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socket_accept

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

socket_acceptAccepte une connexion sur un socket

Description

socket_accept(Socket $socket): Socket|false

Une fois que le socket socket a été créé avec la fonction socket_create(), lié à un nom avec la fonction socket_bind(), et mis en attente de connexion avec la fonction socket_listen(), socket_accept() va accepter les connexions sur ce socket. Une fois qu'une connexion est faite, une nouvelle instance de Socket est retournée. Elle peut être utilisée pour les communications. S'il y a plusieurs connexions en attente, la première sera utilisée. S'il n'y a pas de connexion en attente, socket_accept() se bloquera jusqu'à ce qu'une connexion se présente. Si socket a été rendue non-bloquante, grâce à socket_set_blocking() ou socket_set_nonblock(), false sera retourné.

L'instance de Socket retournée par socket_accept() ne doit pas être utilisée pour accepter de nouvelles connexions. Le socket original socket, qui est en attente, reste ouvert et peut être réutilisé.

Liste de paramètres

socket

Une instance de Socket créée par socket_create().

Valeurs de retour

Retourne une nouvelle instance de Socket en cas de succès ou false en cas d'erreur. Le code d'erreur généré peut être obtenu en appelant la fonction socket_last_error(). Ce code d'erreur peut être passé à la fonction socket_strerror() pour obtenir un message d'erreur, humainement lisible.

Historique

Version Description
8.0.0 En cas de succès, cette fonction retourne désormais une instance de Socket ; auparavant, une resource était retournée.

Voir aussi

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User Contributed Notes 7 notes

up
24
lars at opdenkamp dot eu
16 years ago
If you want to make a daemon process that forks on each client connection, you'll find out that there's a bug in PHP. The child processes send SIGCHLD to their parent when they exit but the parent can't handle signals while it's waiting for socket_accept (blocking).

Here is a piece of code that makes a non-blocking forking server.

#!/usr/bin/php -q
<?php
/**
* Listens for requests and forks on each connection
*/

$__server_listening = true;

error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();
declare(
ticks = 1);

become_daemon();

/* nobody/nogroup, change to your host's uid/gid of the non-priv user */
change_identity(65534, 65534);

/* handle signals */
pcntl_signal(SIGTERM, 'sig_handler');
pcntl_signal(SIGINT, 'sig_handler');
pcntl_signal(SIGCHLD, 'sig_handler');

/* change this to your own host / port */
server_loop("127.0.0.1", 1234);

/**
* Change the identity to a non-priv user
*/
function change_identity( $uid, $gid )
{
if( !
posix_setgid( $gid ) )
{
print
"Unable to setgid to " . $gid . "!\n";
exit;
}

if( !
posix_setuid( $uid ) )
{
print
"Unable to setuid to " . $uid . "!\n";
exit;
}
}

/**
* Creates a server socket and listens for incoming client connections
* @param string $address The address to listen on
* @param int $port The port to listen on
*/
function server_loop($address, $port)
{
GLOBAL
$__server_listening;

if((
$sock = socket_create(AF_INET, SOCK_STREAM, 0)) < 0)
{
echo
"failed to create socket: ".socket_strerror($sock)."\n";
exit();
}

if((
$ret = socket_bind($sock, $address, $port)) < 0)
{
echo
"failed to bind socket: ".socket_strerror($ret)."\n";
exit();
}

if( (
$ret = socket_listen( $sock, 0 ) ) < 0 )
{
echo
"failed to listen to socket: ".socket_strerror($ret)."\n";
exit();
}

socket_set_nonblock($sock);

echo
"waiting for clients to connect\n";

while (
$__server_listening)
{
$connection = @socket_accept($sock);
if (
$connection === false)
{
usleep(100);
}elseif (
$connection > 0)
{
handle_client($sock, $connection);
}else
{
echo
"error: ".socket_strerror($connection);
die;
}
}
}

/**
* Signal handler
*/
function sig_handler($sig)
{
switch(
$sig)
{
case
SIGTERM:
case
SIGINT:
exit();
break;

case
SIGCHLD:
pcntl_waitpid(-1, $status);
break;
}
}

/**
* Handle a new client connection
*/
function handle_client($ssock, $csock)
{
GLOBAL
$__server_listening;

$pid = pcntl_fork();

if (
$pid == -1)
{
/* fork failed */
echo "fork failure!\n";
die;
}elseif (
$pid == 0)
{
/* child process */
$__server_listening = false;
socket_close($ssock);
interact($csock);
socket_close($csock);
}else
{
socket_close($csock);
}
}

function
interact($socket)
{
/* TALK TO YOUR CLIENT */
}

/**
* Become a daemon by forking and closing the parent
*/
function become_daemon()
{
$pid = pcntl_fork();

if (
$pid == -1)
{
/* fork failed */
echo "fork failure!\n";
exit();
}elseif (
$pid)
{
/* close the parent */
exit();
}else
{
/* child becomes our daemon */
posix_setsid();
chdir('/');
umask(0);
return
posix_getpid();

}
}

?>
up
18
Boylett
15 years ago
If you want to have multiple clients on a server you will have to use non blocking.

<?php

$clients
= array();
$socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
socket_bind($socket,'127.0.0.1',$port);
socket_listen($socket);
socket_set_nonblock($socket);

while(
true)
{
if((
$newc = socket_accept($socket)) !== false)
{
echo
"Client $newc has connected\n";
$clients[] = $newc;
}
}

?>
up
4
Greg MacLellan
20 years ago
The socket returned by this resource will be non-blocking, regardless of what the listening socket is set to. This is actually true for all FCNTL modifiers.
up
2
renmengyang567 at gmail dot com
4 years ago
<explain>
This case is a very simple interaction between the TCP client side and the TCP server side

<?php
// create for simple-tcp-server
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_bind($sock, '127.0.0.1',5000);
socket_listen($sock,1);
$clnt_sock = socket_accept($sock); //阻塞
$st = "hello world ^_^";
socket_write($clnt_sock, $st,strlen($st));
socket_close($clnt_sock);
socket_close($sock);
?>

<?php
//create for simple-tcp-client
$clnt_sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_connect($clnt_sock, '127.0.0.1', 5000);
$ret= socket_read($clnt_sock, 1024);
print
"from simple-tcp-server:".$ret.PHP_EOL;
socket_close($clnt_sock);
?>

<fruit>
from simple-tcp-server:hello world ^_^
up
-1
gmkarl at gmail dot com
16 years ago
Be aware signal handler functions set with pcntl_signal are not called while a socket is blocking waiting for a connection; the signal is absorbed silently and the handler called when a connection is made.
up
-7
simon at 180solutions dot com
18 years ago
>Accepting a connection using php-sockets:
>
>$fd = socket_create(AF_INET, SOCK_STREAM, 6 /* OR >getprotobyname("TCP")*/);
>
>$PORT = 5000;
>
>socket_bind($fd, "0.0.0.0", $PORT);
>
>while(true)
>{
>$remote_fd = socket_accept($fd);
>
>remote_socket_client_handle($remote_fd);
>
>}
>
>It is simple!

This example doesn't work. You have to call socket_listen($fd) after your bind in order to accept incoming connections.

Simon
up
-8
mightyplow at gmail dot com
9 years ago
In order to make many clients connectable to the server, you have to set the accepted socket also to non-blocking. Otherwise the accepted connection will block further incoming connections.

while (true) {
$newSock = @socket_accept($sock);

if ($newSock) {
echo 'client connected';

socket_set_nonblock($newSock);
}
}
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