Class: net.BlockList#
Added in: v15.0.0, v14.18.0
The BlockList object can be used with some network APIs to specify rules for
disabling inbound or outbound access to specific IP addresses, IP ranges, or
IP subnets.
blockList.addAddress(address[, type])#
Added in: v15.0.0, v14.18.0
Adds a rule to block the given IP address.
blockList.addRange(start, end[, type])#
Added in: v15.0.0, v14.18.0
Adds a rule to block a range of IP addresses from start (inclusive) to
end (inclusive).
blockList.addSubnet(net, prefix[, type])#
Added in: v15.0.0, v14.18.0
net <string> | <net.SocketAddress> The network IPv4 or IPv6 address.
prefix <number> The number of CIDR prefix bits. For IPv4, this
must be a value between 0 and 32. For IPv6, this must be between
0 and 128.
type <string> Either 'ipv4' or 'ipv6'. Default: 'ipv4'.
Adds a rule to block a range of IP addresses specified as a subnet mask.
blockList.check(address[, type])#
Added in: v15.0.0, v14.18.0
Returns true if the given IP address matches any of the rules added to the
BlockList.
const blockList = new net.BlockList();
blockList.addAddress('123.123.123.123');
blockList.addRange('10.0.0.1', '10.0.0.10');
blockList.addSubnet('8592:757c:efae:4e45::', 64, 'ipv6');
console.log(blockList.check('123.123.123.123'));
console.log(blockList.check('10.0.0.3'));
console.log(blockList.check('222.111.111.222'));
console.log(blockList.check('::ffff:7b7b:7b7b', 'ipv6'));
console.log(blockList.check('::ffff:123.123.123.123', 'ipv6'));
blockList.rules#
Added in: v15.0.0, v14.18.0
The list of rules added to the blocklist.
BlockList.isBlockList(value)#
Added in: v22.13.0
value <any> Any JS value
- Returns
true if the value is a net.BlockList.
blockList.fromJSON(value)#
const blockList = new net.BlockList();
const data = [
'Subnet: IPv4 192.168.1.0/24',
'Address: IPv4 10.0.0.5',
'Range: IPv4 192.168.2.1-192.168.2.10',
'Range: IPv4 10.0.0.1-10.0.0.10',
];
blockList.fromJSON(data);
blockList.fromJSON(JSON.stringify(data));
Class: net.Server#
Added in: v0.1.90
This class is used to create a TCP or IPC server.
new net.Server([options][, connectionListener])#
net.Server is an EventEmitter with the following events:
Event: 'close'#
Added in: v0.5.0
Emitted when the server closes. If connections exist, this
event is not emitted until all connections are ended.
Event: 'connection'#
Added in: v0.1.90
Emitted when a new connection is made. socket is an instance of
net.Socket.
Event: 'error'#
Added in: v0.1.90
Emitted when an error occurs. Unlike net.Socket, the 'close'
event will not be emitted directly following this event unless
server.close() is manually called. See the example in discussion of
server.listen().
Event: 'listening'#
Added in: v0.1.90
Emitted when the server has been bound after calling server.listen().
Event: 'drop'#
Added in: v18.6.0, v16.17.0
When the number of connections reaches the threshold of server.maxConnections,
the server will drop new connections and emit 'drop' event instead. If it is a
TCP server, the argument is as follows, otherwise the argument is undefined.
data <Object> The argument passed to event listener.
server.address()#
Returns the bound address, the address family name, and port of the server
as reported by the operating system if listening on an IP socket
(useful to find which port was assigned when getting an OS-assigned address):
{ port: 12346, family: 'IPv4', address: '127.0.0.1' }.
