NAME
Socket::Class - A class to communicate with sockets
SYNOPSIS
use Socket::Class;DESCRIPTION
Socket::Class provides a simple, fast and efficient way to communicate with sockets. It operates outside of the PerlIO layer and can be used as a replacement of IO::Socket. Little parts of Bluetooth technology has been integrated. Please see below.
Bluetooth
The standard build includes Bluetooth protocols for RFCOMM (stream) and L2CAP (datagram). Bluetooth adapters on a MS-Windows operation system must be compatible with the Windows Bluetooth API to get it working. More specific Bluetooth support could be added in the future.
Functions by Category
Main Functions
Sending and Receiving
Address Functions
get_hostname, local_addr, local_path, local_port, pack_addr, remote_addr, remote_path, remote_port, unpack_addr
Socket Options
get_blocking, get_broadcast, get_option, get_rcvbuf_size, get_reuseaddr, get_sndbuf_size, get_timeout, get_tcp_nodelay, set_blocking, set_broadcast, set_option, set_rcvbuf_size, set_reuseaddr, set_sndbuf_size, set_timeout, set_tcp_nodelay
Miscellaneous Functions
Error Handling
EXAMPLES
Simple Internet Server
use Socket::Class qw($SO_MAXCONN);
# create a new socket at port 9999 and listen for clients
$server = Socket::Class->new(
'local_port' => 9999,
'listen' => $SO_MAXCONN,
) or die Socket::Class->error;
# wait for clients
while( $client = $server->accept() ) {
# somebody connected to us (we are local, client's address is remote)
print 'Incoming connection from '
. $client->remote_addr . ' port ' . $client->remote_port . "\n";
# do something with the client
$client->say( 'hello client' );
...
$client->wait( 100 );
# close the client connection and free its resources
$client->free();
}Simple Internet Client
use Socket::Class;
# create a new socket and connect to the server at localhost on port 9999
$client = Socket::Class->new(
'remote_addr' => 'localhost',
'remote_port' => 9999,
) or die Socket::Class->error;
# do something with the socket
$str = $client->readline();
print $str, "\n";
# close the client connection and free its resources
$client->free();Simple HTTP Client
use Socket::Class;
# create a new socket and connect to www.perl.org
$sock = Socket::Class->new(
'remote_addr' => 'www.perl.org',
'remote_port' => 'http',
) or die Socket::Class->error;
# request the main site
$sock->write(
"GET / HTTP/1.0\r\n" .
"User-Agent: Not Mozilla\r\n" .
"Host: " . $sock->remote_addr . "\r\n" .
"Connection: Close\r\n" .
"\r\n"
) or die $sock->error;
# read the response (1MB max)
$sock->read( $buf, 1048576 )
or die $sock->error;
# do something with the response
print $buf;
# close the socket an free its resources
$sock->free();Bluetooth RFCOMM Client
use Socket::Class;
# create a new socket and connect to a bluetooth device
$sock = Socket::Class->new(
'domain' => 'bluetooth',
'type' => 'stream',
'proto' => 'rfcomm',
'remote_addr' => '00:16:20:66:F2:6C',
'remote_port' => 1, # channel
) or die Socket::Class->error;
# do something with the socket
$sock->send( "bluetooth works" );
...
# close the connection and free its resources
$sock->free();METHODS
Constructing
- new ( [%arg] )
-
Creates a Socket::Class object, which is a reference to a newly created socket handle. new() optionally takes arguments, these arguments are in key-value pairs.
remote_addr Remote host address <hostname> | <hostaddr> remote_port Remote port or service <service> | <number> remote_path Remote path for unix sockets "/tmp/mysql.sock" local_addr Local host bind address <hostname> | <hostaddr> local_port Local host bind port <service> | <number> local_path Local path for unix sockets "/tmp/myserver.sock" domain Socket domain name (or number) "inet" | "inet6" | ... proto Protocol name (or number) "tcp" | "udp" | ... type Socket type name (or number) "stream" | "dgram" | ... listen Put socket into listen state with a specified maximal number of connections in the queue broadcast Set SO_BROADCAST before binding reuseaddr Set SO_REUSEADDR before binding blocking Enable or disable blocking mode; default is enabled timeout Timeout value for various operations as floating point number; defaults to 15000 (15 seconds); currently used for connectIf local_addr, local_port or local_path is defined then the socket will bind a local address. If listen is defined then the socket will put into listen state. If remote_addr, remote_port or remote_path is defined then connect() is called.
