. -If `timeout` is 0, then the existing idle timeout is disabled. +### socket.remoteFamily -The optional `callback` parameter will be added as a one time listener for the -`'timeout'` event. +The string representation of the remote IP family. `'IPv4'` or `'IPv6'`. -Returns `socket`. +### socket.remotePort -### socket.setNoDelay([noDelay]) +The numeric representation of the remote port. For example, +`80` or `21`. -Disables the Nagle algorithm. By default TCP connections use the Nagle -algorithm, they buffer data before sending it off. Setting `true` for -`noDelay` will immediately fire off data each time `socket.write()` is called. -`noDelay` defaults to `true`. +### socket.resume() -Returns `socket`. +Resumes reading after a call to `pause()`. + +### socket.setEncoding([encoding]) + +Set the encoding for the socket as a Readable Stream. See +[stream.setEncoding()][] for more information. ### socket.setKeepAlive([enable][, initialDelay]) @@ -480,12 +446,30 @@ initialDelay will leave the value unchanged from the default Returns `socket`. -### socket.address() +### socket.setNoDelay([noDelay]) -Returns the bound address, the address family name and port of the -socket as reported by the operating system. Returns an object with -three properties, e.g. -`{ port: 12346, family: 'IPv4', address: '127.0.0.1' }` +Disables the Nagle algorithm. By default TCP connections use the Nagle +algorithm, they buffer data before sending it off. Setting `true` for +`noDelay` will immediately fire off data each time `socket.write()` is called. +`noDelay` defaults to `true`. + +Returns `socket`. + +### socket.setTimeout(timeout[, callback]) + +Sets the socket to timeout after `timeout` milliseconds of inactivity on +the socket. By default `net.Socket` do not have a timeout. + +When an idle timeout is triggered the socket will receive a `'timeout'` +event but the connection will not be severed. The user must manually `end()` +or `destroy()` the socket. + +If `timeout` is 0, then the existing idle timeout is disabled. + +The optional `callback` parameter will be added as a one time listener for the +`'timeout'` event. + +Returns `socket`. ### socket.unref() @@ -495,113 +479,174 @@ active socket in the event system. If the socket is already `unref`d calling Returns `socket`. -### socket.ref() +### socket.write(data[, encoding][, callback]) -Opposite of `unref`, calling `ref` on a previously `unref`d socket will *not* -let the program exit if it's the only socket left (the default behavior). If -the socket is `ref`d calling `ref` again will have no effect. +Sends data on the socket. The second parameter specifies the encoding in the +case of a string--it defaults to UTF8 encoding. -Returns `socket`. +Returns `true` if the entire data was flushed successfully to the kernel +buffer. Returns `false` if all or part of the data was queued in user memory. +`'drain'` will be emitted when the buffer is again free. -### socket.remoteAddress +The optional `callback` parameter will be executed when the data is finally +written out - this may not be immediately. -The string representation of the remote IP address. For example, -`'74.125.127.100'` or `'2001:4860:a005::68'`. +## net.connect(options[, connectListener]) -### socket.remoteFamily +A factory function, which returns a new ['net.Socket'](#net_class_net_socket) +and automatically connects with the supplied `options`. -The string representation of the remote IP family. `'IPv4'` or `'IPv6'`. +The options are passed to both the ['net.Socket'](#net_class_net_socket) +constructor and the ['socket.connect'](#net_socket_connect_options_connectlistener) +method. -### socket.remotePort +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -The numeric representation of the remote port. For example, -`80` or `21`. +Here is an example of a client of the previously described echo server: -### socket.localAddress + var net = require('net'); + var client = net.connect({port: 8124}, + function() { //'connect' listener + console.log('connected to server!'); + client.write('world!\r\n'); + }); + client.on('data', function(data) { + console.log(data.toString()); + client.end(); + }); + client.on('end', function() { + console.log('disconnected from server'); + }); -The string representation of the local IP address the remote client is -connecting on. For example, if you are listening on `'0.0.0.0'` and the -client connects on `'192.168.1.1'`, the value would be `'192.168.1.1'`. +To connect on the socket `/tmp/echo.sock` the second line would just be +changed to -### socket.localPort + var client = net.connect({path: '/tmp/echo.sock'}); -The numeric representation of the local port. For example, -`80` or `21`. +## net.connect(path[, connectListener]) -### socket.bytesRead +A factory function, which returns a new unix +['net.Socket'](#net_class_net_socket) and automatically connects to the +supplied `path`. -The amount of received bytes. +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -### socket.bytesWritten +## net.connect(port[, host][, connectListener]) -The amount of bytes sent. +A factory function, which returns a new +['net.Socket'](#net_class_net_socket) and automatically connects to the +supplied `port` and `host`. +If `host` is