For a server listening on a pipe or Unix domain socket, the name is returned
as a string.
const server = net.createServer((socket) => {
socket.end('goodbye\n');
}).on('error', (err) => {
throw err;
});
server.listen(() => {
console.log('opened server on', server.address());
});
server.address() returns null before the 'listening' event has been
emitted or after calling server.close().
server.close([callback])#
Added in: v0.1.90
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.
server[Symbol.asyncDispose]()#
Added in: v20.5.0, v18.18.0
Calls server.close() and returns a promise that fulfills when the
server has closed.
server.getConnections(callback)#
Added in: v0.9.7
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()#
Start a server listening for connections. A net.Server can be a TCP or
an IPC server depending on what it listens to.
Possible signatures:
This function is asynchronous. When the server starts listening, the
'listening' event will be emitted. The last parameter callback
will be added as a listener for the 'listening' event.
All listen() methods can take a backlog parameter to specify the maximum
length of the queue of pending connections. The actual length will be determined
by the OS through sysctl settings such as tcp_max_syn_backlog and somaxconn
on Linux. The default value of this parameter is 511 (not 512).
All net.Socket are set to SO_REUSEADDR (see socket(7) for
details).
The server.listen() method can be called again if and only if there was an
error during the first server.listen() call or server.close() has been
called. Otherwise, an ERR_SERVER_ALREADY_LISTEN error will be thrown.
One of the most common errors raised when listening is EADDRINUSE.
This happens when another server is already listening on the requested
port/path/handle. One way to handle this would be to retry
after a certain amount of time:
server.on('error', (e) => {
if (e.code === 'EADDRINUSE') {
console.error('Address in use, retrying...');
setTimeout(() => {
server.close();
server.listen(PORT, HOST);
}, 1000);
}
});
server.listen(handle[, backlog][, callback])#
Added in: v0.5.10
Start a server listening for connections on a given handle that has
already been bound to a port, a Unix domain socket, or a Windows named pipe.
The handle object can be either a server, a socket (anything with an
underlying _handle member), or an object with an fd member that is a
valid file descriptor.
Listening on a file descriptor is not supported on Windows.
server.listen(options[, callback])#
options <Object> Required. Supports the following properties:
backlog <number> Common parameter of server.listen()
functions.
exclusive <boolean> Default: false
host <string>
ipv6Only <boolean> For TCP servers, setting ipv6Only to true will
disable dual-stack support, i.e., binding to host :: won't make
0.0.0.0 be bound. Default: false.
reusePort <boolean> For TCP servers, setting reusePort to true allows
multiple sockets on the same host to bind to the same port. Incoming connections
are distributed by the operating system to listening sockets. This option is
available only on some platforms, such as Linux 3.9+, DragonFlyBSD 3.6+, FreeBSD 12.0+,
Solaris 11.4, and AIX 7.2.5+. Default: false.
path <string> Will be ignored if port is specified. See
Identifying paths for IPC connections.
port <number>
readableAll <boolean> For IPC servers makes the pipe readable
for all users. Default: false.
signal <AbortSignal> An AbortSignal that may be used to close a listening
server.
writableAll <boolean> For IPC servers makes the pipe writable
for all users. Default: false.
callback <Function>
functions.
- Returns: <net.Server>
If port is specified, it behaves the same as
server.listen([port[, host[, backlog]]][, callback]).
Otherwise, if path is specified, it behaves the same as
server.listen(path[, backlog][, callback]).
If none of them is specified, an error will be thrown.
If exclusive is false (default), then cluster workers will use the same
underlying handle, allowing connection handling duties to be shared. When
exclusive is true, the handle is not shared, and attempted port sharing
results in an error. An example which listens on an exclusive port is
shown below.
server.listen({
host: 'localhost',
port: 80,
exclusive: true,
});
When exclusive is true and the underlying handle is shared, it is
possible that several workers query a handle with different backlogs.
In this case, the first backlog passed to the master process will be used.
Starting an IPC server as root may cause the server path to be inaccessible for
unprivileged users. Using readableAll and writableAll will make the server
accessible for all users.