Standard domain is AF_INET. Standard type is SOCK_STREAM. Standard proto is IPPROTO_TCP. If local_path or remote_path is defined the standard domain changes to AF_UNIX and the standard protocol changes to 0.
Examples
Create a nonblocking listening inet socket on a random local port
$sock = Socket::Class->new( 'listen' => 5, 'blocking' => 0, ) or die Socket::Class->error; print "listen on local port ", $sock->local_port, "\n";Create a listening unix socket
$sock = Socket::Class->new( 'domain' => 'unix', 'local_path' => '/tmp/myserver.sock', 'listen' => 5, ) or die Socket::Class->error;Connect to smtp service (port 25) on localhost
$sock = Socket::Class->new( 'remote_addr' => 'localhost', 'remote_addr' => 'smtp', ) or die Socket::Class->error;Create a broadcast socket
$sock = Socket::Class->new( 'remote_addr' => "255.255.255.255", 'remote_port' => 9999, 'proto' => 'udp', 'local_addr' => 'localhost', 'broadcast' => 1, ) or die Socket::Class->error;
Closing / Destructing / Freeing
An undef on the reference variable will free the socket and its resources. A call of free() will free the socket resource explicitely.
- shutdown ( [$how] )
-
Disables sends and receives on the socket.
Parameters
$how
One of the following values that specifies the operation that will no longer be allowed. Default is $SD_SEND.
Num Const Description ---------------------------------------------------------------------- 0 $SD_SEND Disable sending on the socket. 1 $SD_RECEIVE Disable receiving on the socket. 2 $SD_BOTH Disable both sending and receiving on the socket.Return Values
Returns TRUE on succes or FALSE on failure. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
use Socket::Class qw($SD_BOTH); $sock = Socket::Class->new( ... ); ... $sock->shutdown( $SD_BOTH ); $sock->free(); - close ()
-
Closes the socket without freeing internal resources.
- free ()
-
Closes the socket and frees all internally allocated resources.
Bind and Accept
- bind ( [$addr [, $port]] )
- bind ( [$path] )
-
Binds the socket to a specified local address.
Parameters
$addr or $path
On 'inet' family sockets the $addr parameter can be an IP address in dotted-quad notation (e.g. 127.0.0.1) or a valid hostname.
On 'inet6' family sockets the $addr parameter can be an IPv6 address in hexadecimal notation (e.g. 2001:0db8:85a3:08d3:1319:8a2e:0370:7344) or a valid hostname.
On 'unix' family sockets the $path is the pathname of a Unix domain socket.
If $addr is not defined the address from last bind is used.
$port
The $port parameter designates the port or channel on the local host.
Return Values
Returns TRUE on succes or FALSE on failure. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$sock->bind( '0.0.0.0', 9999 ) or die "can't bind: " . $sock->error; - accept ()
-
Accepts a connection on a bound socket. Once a successful connection is made, a new socket resource is returned, which may be used for communication. If there are multiple connections queued on the socket, the first will be used. If there are no pending connections, accept() will block until a connection becomes present. If socket has been made non-blocking using set_blocking(), 0 will be returned.
Return Values
Returns a new socket class on succes or 0 on non-blocking mode and no new connection becomes available or UNDEF on failure. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
Blocking mode (default)
while( $client = $sock->accept() ) { # do something with the connection print "Incoming connection: ", $client->to_string, "\n"; ... $client->free(); }Non blocking mode
while( 1 ) { $client = $sock->accept(); if( ! defined $client ) { # error die $sock->error; } elsif( ! $client ) { # no client, sleep for a while $sock->wait( 10 ); next; } # do something with the connection print "Incoming connection: ", $client->to_string, "\n"; ... $client->free(); }
Connect
- connect ( [$addr [, $port [, $timeout]]] )
- connect ( [$path [,$timeout]] )
-
Initiates a connection.
