net¶

This module provides access to networking utilities.

Socket object¶

The Socket object is a thin object oriented wrapper around socket(2) and its related functionality.

class net.Socket(domain, type[, options])¶

Creates a socket object.

Arguments:

domain – Socket domain (one of net.AF_INET, net.AF_INET6 or net.AF_UNIX).
type – Socket type (one of net.SOCK_STREAM or net.SOCK_DGRAM).
options –
Optional object which may contain the following properties:
- fd: if specified, the socket is built with the given fd, an a new one is not created.
- nonBlocking: if specified and true, the socket will be breated in non-blocking mode.

See also

socket(2)

Note

Since version 0.3.0 the fds are created with O_CLOEXEC set. You can undo this using os.cloexec().

net.Socket.fd¶: Returns the file descriptor representing the socket.

net.Socket.prototype.accept()¶

Waits for an incoming connection and accepts it. Only works on listening sockets.

Returns:	The accepted `net.Socket()` object.

See also

accept(2)

net.Socket.prototype.bind(address)¶: Bind the socket to the given address. See Socket addresses for the format.

See also

bind(2)

net.Socket.prototype.close()¶: Closes the socket.

See also

close(2)

net.Socket.prototype.connect(address)¶: Starts a connection towards the given address. See Socket addresses for the format.

See also

connect(2)

net.Socket.prototype.getsockname()¶: Returns the socket’s local address. See Socket addresses for the format.

See also

getsockname(2)

net.Socket.prototype.getpeername()¶: Returns the socket’s peer address. See Socket addresses for the format.

See also

getpeername(2)

net.Socket.prototype.listen([backlog])¶

Set the socket in listening mode, ready for accepting connections.

Arguments:	backlog – The maximum length for the queue of pending connections. If not set it defaults to 128.

See also

listen(2)

net.Socket.prototype.recv([nrecv])¶

Receive data from a socket. It can only be used in a connected socket.

Arguments:	nrecv – Maximum amount of data to receive. If not specified it defaults to 4096. Alternatively, a Buffer can be passed, and data will be read into it.
Returns:	The data that was read as a Uint8Array or the amount of data read as a number, if a Buffer was passed.

See also

recv(2)

net.Socket.prototype.send(data)¶

Transmit a message to the other socket. It can only be used with connected sockets.

Arguments:	data – The message that will be transmitted (can be a string or a Buffer).
Returns:	The number of bytes from data which were actually sent.

See also

send(2)

net.Socket.prototype.recvfrom([nrecv])¶

Similar to net.Socket.prototype.recv() but it can also be used in non-connected sockets.

Returns:	An object with 2 properties: address, which contains the address of the sender and nread if a Buffer was used, or data, with the data as a Uint8Array.

See also

recvfrom(2)

net.Socket.prototype.sendto(data, address)¶: Similar to net.Socket.prototype.recv() but it can also be used in non-connected sockets and the destination address has to be specified.

See also

sendto(2)

net.Socket.prototype.shutdown(how)¶: Causes all or part of a full-duplex connection to be shut down. how must be one of net.SHUT_RD, net.SHUT_WR or net.SHUT_RDWR.

See also

shutdown(2)

net.Socket.prototype.setsockopt(level, option, value)¶

Set a socket option on the given level. value may contain either a number (for numeric or boolean options) or a string containing the binary representation of the value. Use of Buffer objects is recommended to build the binary value.

Example, setting a numeric or boolean option:

var sock = new net.Socket(net.AF_INET, net.SOCK_STREAM);
sock.setsockopt(net.SOL_SOCKET, net.SO_REUSEADDR, true);

Example, setting a binary option:

var sock = new net.Socket(net.AF_INET, net.SOCK_STREAM);
var lingerOpts = new Buffer(8);
lingerOpts.writeInt32LE(1, 0);    // enable lingering
lingerOpts.writeInt32LE(100, 4);    // linger for 100 seconds
sock.setsockopt(net.SOL_SOCKET, net.SO_LINGER, lingerOpts.toString());

See also

setsockopt(2)

net.Socket.prototype.getsockopt(level, option[, size])¶

Get the value for a socket option on the given level. When size is omitted, the value is assumed to be an integer, but when a number is given a buffer of size size is used. A Buffer object can be used to parse the result.