If the signal option is enabled, calling .abort() on the corresponding
AbortController is similar to calling .close() on the server:
const controller = new AbortController();
server.listen({
host: 'localhost',
port: 80,
signal: controller.signal,
});
controller.abort();
server.listen(path[, backlog][, callback])#
Added in: v0.1.90
Start an IPC server listening for connections on the given path.
server.listen([port[, host[, backlog]]][, callback])#
Added in: v0.1.90
Start a TCP server listening for connections on the given port and host.
If port is omitted or is 0, the operating system will assign an arbitrary
unused port, which can be retrieved by using server.address().port
after the 'listening' event has been emitted.
If host is omitted, the server will accept connections on the
unspecified IPv6 address (::) when IPv6 is available, or the
unspecified IPv4 address (0.0.0.0) otherwise.
In most operating systems, listening to the unspecified IPv6 address (::)
may cause the net.Server to also listen on the unspecified IPv4 address
(0.0.0.0).
server.listening#
Added in: v5.7.0
- Type: <boolean> Indicates whether or not the server is listening for connections.
server.maxConnections#
When the number of connections reaches the server.maxConnections threshold:
-
If the process is not running in cluster mode, Node.js will close the connection.
-
If the process is running in cluster mode, Node.js will, by default, route the connection to another worker process. To close the connection instead, set [server.dropMaxConnection][] to true.
It is not recommended to use this option once a socket has been sent to a child
with child_process.fork().
server.dropMaxConnection#
Added in: v22.12.0
Set this property to true to begin closing connections once the number of connections reaches the [server.maxConnections][] threshold. This setting is only effective in cluster mode.
server.ref()#
Added in: v0.9.1
Opposite of unref(), calling ref() on a previously unrefed server will
not let the program exit if it's the only server left (the default behavior).
If the server is refed calling ref() again will have no effect.
server.unref()#
Added in: v0.9.1
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 unrefed calling
unref() again will have no effect.
Class: net.Socket#
Added in: v0.3.4
This class is an abstraction of a TCP socket or a streaming IPC endpoint
(uses named pipes on Windows, and Unix domain sockets otherwise). It is also
an EventEmitter.
A net.Socket can be created by the user and used directly to interact with
a server. For example, it is returned by net.createConnection(),
so the user can use it to talk to the server.
It can also be created by Node.js and passed to the user when a connection
is received. For example, it is passed to the listeners of a
'connection' event emitted on a net.Server, so the user can use
it to interact with the client.
new net.Socket([options])#
options <Object> Available options are:
allowHalfOpen <boolean> If set to false, then the socket will
automatically end the writable side when the readable side ends. See
net.createServer() and the 'end' event for details. Default:
false.
fd <number> If specified, wrap around an existing socket with
the given file descriptor, otherwise a new socket will be created.
onread <Object> If specified, incoming data is stored in a single buffer
and passed to the supplied callback when data arrives on the socket.
This will cause the streaming functionality to not provide any data.
The socket will emit events like 'error', 'end', and 'close'
as usual. Methods like pause() and resume() will also behave as
expected.
buffer <Buffer> | <Uint8Array> | <Function> Either a reusable chunk of memory to
use for storing incoming data or a function that returns such.
callback <Function> This function is called for every chunk of incoming
data. Two arguments are passed to it: the number of bytes written to
buffer and a reference to buffer. Return false from this function to
implicitly pause() the socket. This function will be executed in the
global context.
readable <boolean> Allow reads on the socket when an fd is passed,
otherwise ignored. Default: false.
signal <AbortSignal> An Abort signal that may be used to destroy the
socket.
writable <boolean> Allow writes on the socket when an fd is passed,
otherwise ignored. Default: false.
- Returns: <net.Socket>
Creates a new socket object.
The newly created socket can be either a TCP socket or a streaming IPC
endpoint, depending on what it connect() to.
Event: 'close'#
Added in: v0.1.90
hadError <boolean> true if the socket had a transmission error.
Emitted once the socket is fully closed. The argument hadError is a boolean
which says if the socket was closed due to a transmission error.