omitted, `'localhost'` will be assumed. -`net.Socket` instances are [EventEmitter][] with the following events: +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -### Event: 'lookup' +## net.createConnection(options[, connectListener]) -Emitted after resolving the hostname but before connecting. -Not applicable to UNIX sockets. +A factory function, which returns a new ['net.Socket'](#net_class_net_socket) +and automatically connects with the supplied `options`. -* `err` {Error | Null} The error object. See [dns.lookup()][]. -* `address` {String} The IP address. -* `family` {String | Null} The address type. See [dns.lookup()][]. +The options are passed to both the ['net.Socket'](#net_class_net_socket) +constructor and the ['socket.connect'](#net_socket_connect_options_connectlistener) +method. -### Event: 'connect' +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -Emitted when a socket connection is successfully established. -See `connect()`. +Here is an example of a client of the previously described echo server: -### Event: 'data' + var net = require('net'); + var client = net.connect({port: 8124}, + function() { //'connect' listener + console.log('connected to server!'); + client.write('world!\r\n'); + }); + client.on('data', function(data) { + console.log(data.toString()); + client.end(); + }); + client.on('end', function() { + console.log('disconnected from server'); + }); -* {Buffer object} +To connect on the socket `/tmp/echo.sock` the second line would just be +changed to -Emitted when data is received. The argument `data` will be a `Buffer` or -`String`. Encoding of data is set by `socket.setEncoding()`. -(See the [Readable Stream][] section for more information.) + var client = net.connect({path: '/tmp/echo.sock'}); -Note that the __data will be lost__ if there is no listener when a `Socket` -emits a `'data'` event. +## net.createConnection(path[, connectListener]) -### Event: 'end' +A factory function, which returns a new unix +['net.Socket'](#net_class_net_socket) and automatically connects to the +supplied `path`. -Emitted when the other end of the socket sends a FIN packet. +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -By default (`allowHalfOpen == false`) the socket will destroy its file -descriptor once it has written out its pending write queue. However, by -setting `allowHalfOpen == true` the socket will not automatically `end()` -its side allowing the user to write arbitrary amounts of data, with the -caveat that the user is required to `end()` their side now. +## net.createConnection(port[, host][, connectListener]) +A factory function, which returns a new +['net.Socket'](#net_class_net_socket) and automatically connects to the +supplied `port` and `host`. -### Event: 'timeout' +If `host` is omitted, `'localhost'` will be assumed. -Emitted if the socket times out from inactivity. This is only to notify that -the socket has been idle. The user must manually close the connection. +The `connectListener` parameter will be added as a listener for the +['connect'][] event once. -See also: `socket.setTimeout()` +## net.createServer([options][, connectionListener]) +Creates a new server. The `connectionListener` argument is +automatically set as a listener for the ['connection'][] event. -### Event: 'drain' +`options` is an object with the following defaults: -Emitted when the write buffer becomes empty. Can be used to throttle uploads. + { + allowHalfOpen: false, + pauseOnConnect: false + } -See also: the return values of `socket.write()` +If `allowHalfOpen` is `true`, then the socket won't automatically send a FIN +packet when the other end of the socket sends a FIN packet. The socket becomes +non-readable, but still writable. You should call the `end()` method explicitly. +See ['end'][] event for more information. -### Event: 'error' +If `pauseOnConnect` is `true`, then the socket associated with each incoming +connection will be paused, and no data will be read from its handle. This allows +connections to be passed between processes without any data being read by the +original process. To begin reading data from a paused socket, call `resume()`. -* {Error object} +Here is an example of an echo server which listens for connections +on port 8124: -Emitted when an error occurs. The `'close'` event will be called directly -following this event. + var net = require('net'); + var server = net.createServer(function(c) { //'connection' listener + console.log('client connected'); + c.on('end', function() { + console.log('client disconnected'); + }); + c.write('hello\r\n'); + c.pipe(c); + }); + server.listen(8124, function() { //'listening' listener + console.log('server bound'); + }); -### Event: 'close' +Test this by using `telnet`: -* `had_error` {Boolean} `true` if the socket had a transmission error. + telnet localhost 8124 -Emitted once the socket is fully closed. The argument `had_error` is a boolean -which says if the socket was closed due to a transmission error. +To listen on the socket `/tmp/echo.sock` the third line from the last would +just be changed to + + server.listen('/tmp/echo.sock', function() { //'listening' listener + +Use `nc` to connect to a UNIX domain socket server: + + nc -U /tmp/echo.sock ## net.isIP(input)