socket_write
(PHP 4 >= 4.1.0, PHP 5)
socket_write — Write to a socket
Description
$socket
, string $buffer
[, int $length = 0
] )
The function socket_write() writes to the
socket from the given
buffer.
Parameters
-
socket -
-
buffer -
The buffer to be written.
-
length -
The optional parameter
lengthcan 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.
Return Values
Returns the number of bytes successfully written to the socket or FALSE on failure.
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
FALSEin case of an error.
Notes
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.
See Also
- socket_accept() - Accepts a connection on a socket
- socket_bind() - Binds a name to a socket
- socket_connect() - Initiates a connection on a socket
- socket_listen() - Listens for a connection on a socket
- socket_read() - Reads a maximum of length bytes from a socket
- socket_strerror() - Return a string describing a socket error
- socket_accept
- socket_bind
- socket_clear_error
- socket_close
- socket_cmsg_space
- socket_connect
- socket_create_listen
- socket_create_pair
- socket_create
- socket_get_option
- socket_getopt
- socket_getpeername
- socket_getsockname
- socket_import_stream
- socket_last_error
- socket_listen
- socket_read
- socket_recv
- socket_recvfrom
- socket_recvmsg
- socket_select
- socket_send
- socket_sendmsg
- socket_sendto
- socket_set_block
- socket_set_nonblock
- socket_set_option
- socket_setopt
- socket_shutdown
- socket_strerror
- socket_write
Коментарии
from http://www.manualy.sk/sock-faq/unix-socket-faq-2.htmlread() 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.
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 ;)
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;
}
}
?>
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" );
}
/* And some more code, but not enough place in comment */
return( $totalWriten );
}
catch( Exception $e )
{
$ERROR = sprintf( "Error sending mail message at line %d. ", $e->getLine() ) . $e->getMessage();
return( false );
}
}
sending a few mbs or more results in incomplete transfers, send data in a loop and chunks instead, socket_write reports complete write even though it is only a partial transfer, possibly because of buffer overrun somewhere.
$strlen=strlen($msg);
$totaltransferred=0;
$blocksize=10000;
for ($a=0;$a<$strlen;$a+=$blocksize){
$part=substr($msg,$a,$blocksize);
$transferred=socket_write($socket,$part,strlen($part));
$totaltransferred+=$transferred;
}
if ($totaltransferred<$strlen){
echo "incomplete transfer";
}