Event: 'connect'#
Added in: v0.1.90
Emitted when a socket connection is successfully established.
See net.createConnection().
Event: 'connectionAttempt'#
Added in: v21.6.0, v20.12.0
ip <string> The IP which the socket is attempting to connect to.
port <number> The port which the socket is attempting to connect to.
family <number> The family of the IP. It can be 6 for IPv6 or 4 for IPv4.
Emitted when a new connection attempt is started. This may be emitted multiple times
if the family autoselection algorithm is enabled in socket.connect(options).
Event: 'connectionAttemptFailed'#
Added in: v21.6.0, v20.12.0
ip <string> The IP which the socket attempted to connect to.
port <number> The port which the socket attempted to connect to.
family <number> The family of the IP. It can be 6 for IPv6 or 4 for IPv4.
error <Error> The error associated with the failure.
Emitted when a connection attempt failed. This may be emitted multiple times
if the family autoselection algorithm is enabled in socket.connect(options).
Event: 'connectionAttemptTimeout'#
Added in: v21.6.0, v20.12.0
ip <string> The IP which the socket attempted to connect to.
port <number> The port which the socket attempted to connect to.
family <number> The family of the IP. It can be 6 for IPv6 or 4 for IPv4.
Emitted when a connection attempt timed out. This is only emitted (and may be
emitted multiple times) if the family autoselection algorithm is enabled
in socket.connect(options).
Event: 'data'#
Added in: v0.1.90
Emitted when data is received. The argument data will be a Buffer or
String. Encoding of data is set by socket.setEncoding().
The data will be lost if there is no listener when a Socket
emits a 'data' event.
Event: 'drain'#
Added in: v0.1.90
Emitted when the write buffer becomes empty. Can be used to throttle uploads.
See also: the return values of socket.write().
Event: 'end'#
Added in: v0.1.90
Emitted when the other end of the socket signals the end of transmission, thus
ending the readable side of the socket.
By default (allowHalfOpen is false) the socket will send an end of
transmission packet back and destroy its file descriptor once it has written out
its pending write queue. However, if allowHalfOpen is set to true, the
socket will not automatically end() its writable side,
allowing the user to write arbitrary amounts of data. The user must call
end() explicitly to close the connection (i.e. sending a
FIN packet back).
Event: 'error'#
Added in: v0.1.90
Emitted when an error occurs. The 'close' event will be called directly
following this event.
Event: 'lookup'#
Emitted after resolving the host name but before connecting.
Not applicable to Unix sockets.
Event: 'ready'#
Added in: v9.11.0
Emitted when a socket is ready to be used.
Triggered immediately after 'connect'.
Event: 'timeout'#
Added in: v0.1.90
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:
{ port: 12346, family: 'IPv4', address: '127.0.0.1' }
socket.autoSelectFamilyAttemptedAddresses#
Added in: v19.4.0, v18.18.0
This property is only present if the family autoselection algorithm is enabled in
socket.connect(options) and it is an array of the addresses that have been attempted.
Each address is a string in the form of $IP:$PORT. If the connection was successful,
then the last address is the one that the socket is currently connected to.
socket.bufferSize#
Added in: v0.3.8Deprecated since: v14.6.0
This property shows the number of characters buffered for writing. The buffer
may contain strings whose length after encoding is not yet known. So this number
is only an approximation of the number of bytes in the buffer.
net.Socket has the property that socket.write() always works. This is to
help users get up and running quickly. The computer cannot always keep up
with the amount of data that is written to a socket. The network connection
simply might be too slow. Node.js will internally queue up the data written to a
socket and send it out over the wire when it is possible.
The consequence of this internal buffering is that memory may grow.
Users who experience large or growing bufferSize should attempt to
"throttle" the data flows in their program with
socket.pause() and socket.resume().
socket.bytesRead#
Added in: v0.5.3
The amount of received bytes.
socket.bytesWritten#
Added in: v0.5.3
The amount of bytes sent.
socket.connect()#
Initiate a connection on a given socket.
