©
This document uses PHP Chinese website manual Release
(PHP 4 >= 4.1.0, PHP 5)
socket_write — Write to a socket
$socket
, string $buffer
[, int $length
= 0
] )
The function socket_write() writes to the
socket
from the given
buffer
.
socket
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 than the buffer length, it is silently truncated to the length
of the buffer.
Returns the number of bytes successfully written to the socket 或者在失败时返回 FALSE
.
The error code can be retrieved with
socket_last_error() . This code may be passed to
socket_strerror() to get a textual explanation of the
error.
Note:
It is perfectly valid for socket_write() to return zero which means no bytes have been written. Be sure to use the === operator to check for
FALSE
in case of an error.
Note:
socket_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.
[#1] php at deguest dot asia [2015-05-03 08:58:39]
I often read in php docs users not checking for the php function returned value, and in the case of socket_write, I could not see here in the comment anyone botering to read on the socket the server reply.
Then one user thought it would be a good idea to use usleep after a socket_write on a smtp connection.
Actually, if you check the server reply, not only will it give time for the server to reply before you write again on the socket, but also this is a great opportunity to check what the server replied you.
For instance, for smtp connection :
In this example MAIL_SERVER, MAIL_PORT and DEBUG are constants I defined.
<?php
function sendmail( $param )
{
$from = &$param[ 'from' ];
$to = &$param[ 'to' ];
$message = &$param[ 'data' ];
$isError = function( $string )
{
if( preg_match( '/^((\d)(\d{2}))/', $string, $matches ) )
{
if( $matches[ 2 ] == 4 || $matches[ 2 ] == 5 ) return( $matches[ 1 ] );
}
else
{
return( false );
}
};
try
{
$socket = null;
if( ( $socket = socket_create( AF_INET, SOCK_STREAM, SOL_TCP ) ) == false )
{
throw new Exception( sprintf( "Unable to create a socket: %s", socket_strerror( socket_last_error() ) ) );
}
if( !socket_connect( $socket, MAIL_SERVER, MAIL_PORT ) )
{
throw new Exception( sprintf( "Unable to connect to server %s: %s", MAIL_SERVER, socket_strerror( socket_last_error() ) ) );
}
$read = socket_read( $socket, 1024 );
if( $read == false )
{
throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );
}
if( socket_write( $socket, sprintf( "HELO %s\r\n", gethostname() ) ) === false )
{
throw new Exception( sprintf( "Unable to write to socket: %s", socket_strerror( socket_last_error() ) ) );
}
$read = socket_read( $socket, 1024 );
if( $read == false )
{
throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );
}
else
{
if( ( $errCode = $isError( $read ) ) ) throw new Exception( "Server responded with an error code $errCode" );
}
if( socket_write( $socket, sprintf( "MAIL FROM: %s\r\n", $from ) ) === false )
{
throw new Exception( sprintf( "Unable to write to socket: %s", socket_strerror( socket_last_error() ) ) );
}
$read = socket_read( $socket, 1024 );
if( $read == false )
{
throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );
}
else
{
if( ( $errCode = $isError( $read ) ) ) throw new Exception( "Server responded with an error code $errCode" );
}
return( $totalWriten );
}
catch( Exception $e )
{
$ERROR = sprintf( "Error sending mail message at line %d. ", $e->getLine() ) . $e->getMessage();
return( false );
}
}
[#2] divinity76 at gmail dot com [2015-02-06 17:14:15]
function AddTCPChecksum(&$data){
//feel free to add some error handling for strlen($data)>65535...
$data=pack("v",strlen($data)).$data;
}
[#3] jean at briskula dot si [2011-02-03 15:00:31]
Some clients (Flash's XMLSocket for example) won't fire a read event until a new line is recieved.
<?php
function write(&$sock,$msg) {
$msg = "$msg\n\0";
$length = strlen($msg);
while(true) {
$sent = socket_write($sock,$msg,$length);
if($sent === false) {
return false;
}
if($sent < $length) {
$msg = substr($msg, $sent);
$length -= $sent;
print("Message truncated: Resending: $msg");
} else {
return true;
}
}
return false;
}
?>
[#4] revelable at hotmail dot com [2010-12-20 17:08:08]
Here we have the same function to write a socket but with improved performance.
If the messager are not larger, they will be written entirely with a single socket_write() call. And is not needed to call the substr() function for the first bucle.
<?php
$st="Message to sent";
$length = strlen($st);
while (true) {
$sent = socket_write($socket, $st, $length);
if ($sent === false) {
break;
}
// Check if the entire message has been sented
if ($sent < $length) {
// If not sent the entire message.
// Get the part of the message that has not yet been sented as message
$st = substr($st, $sent);
// Get the length of the not sented part
$length -= $sent;
} else {
break;
}
}
?>
[#5] masterwaster at gmail dot com [2008-08-26 11:42:03]
Hi,
if you got same problems like i have
<?php
@socket_write($xd, "Good Bye!\n\r");
@socket_shutdown($xd, 2);
@socket_close($xd);
?>
wont'tx send "Good Bye!\n\r" to the opened socket.
but if you put a
usleep or something like echo "";
between write and shutdown its working.
[#6] webmaster at you-are-infected dot com [2006-08-23 10:27:23]
If you connect to a Server in a way like you do with telnet or some similar protokoll you may have problems with sending data to the server. I found out that at some servers there is a different between:
<?php
socket_write ($my_socket, $line, strlen ($line));
socket_write ($my_socket, "\r\n", strlen ("\r\n"));
?>
witch worked at least, and
<?php
socket_write ($my_socket, $line."\r\n", strlen ($line."\r\n"));
?>
wich made the server stop sending any data.
I hope this helps to save a lot of time. I needed about two days to find out, that this was the problem ;)
[#7] gtk at linux dot online dot no [2002-08-20 04:43:42]
from http://www.manualy.sk/sock-faq/unix-socket-faq-2.html
read() is equivalent to recv() with a flags parameter of 0. Other values for the flags parameter change the behaviour of recv(). Similarly, write() is equivalent to send() with flags == 0.