Example, getting a numeric or boolean option:

var sock = new net.Socket(net.AF_INET, net.SOCK_STREAM);
sock.setsockopt(net.SOL_SOCKET, net.SO_REUSEADDR, true);
var r = sock.getsockopt(net.SOL_SOCKET, net.SO_REUSEADDR);

Example, getting a binary option:

var sock = new net.Socket(net.AF_INET, net.SOCK_STREAM);
var lingerOpts = new Buffer(8);
lingerOpts.writeInt32LE(1, 0);    // enable lingering
lingerOpts.writeInt32LE(100, 4);    // linger for 100 seconds
sock.setsockopt(net.SOL_SOCKET, net.SO_LINGER, lingerOpts.toString());
var r = sock.sgetsockopt(net.SOL_SOCKET, net.SO_LINGER, 8);
var resBuf = new Buffer(r);
assert.equal(resBuf.readInt32LE(0), 1)
assert.equal(resBuf.readInt32LE(4), 100)

See also

getsockopt(2)

net.Socket.prototype.setNonBlocking(set)¶: Sets the socket in non-blocking mode if true, or blocking mode if false.

Constants¶

net.AF_INET¶: IPv4 socket domain.

net.AF_INET6¶: IPv6 socket domain.

net.AF_UNIX¶: Unix socket domain.

net.SOCK_STREAM¶: Stream socket type.

net.SOCK_DGRAM¶: Datagram socket type.

net.SHUT_RD¶

net.SHUT_WR¶

net.SHUT_RDWR¶: Shutdown modes for net.Socket.prototype.shutdown().

Functions¶

Socket addresses¶

Throughout this module, when an address is taken as a parameter or returned from a function, it’s expressed as an object with different properties, depending on the address family:

IPv4 sockets (AF_INET family): object containing host and port properties.
IPv6 sockets (AF_INET6 family): object containing host, port, flowinfo and scopeid properties. The last two can be omitted and will be assumed to be 0.
Unix sockets (AF_UNIX family): string containing the path.

getaddrinfo¶

net.getaddrinfo(hostname, servname[, hints])¶

Get a list of IP addresses and port numbers for host hostname and service servname. See getaddrinfo(3) for details.

Example:

sjs> var r = net.getaddrinfo('google.com', 'http');
sjs> outil.inspect(r);
= [ { family: 2,
    type: 2,
    protocol: 17,
    canonname: '',
    address: { host: '216.58.198.174', port: 80 } },
{ family: 2,
    type: 1,
    protocol: 6,
    canonname: '',
    address: { host: '216.58.198.174', port: 80 } },
{ family: 30,
    type: 2,
    protocol: 17,
    canonname: '',
    address:
    { host: '2a00:1450:4009:809::200e',
    port: 80,
    flowinfo: 0,
    scopeid: 0 } },
{ family: 30,
    type: 1,
    protocol: 6,
    canonname: '',
    address:
    { host: '2a00:1450:4009:809::200e',
    port: 80,
    flowinfo: 0,
    scopeid: 0 } } ]

The hints optional argument may contain an object with the following properties: family, type, protocol and flags.

Example:

sjs> var r = net.getaddrinfo('google.com', 'http', {family: net.AF_INET});
sjs> outil.inspect(r);
= [ { family: 2,
    type: 2,
    protocol: 17,
    canonname: '',
    address: { host: '216.58.198.174', port: 80 } },
{ family: 2,
    type: 1,
    protocol: 6,
    canonname: '',
    address: { host: '216.58.198.174', port: 80 } } ]

The returned result is a list of objects containing the following properties: family, type, protocol, canonname and address.

net.gai_strerror(code)¶: Get the string that describes the given error code.

net.gai_error_map¶: A Map mapping getaddrinfo error codes to their string versions.

net.AI_*¶: All addrinfo constants to be used as hints in net.getaddrinfo(). See getaddrinfo(3) for details.

net.EAI_*¶: All error codes net.getaddrinfo() could give. See getaddrinfo(3) for details.

net.SOL_*¶

net.IPPROTO_*¶: Levels to be used with net.Socket.prototype.setsockopt() and net.Socket.prototype.setsockopt().

net.SO_*¶

net.IP_*¶

net.IPV6_*¶

net.TCP_*¶: Options to be used with net.Socket.prototype.setsockopt() and net.Socket.prototype.setsockopt().

Utility functions¶

net.isIP(address)¶: Returns 4 if the given address is an IPv4 address, 6 if it’s an IPv6 address and 0 otherwise.

net.isIPv4(address)¶: Returns true if the given address is a valid IPv4 address, and false otherwise.

net.isIPv6(address)¶: Returns true if the given address is a valid IPv6 address, and false otherwise.

net¶

Socket object¶

Constants¶

Functions¶

Socket addresses¶

getaddrinfo¶

Utility functions¶

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