Possible signatures:
This function is asynchronous. When the connection is established, the
'connect' event will be emitted. If there is a problem connecting,
instead of a 'connect' event, an 'error' event will be emitted with
the error passed to the 'error' listener.
The last parameter connectListener, if supplied, will be added as a listener
for the 'connect' event once.
This function should only be used for reconnecting a socket after
'close' has been emitted or otherwise it may lead to undefined
behavior.
socket.connect(options[, connectListener])#
Initiate a connection on a given socket. Normally this method is not needed,
the socket should be created and opened with net.createConnection(). Use
this only when implementing a custom Socket.
For TCP connections, available options are:
autoSelectFamily <boolean>: If set to true, it enables a family
autodetection algorithm that loosely implements section 5 of RFC 8305. The
all option passed to lookup is set to true and the sockets attempts to
connect to all obtained IPv6 and IPv4 addresses, in sequence, until a
connection is established. The first returned AAAA address is tried first,
then the first returned A address, then the second returned AAAA address and
so on. Each connection attempt (but the last one) is given the amount of time
specified by the autoSelectFamilyAttemptTimeout option before timing out and
trying the next address. Ignored if the family option is not 0 or if
localAddress is set. Connection errors are not emitted if at least one
connection succeeds. If all connections attempts fails, a single
AggregateError with all failed attempts is emitted. Default:
net.getDefaultAutoSelectFamily().
autoSelectFamilyAttemptTimeout <number>: The amount of time in milliseconds
to wait for a connection attempt to finish before trying the next address when
using the autoSelectFamily option. If set to a positive integer less than
10, then the value 10 will be used instead. Default:
net.getDefaultAutoSelectFamilyAttemptTimeout().
family <number>: Version of IP stack. Must be 4, 6, or 0. The value
0 indicates that both IPv4 and IPv6 addresses are allowed. Default: 0.
hints <number> Optional dns.lookup() hints.
host <string> Host the socket should connect to. Default: 'localhost'.
keepAlive <boolean> If set to true, it enables keep-alive functionality on
the socket immediately after the connection is established, similarly on what
is done in socket.setKeepAlive(). Default: false.
keepAliveInitialDelay <number> If set to a positive number, it sets the
initial delay before the first keepalive probe is sent on an idle socket.
Default: 0.
localAddress <string> Local address the socket should connect from.
localPort <number> Local port the socket should connect from.
lookup <Function> Custom lookup function. Default: dns.lookup().
noDelay <boolean> If set to true, it disables the use of Nagle's algorithm
immediately after the socket is established. Default: false.
port <number> Required. Port the socket should connect to.
blockList <net.BlockList> blockList can be used for disabling outbound
access to specific IP addresses, IP ranges, or IP subnets.
For IPC connections, available options are:
socket.destroy([error])#
Added in: v0.1.90
Ensures that no more I/O activity happens on this socket.
Destroys the stream and closes the connection.
See writable.destroy() for further details.
socket.destroyed#
- Type: <boolean> Indicates if the connection is destroyed or not. Once a
connection is destroyed no further data can be transferred using it.
See writable.destroyed for further details.
socket.destroySoon()#
Added in: v0.3.4
Destroys the socket after all data is written. If the 'finish' event was
already emitted the socket is destroyed immediately. If the socket is still
writable it implicitly calls socket.end().
socket.end([data[, encoding]][, callback])#
Added in: v0.1.90
Half-closes the socket. i.e., it sends a FIN packet. It is possible the
server will still send some data.
See writable.end() for further details.
socket.localAddress#
Added in: v0.9.6
The string representation of the local IP address the remote client is
connecting on. For example, in a server listening on '0.0.0.0', if a client
connects on '192.168.1.1', the value of socket.localAddress would be
'192.168.1.1'.
socket.localPort#
Added in: v0.9.6
The numeric representation of the local port. For example, 80 or 21.
socket.localFamily#
Added in: v18.8.0, v16.18.0
The string representation of the local IP family. 'IPv4' or 'IPv6'.
socket.pause()#
Pauses the reading of data. That is, 'data' events will not be emitted.