Parameters
$addr or $path
On 'inet' family sockets the $addr parameter can be an IP address in dotted-quad notation (e.g. 127.0.0.1) or a valid hostname.
On 'inet6' family sockets the $addr parameter can be an IPv6 address in hexadecimal notation (e.g. 2001:0db8:85a3:08d3:1319:8a2e:0370:7344) or a valid hostname.
On 'unix' family sockets the $path is the pathname of a Unix domain socket.
If $addr is not defined the address from last connect is used.
$port
The $port parameter designates the port or service on the remote host to which a connection should be made.
$timeout
Optionally timeout in milliseconds as floating point number.
Return Values
Returns a TRUE value on succes or UNDEF on failure. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$sock->connect( 'www.perl.org', 'http' ) or die "can't connect: " . $sock->error; - reconnect ( [$timeout] )
-
Closes the current connection, waits $timeout milliseconds and reconnects the socket to the connection previously made.
Return Values
Returns a TRUE value on succes or UNDEF on failure. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
if( $sock->is_error ) { retry: print "socket error: ", $sock->error, "\n"; # try to reconnect $r = $sock->reconnect( 1000 ); if( ! $r ) { # can't connect goto retry; } }
Low level sending and receiving data
- send ( $buf [, $flags] )
-
Sends data to a connected socket.
Parameters
$buf
A buffer containing the data that will be sent to the remote host.
$flags
The value of $flags can be any combination of the following:
Number Constant Description ------------------------------------------------------------- 0x1 $MSG_OOB Process OOB (out-of-band) data 0x2 $MSG_PEEK Peek at incoming message 0x4 $MSG_DONTROUTE Bypass routing, use direct interface 0x8 $MSG_CTRUNC Data completes record 0x100 $MSG_WAITALL Data completes transactionReturn Values
Returns the number of bytes sent or UNDEF if an error occured. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$r = $sock->send( "important message" ); if( ! defined $r ) { # error die "can't sent: " . $sock->error; } print "sent $r bytes\n";See Also
- recv ( $buf, $len [, $flags] )
-
Receives data from a connected socket.
Parameters
$buf
A variable to write the received bytes into.
$len
The number of bytes to receive.
$flags
The value of $flags can be any combination of the following:
Number Constant Description --------------------------------------------------------------------------- 0x1 $MSG_OOB Process OOB (out-of-band) data 0x2 $MSG_PEEK Peek at incoming message 0x4 $MSG_DONTROUTE Bypass routing, use direct interface 0x8 $MSG_CTRUNC Data completes record 0x20 $MSG_TRUNC Return the real length of the packet, even when it was longer than the passed buffer. Only valid for packet sockets.Return Values
Returns the number of bytes received or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
See Also
- sendto ( $buf [, $to [, $flags]] )
-
Sends a message to a socket, whether it is connected or not.
Parameters
$buf
A buffer containing the data that will be sent to the remote host.
$to
Packed address of the remote host. (See pack_addr function)
$flags
The value of $flags can be any combination of the following:
Number Constant Description ------------------------------------------------------------- 0x1 $MSG_OOB Process OOB (out-of-band) data 0x2 $MSG_PEEK Peek at incoming message 0x4 $MSG_DONTROUTE Bypass routing, use direct interfaceReturn Values
Returns the bytes sent to the remote host or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$sock = Socket::Class->new( 'proto' => 'udp' ); $paddr = $sock->pack_addr( 'localhost', 9999 ); $sock->sendto( 'PING', $paddr );OR
$sock = Socket::Class->new( 'proto' => 'udp', 'remote_addr' => 'localhost', 'remote_port' => 9999, ); $sock->sento( 'PING' );See Also
- recvfrom ( $buf, $len [, $flags] )
-
Receives data from a socket whether or not it is connection-oriented
Parameters
$buf
The data received will be fetched to the variable specified with buf.
