[Sussex] Sockets interface in PHP

[Oli]

Hi Brendan,

You need to set the O_NONBLOCK option on the socket just after you
create it and also trap the error you'll get from socket_read when it
returns no data.  I'm afraid I don't know the PHP calls exactly for this
offhand.

:-)

HTH,

-Oli

Brendan Whelan wrote:
> I am developing a sockets interface, in PHP running under Fedora Core 5,
> to receive requests and return data. See below is the program in its
> most basic form. It accepts requests and returns data but the
> program waits on the socket_read and only moves on when either data is
> received or the sending system terminates the connection. This means
> that other users/systems cannot gain access. I have hunted around the
> Internet and tried various combinations without success. 
>  
> Any suggestions?
>  
> Thanks, Brendan  
>  
> #!/usr/local/bin/php -q
> <?php
> // Simple sockets receive program
> error_reporting (E_ALL);
>  
> /* Allow the script to hang around waiting for connections. */
> set_time_limit (0);
>  
> /* Turn on implicit output flushing so we see what we're getting
>  * as it comes in. */
> ob_implicit_flush ();
> print "Started\n";
>  
> $address = '192.168.40.19';
> // PORT NEEDS TO BE PERMITTED THROUGH FIREWALL
> $port = 21244;
>  
> if (($sock = socket_create (AF_INET, SOCK_STREAM, 0)) < 0) {
>     echo "socket_create() failed: reason: " . socket_strerror ($sock) .
> "\n";
> }
>  
> if (($ret = socket_bind ($sock, $address, $port)) < 0) {
>     echo "socket_bind() failed: reason: " . socket_strerror ($ret) . "\n";
> }
>  
> if (($ret = socket_listen ($sock, 5)) < 0) {
>     echo "socket_listen() failed: reason: " . socket_strerror ($ret) . "\n";
> }
>  
> do {
> print "In loop\n";
>     if (($msgsock = socket_accept($sock)) < 0) {
>         echo "socket_accept() failed: reason: " . socket_strerror
> ($msgsock) . "\n";
>         break;
>     }
> print "After accept\n";
>     /* Send instructions. */
>     $msg = "\nWelcome to the PHP Test Server. \n" .
>         "To quit, type 'quit'. To shut down the server type 'shutdown'.\n";
>     socket_write($msgsock, $msg, strlen($msg));
> print "Above inner loop\n";
>     do {
>         if (FALSE === ($buf = socket_read ($msgsock, 2048,
> PHP_NORMAL_READ))) {
>             echo "socket_read() failed: reason: " . socket_strerror
> ($ret) . "\n";
>             break 2;
>         }
>         if (!$buf = trim ($buf)) {
>             continue;
>         }
>         if ($buf == 'quit') {
>             break;
>         }
>         if ($buf == 'shutdown') {
>             socket_close ($msgsock);
>             break 2;
>         }
>         $talkback = "PHP: You said '$buf'.\n";
>         socket_write ($msgsock, $talkback, strlen ($talkback));
>         echo "$buf\n";
>     } while (true);
>     socket_close ($msgsock);
> } while (true);
>  
> socket_close ($sock);
> ?>
> 
> 
> ------------------------------------------------------------------------
> 
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> E-mail Address: sussex at mailman.lug.org.uk
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Oli Comber
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