Useful to throttle back an upload.
socket.pending#
Added in: v11.2.0, v10.16.0
This is true if the socket is not connected yet, either because .connect()
has not yet been called or because it is still in the process of connecting
(see socket.connecting).
socket.ref()#
Added in: v0.9.1
Opposite of unref(), calling ref() on a previously unrefed socket will
not let the program exit if it's the only socket left (the default behavior).
If the socket is refed calling ref again will have no effect.
socket.remoteAddress#
Added in: v0.5.10
The string representation of the remote IP address. For example,
'74.125.127.100' or '2001:4860:a005::68'. Value may be undefined if
the socket is destroyed (for example, if the client disconnected).
socket.remoteFamily#
Added in: v0.11.14
The string representation of the remote IP family. 'IPv4' or 'IPv6'. Value may be undefined if
the socket is destroyed (for example, if the client disconnected).
socket.remotePort#
Added in: v0.5.10
The numeric representation of the remote port. For example, 80 or 21. Value may be undefined if
the socket is destroyed (for example, if the client disconnected).
socket.resetAndDestroy()#
Added in: v18.3.0, v16.17.0
Close the TCP connection by sending an RST packet and destroy the stream.
If this TCP socket is in connecting status, it will send an RST packet and destroy this TCP socket once it is connected.
Otherwise, it will call socket.destroy with an ERR_SOCKET_CLOSED Error.
If this is not a TCP socket (for example, a pipe), calling this method will immediately throw an ERR_INVALID_HANDLE_TYPE Error.
socket.setKeepAlive([enable][, initialDelay])#
Enable/disable keep-alive functionality, and optionally set the initial
delay before the first keepalive probe is sent on an idle socket.
Set initialDelay (in milliseconds) to set the delay between the last
data packet received and the first keepalive probe. Setting 0 for
initialDelay will leave the value unchanged from the default
(or previous) setting.
Enabling the keep-alive functionality will set the following socket options:
SO_KEEPALIVE=1
TCP_KEEPIDLE=initialDelay
TCP_KEEPCNT=10
TCP_KEEPINTVL=1
socket.setNoDelay([noDelay])#
Added in: v0.1.90
Enable/disable the use of Nagle's algorithm.
When a TCP connection is created, it will have Nagle's algorithm enabled.
Nagle's algorithm delays data before it is sent via the network. It attempts
to optimize throughput at the expense of latency.
Passing true for noDelay or not passing an argument will disable Nagle's
algorithm for the socket. Passing false for noDelay will enable Nagle's
algorithm.
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 call
socket.end() or socket.destroy() to end the connection.
socket.setTimeout(3000);
socket.on('timeout', () => {
console.log('socket timeout');
socket.end();
});
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.
socket.timeout#
Added in: v10.7.0
The socket timeout in milliseconds as set by socket.setTimeout().
It is undefined if a timeout has not been set.
socket.unref()#
Added in: v0.9.1
Calling unref() on a socket will allow the program to exit if this is the only
active socket in the event system. If the socket is already unrefed calling
unref() again will have no effect.
socket.write(data[, encoding][, callback])#
Added in: v0.1.90
Sends data on the socket. The second parameter specifies the encoding in the
case of a string. It defaults to UTF8 encoding.
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.
The optional callback parameter will be executed when the data is finally
written out, which may not be immediately.
See Writable stream write() method for more
information.
socket.readyState#
Added in: v0.5.0
This property represents the state of the connection as a string.
- If the stream is connecting
socket.readyState is opening.
- If the stream is readable and writable, it is
open.
- If the stream is readable and not writable, it is
readOnly.
- If the stream is not readable and writable, it is
writeOnly.
net.createConnection()#
A factory function, which creates a new net.Socket,
immediately initiates connection with socket.connect(),
then returns the net.Socket that starts the connection.