$len
Up to len bytes will be fetched from remote host.
$flags
The following table contains the different flags that can be set using the $flags parameter. Use the OR logic operator (|) to use more than one flag.
Number Constant Description --------------------------------------------------------------------------- 0x1 $MSG_OOB Process OOB (out-of-band) data 0x2 $MSG_PEEK Receive data from the beginning of the receive queue without removing it from the queue. 0x40 $MSG_DONTWAIT With this flag set, the function returns even if it would normally have blocked. 0x100 $MSG_WAITALL Block until at least len are received. However, if a signal is caught or the remote host disconnects, the function may return less data.Return Values
Returns a packed address of the sender or 0 on non-blocking mode and no data becomes available or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
Blocking mode (default)
while( $paddr = $sock->recvfrom( $buf, 1024 ) ) { ( $r_addr, $r_port ) = $sock->unpack_addr( $paddr ); print "Incoming message from $r_addr port $r_port\n"; }Non blocking mode
while( 1 ) { $paddr = $sock->recvfrom( $buf, 1024 ); if( ! defined $paddr ) { # error die $sock->error; } elsif( ! $paddr ) { # no data, sleep for a while $sock->wait( 10 ); next; } ( $r_addr, $r_port ) = $sock->unpack_addr( $paddr ); print "Incoming message from $r_addr port $r_port\n"; }See Also
Higher level sending and receiving
- write ( $buffer [, $length] )
-
Writes to the socket from the given buffer.
Parameters
$buffer
The buffer to be written.
$length
The optional parameter $length can specify an alternate length of bytes written to the socket. If this length is greater then the buffer length, it is silently truncated to the length of the buffer.
Return Values
Returns the number of bytes successfully written to the socket or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Notes
Note: write () does not necessarily write all bytes from the given buffer. It's valid that, depending on the network buffers etc., only a certain amount of data, even one byte, is written though your buffer is greater. You have to watch out so you don't unintentionally forget to transmit the rest of your data.
- read ( $buffer, $length )
-
Reads a maximum of length bytes from a socket.
Parameters
$buffer
A variable to write the read bytes into.
$length
The maximum number of bytes read is specified by the length parameter.
Return Values
Returns number of bytes read or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- print ( ... )
-
Writes to the socket from the given parameters. print maps to write
Return Values
Returns the number of bytes successfully written to the socket or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$sock->print( 'hello client', "\n" ); - printf ( $fmt, ... )
-
Writes formated string to the socket.
Parameters
$fmt
Defines the format of the string. See Perl printf and sprintf for more details
Return Values
Returns the number of bytes successfully written to the socket or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
# round number to 3 digits after decimal point and send it $sock->printf( "%.3f", $number ); # does the same like above $sock->write( sprintf( "%.3f", $number ) ); - say ( ... )
- writeline ( ... )
-
Writes to the socket from the given string plus a newline char (\n). writeline is a synonym for say.
Return Values
Returns the number of bytes successfully written to the socket or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$sock->say( 'hello client' ); - readline ()
-
Reads characters from the socket and stops at \n or \r\n.
Return Values
Returns a string value or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Socket options
- set_blocking ( [$int] )
-
Sets blocking mode on the socket.
Parameters
$int
On 1 set blocking mode, on 0 set non-blocking mode.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_blocking ()
-
Returns the current blocking state.
Return Values
Return a TRUE value on blocking mode, or FALSE on non-blocking mode, or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_reuseaddr ( [$int] )
-
Sets the SO_REUSEADDR socket option.
Parameters
$int
On 1 enable reusaddr, on 0 disable reusaddr.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_reuseaddr ()
-
Returns the current value of SO_REUSEADDR.
Return Values
Return the value of SO_REUSEADDR or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_broadcast ( [$int] )
-
Sets the SO_BROADCAST socket option.