When the connection is established, a 'connect' event will be emitted
on the returned socket. The last parameter connectListener, if supplied,
will be added as a listener for the 'connect' event once.
Possible signatures:
The net.connect() function is an alias to this function.
net.createConnection(options[, connectListener])#
Added in: v0.1.90
For available options, see
new net.Socket([options])
and socket.connect(options[, connectListener]).
Additional options:
Following is an example of a client of the echo server described
in the net.createServer() section:
import net from 'node:net';
const client = net.createConnection({ port: 8124 }, () => {
console.log('connected to server!');
client.write('world!\r\n');
});
client.on('data', (data) => {
console.log(data.toString());
client.end();
});
client.on('end', () => {
console.log('disconnected from server');
});const net = require('node:net');
const client = net.createConnection({ port: 8124 }, () => {
console.log('connected to server!');
client.write('world!\r\n');
});
client.on('data', (data) => {
console.log(data.toString());
client.end();
});
client.on('end', () => {
console.log('disconnected from server');
});
To connect on the socket /tmp/echo.sock:
const client = net.createConnection({ path: '/tmp/echo.sock' });
Following is an example of a client using the port and onread
option. In this case, the onread option will be only used to call
new net.Socket([options]) and the port option will be used to
call socket.connect(options[, connectListener]).
import net from 'node:net';
import { Buffer } from 'node:buffer';
net.createConnection({
port: 8124,
onread: {
buffer: Buffer.alloc(4 * 1024),
callback: function(nread, buf) {
console.log(buf.toString('utf8', 0, nread));
},
},
});const net = require('node:net');
net.createConnection({
port: 8124,
onread: {
buffer: Buffer.alloc(4 * 1024),
callback: function(nread, buf) {
console.log(buf.toString('utf8', 0, nread));
},
},
});
net.createConnection(path[, connectListener])#
Added in: v0.1.90
Initiates an IPC connection.
This function creates a new net.Socket with all options set to default,
immediately initiates connection with
socket.connect(path[, connectListener]),
then returns the net.Socket that starts the connection.
net.createConnection(port[, host][, connectListener])#
Added in: v0.1.90
Initiates a TCP connection.
This function creates a new net.Socket with all options set to default,
immediately initiates connection with
socket.connect(port[, host][, connectListener]),
then returns the net.Socket that starts the connection.
net.createServer([options][, connectionListener])#
Creates a new TCP or IPC server.
If allowHalfOpen is set to true, when the other end of the socket
signals the end of transmission, the server will only send back the end of
transmission when socket.end() is explicitly called. For example, in the
context of TCP, when a FIN packed is received, a FIN packed is sent
back only when socket.end() is explicitly called. Until then the
connection is half-closed (non-readable but still writable). See 'end'
event and RFC 1122 (section 4.2.2.13) for more information.
If pauseOnConnect is set to 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
socket.resume().
The server can be a TCP server or an IPC server, depending on what it
listen() to.
Here is an example of a TCP echo server which listens for connections
on port 8124:
import net from 'node:net';
const server = net.createServer((c) => {
console.log('client connected');
c.on('end', () => {
console.log('client disconnected');
});
c.write('hello\r\n');
c.pipe(c);
});
server.on('error', (err) => {
throw err;
});
server.listen(8124, () => {
console.log('server bound');
});const net = require('node:net');
const server = net.createServer((c) => {
console.log('client connected');
c.on('end', () => {
console.log('client disconnected');
});
c.write('hello\r\n');
c.pipe(c);
});
server.on('error', (err) => {
throw err;
});
server.listen(8124, () => {
console.log('server bound');
});
Test this by using telnet:
telnet localhost 8124
To listen on the socket /tmp/echo.sock:
server.listen('/tmp/echo.sock', () => {
console.log('server bound');
});
Use nc to connect to a Unix domain socket server:
nc -U /tmp/echo.sock