Parameters
$int
On 1 enable reusaddr, on 0 disable reusaddr.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_broadcast ()
-
Returns the current value of SO_BROADCAST.
Return Values
Return the value of SO_BROADCAST or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_rcvbuf_size ( [$size] )
-
Sets the SO_RCVBUF socket option.
Parameters
$size
The size of the receive buffer.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_rcvbuf_size ()
-
Returns the current value of SO_RCVBUF.
Return Values
Return the value of SO_RCVBUF or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_sndbuf_size ( [$size] )
-
Sets the SO_SNDBUF socket option.
Parameters
$size
The size of the send buffer.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_sndbuf_size ()
-
Returns the current value of SO_SNDBUF.
Return Values
Return the value of SO_SNDBUF or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_timeout ( [$ms] )
-
Sets the timeout for various operations.
Parameters
$ms
The timeout in milliseconds as floating point number.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_timeout ()
-
Returns the current timeout.
Return Values
Return the timeout in milliseconds or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_tcp_nodelay ( [$int] )
-
Sets the TCP_NODELAY socket option.
Parameters
$int
On 1 disable the naggle algorithm, on 0 enable it.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- get_tcp_nodelay ()
-
Returns the current value of TCP_NODELAY.
Return Values
Return the value of TCP_NODELAY or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- set_option ( $level, $optname, $optval, ... )
-
Sets socket options for the socket.
Parameters
$level
The level parameter specifies the protocol level at which the option resides. For example, to retrieve options at the socket level, a level parameter of SOL_SOCKET would be used. Other levels, such as TCP, can be used by specifying the protocol number of that level.
$optname
A valid socket option.
$optval ...
The option value in packed or unpacked format. If $optval is an integer value it will be packed as int. For SO_LINGER, SO_RCVTIMEO and SO_SNDTIMEO one or two values are accepted and are packed in the right format.
Return Values
Return a TRUE value on succes or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
use Socket::Class qw($SOL_SOCKET $SO_LINGER $SO_RCVTIMEO); $sock = Socket::Class->new( ... ); # disable linger $sock->set_option( $SOL_SOCKET, $SO_LINGER, 0, 0 ); # same like $sock->set_option( $SOL_SOCKET, $SO_LINGER, pack( 'S!S!', 0, 0 ) ); # set rcv timeout to 0sec + 100000usec $sock->set_option( $SOL_SOCKET, $SO_RCVTIMEO, 0, 100000 ); # or in milliseconds $sock->set_option( $SOL_SOCKET, $SO_RCVTIMEO, 100 );See Also
- get_option ( $level, $optname )
-
Gets socket options for the socket.
Parameters
$level
The level parameter specifies the protocol level at which the option resides. For example, to retrieve options at the socket level, a level parameter of SOL_SOCKET would be used. Other levels, such as TCP, can be used by specifying the protocol number of that level.
$optname
A valid socket option.
Option Description ----------------------------------------------------------------------------- $SO_DEBUG Reports whether debugging information is being recorded. $SO_ACCEPTCONN Reports whether socket listening is enabled. $SO_BROADCAST Reports whether transmission of broadcast messages is supported. $SO_REUSEADDR Reports whether local addresses can be reused. $SO_KEEPALIVE Reports whether connections are kept active with periodic transmission of messages. If the connected socket fails to respond to these messages, the connection is broken and processes writing to that socket are notified with a SIGPIPE signal. $SO_LINGER Reports whether the socket lingers on close() if data is present. $SO_OOBINLINE Reports whether the socket leaves out-of-band data inline. $SO_SNDBUF Reports send buffer size information. $SO_RCVBUF Reports recieve buffer size information. $SO_ERROR Reports information about error status and clears it. $SO_TYPE Reports the socket type. $SO_DONTROUTE Reports whether outgoing messages bypass the standard routing facilities. $SO_RCVLOWAT Reports the minimum number of bytes to process for socket input operations. ( Defaults to 1 ) $SO_RCVTIMEO Reports the timeout value for input operations. $SO_SNDLOWAT Reports the minimum number of bytes to process for socket output operations. $SO_SNDTIMEO Reports the timeout value specifying the amount of time that an output function blocks because flow control prevents data from being sent.Return Values
Returns the value of the given option, or UNDEF on error. If the size of the value equals the size of int the value will be unpacked as integer. For SO_LINGER, SO_RCVTIMEO and SO_SNDTIMEO the value will be unpacked also. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
use Socket::Class qw($SOL_SOCKET $SO_LINGER $SO_RCVTIMEO); $sock = Socket::Class->new( ... ); # get linger ( $l_onoff, $l_linger ) = $sock->get_option( $SOL_SOCKET, $SO_LINGER ); # get rcv timeout ( $tv_sec, $tv_usec ) = $sock->get_option( $SOL_SOCKET, $SO_RCVTIMEO ); # or in milliseconds $ms = $sock->get_option( $SOL_SOCKET, $SO_RCVTIMEO );See Also
Address Functions
- local_addr ()
-
Returns the local adress of the socket
- local_port ()
-
Returns the local port of the socket
- local_path ()
-
Returns the local path of 'unix' family sockets
- remote_addr ()
-
Returns the remote adress of the socket
- remote_port ()
-
Returns the remote port of the socket
- remote_path ()
-
Returns the remote path of 'unix' family sockets
- pack_addr ( $addr [, $port] )
-
Packs a given address and returns it.
Parameters
$addr
IP address on 'inet' family sockets or a unix path on 'unix' family sockets.
$port
Port number of the address.
Return Values
Returns a packed version of the given address.
Examples
$paddr = $sock->pack_addr( 'localhost', 9999 ); ( $addr, $port ) = $sock->unpack_addr( $paddr ); - unpack_addr ( $paddr )
-
Unpacks a given address and returns it.
Parameters
$paddr
A packed address.
Return Values
Returns the unpacked version of the given address.
Examples
$paddr = $sock->pack_addr( 'localhost', 9999 ); ( $addr, $port ) = $sock->unpack_addr( $paddr ); - get_hostname ( $addr )
-
Resolves the name of a given host address.
Parameters
$addr
The host address in plain (e.g. '192.168.0.1') or packed format.
Return Values
Returns the first hostname found, or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Examples
$str = $sock->get_hostname( '127.0.0.1' ); # -or- $paddr = $sock->pack_addr( '127.0.0.1', 9999 ); $str = $sock->get_hostname( $paddr );
Miscellaneous Functions
- is_readable ( [$timeout] )
-
Does a read select on the socket and returns the result.
Parameters
$timeout
The timeout in milliseconds as a floating point value. If $timeout is initialized to 0, is_readable will return immediately; this is used to poll the readability of the socket. If the value is undef (no timeout), is_readable() can block indefinitely.
Return Values
Return 1 if the socket is readable, or 0 if it is not, or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- is_writable ( [$timeout] )
-
Does a write select on the socket and returns the result.
Parameters
$timeout
The timeout in milliseconds as a floating point value. If $timeout is initialized to 0, is_writable will return immediately; this is used to poll the writability of the socket. If the value is undef (no timeout), is_writable() can block indefinitely.
Return Values
Return 1 if the socket is writable, or 0 if it is not, or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
- select ( [$read [, $write [, $except [, $timeout]]]] )
-
Runs the select() system call on the socket with a specified timeout.
Parameters
$read [in/out]
If the $read parameter is set, the socket will be watched to see if characters become available for reading. Out: Indicates the state of readability.
$write [in/out]
If the $write parameter is set, the socket will be watched to see if a write will not block. Out: Indicates the state of writability.
$except [in/out]
If the $except parameter is set, the socket will be watched for exceptions. Out: Indicates a socket exception.
$timeout
The timeout in milliseconds as a floating point value. If $timeout is initialized to 0, select will return immediately; this is used to poll the state of the socket. If the value is undef (no timeout), select() can block indefinitely.
Return Values
Returns a number between 0 to 3 which indicates the parameters set to TRUE, or UNDEF on error. The error code can be retrieved with errno() and the error string can be retrieved with error().
Remarks
In summary, the socket will be identified in a particular set when select returns if:
read:
If listen has been called and a connection is pending, accept will succeed.
Data is available for reading (includes OOB data if SO_OOBINLINE is enabled).
Connection has been closed/reset/terminated.
write:
If processing a connect call (nonblocking), connection has succeeded.
Data can be sent.
except:
If processing a connect call (nonblocking), connection attempt failed.
OOB data is available for reading (only if SO_OOBINLINE is disabled).
Examples
# watch all states and return within 1 second $v = $sock->select( $r = 1, $w = 1, $e = 1, 1000 ); if( ! defined $v ) { die $sock->error; } if( $e ) { # socket error $e = $sock->get_option( $SOL_SOCKET, $SO_ERROR ); die $sock->error( $e ); } if( $r ) { # socket is readable ... } if( $w ) { # socket is writable ... } - state ()
-
Returns the state of the socket.
Return Values
Number Constant Description --------------------------------------------------- 0 $SOS_INIT Socket is created 1 $SOS_BOUND Socket is bound 2 $SOS_LISTEN Socket is listening 3 $SOS_CONNECTED Socket is connected 4 $SOS_CLOSED Socket is closed 99 $SOS_ERROR Socket got an error on last send or receive - to_string ()
-
Returns a readable version of the socket.
- handle ()
- fileno ()
-
Returns the internal socket handle. fileno is a synonym for handle.
- wait ( $ms )
- sleep ( $ms )
-
Sleeps the given number of milliseconds. sleep is a synonym for wait.
Parameters
$ms
The number of milliseconds to sleep.
Error handling
- is_error ()
-
Indicates a socket error. Returns a true value on socket state SOS_ERROR, or a false value on other states.
- errno ()
-
Returns the last error code.
- error ( [code] )
-
Returns the error message of the error code provided by $code parameter, or from the last occurred error.
MORE EXAMPLES
Internet Server using Threads
use threads;
use threads::shared;
use Socket::Class;
our $RUNNING : shared = 1;
our $Server = Socket::Class->new(
'local_addr' => '0.0.0.0',
'local_port' => 9999,
'listen' => 30,
'blocking' => 0,
'reuseaddr' => 1,
) or die Socket::Class->error;
# catch interrupt signals to provide clean shutdown
$SIG{'INT'} = \&quit;
#$SIG{'TERM'} = \&quit;
threads->create( \&server_thread, $Server );
while( $RUNNING ) {
# do other things here
# ...
# sleep for a while
$Server->wait( 100 );
}
1;
sub quit {
my( $thread );
$RUNNING = 0;
foreach $thread( threads->list ) {
$thread->join();
}
$Server->free();
exit( 0 );
}
sub server_thread {
my( $server ) = @_;
my( $client );
print 'Server running at ' . $server->local_addr .
' port ' . $server->local_port . "\n";
while( $RUNNING ) {
$client = $server->accept();
if( ! defined $client ) {
# server is closed
last;
}
elsif( ! $client ) {
# no connection available, sleep for a while
$server->wait( 10 );
next;
}
threads->create( \&client_thread, $client );
}
return 1;
}
sub client_thread {
my( $client ) = @_;
my( $buf, $got );
print 'Connection from ' . $client->remote_addr .
' port ' . $client->remote_port . "\n";
# do something with the client
$client->set_blocking( 0 );
while( $RUNNING ) {
$got = $client->read( $buf, 4096 );
if( ! defined $got ) {
# error
warn $client->error;
last;
}
elsif( ! $got ) {
# no data available, sleep for a while
$client->wait( 10 );
next;
}
print "Got $got bytes from client\n";
$client->write( 'thank you!' );
}
# close the client and free allocated resources
$client->wait( 50 );
$client->free();
# detach thread
threads->self->detach() if $RUNNING;
return 1;
}AUTHORS
Christian Mueller <christian_at_hbr1.com>
COPYRIGHT
The Socket::Class module is free software. You may distribute under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file.