Can PHP Asynchronously Use Sockets

Can PHP asynchronously use sockets?

Yup, that's what socket_set_nonblock() is for. Your socket interaction code will need to be written differently, taking into account the special meanings that error codes 11, EWOULDBLOCK, and 115, EINPROGRESS, assume.

Here's some somewhat-fictionalized sample code from a PHP sync socket polling loop, as requested:

$buf = '';
$done = false;
do {
    $chunk = socket_read($sock, 4096);
    if($chunk === false) {
        $error = socket_last_error($sock);
        if($error != 11 && $error != 115) {
            my_error_handler(socket_strerror($error), $error);
            $done = true;
        }
        break;
    } elseif($chunk == '') {
        $done = true;
        break;
    } else { 
        $buf .= $chunk;
    }
} while(true);

Open asynchronous sockets in PHP

Use different functions: socket_create() and socket_connect() instead of fsockopen(). This works:

$socks = array();
for ($port = 21; $port <= 25; $port++) {
    $sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    socket_set_nonblock($sock);
    @socket_connect($sock, 'localhost', $port);
    $socks[$port] = $sock;
}

$startTime = microtime(true);
while ($socks && microtime(true) - $startTime < 3) {
    $null = null;
    $write = $socks;
    socket_select($null, $write, $null, 1);
    foreach ($write as $port => $sock) {
        $desc = "$port/tcp";
        $errno = socket_get_option($sock, SOL_SOCKET, SO_ERROR);

        if ($errno == 0) {
            echo "$desc open\n";
        } elseif ($errno == SOCKET_ECONNREFUSED) {
            echo "$desc closed\n";
        } elseif ($errno == SOCKET_ETIMEDOUT) {
            echo "$desc filtered\n";
        } else {
            $errmsg = socket_strerror($errno);
            echo "$desc error $errmsg\n";
        }

        unset($socks[$port]);
        socket_close($sock);
    }
}

foreach ($socks as $port => $sock) {
    $desc = "$port/tcp";
    echo "$desc filtered\n";
    socket_close($sock);
}

How to make asynchronous HTTP requests in PHP

The answer I'd previously accepted didn't work. It still waited for responses. This does work though, taken from How do I make an asynchronous GET request in PHP?

function post_without_wait($url, $params)
{
    foreach ($params as $key => &$val) {
      if (is_array($val)) $val = implode(',', $val);
        $post_params[] = $key.'='.urlencode($val);
    }
    $post_string = implode('&', $post_params);

    $parts=parse_url($url);

    $fp = fsockopen($parts['host'],
        isset($parts['port'])?$parts['port']:80,
        $errno, $errstr, 30);

    $out = "POST ".$parts['path']." HTTP/1.1\r\n";
    $out.= "Host: ".$parts['host']."\r\n";
    $out.= "Content-Type: application/x-www-form-urlencoded\r\n";
    $out.= "Content-Length: ".strlen($post_string)."\r\n";
    $out.= "Connection: Close\r\n\r\n";
    if (isset($post_string)) $out.= $post_string;

    fwrite($fp, $out);
    fclose($fp);
}

Starting Pure PHP socket in Backend/Asynchronously

Solved this, it is not the one that i really want to do, but it's working now properly like what i intended to do from the first place..

Here is how i looks now:

public function __socket_write($text)
{
    $service_port = xxxxxx;

    $address = MyAddress;

    $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

    $result = socket_connect($socket, $address, $service_port);

    if ($result === false) 
    {
        $this->__socket_start();
    } 

    @socket_listen($socket);

    ...

    socket_close($socket);
}

public function __socket_start()
{
    $cmd = "php server.php";

    shell_exec($cmd." > /dev/null 2>/dev/null &");
}

Is there a way to listen for new socket connections while doing a do, while loop in PHP?

I found the solution.
To anyone who was wondering what it was, use:

socket_set_nonblock($socketservervariable);

to make the server not wait for a client to connect before proceeding. That creates a new error though. When doing the client handshake the socket_read wanted a socket but it got the boolean value of false when the socket_accept function didn't detect a client connecting. So this was my solution to that:

$newclient = socket_accept($server);
if($newclient != false){
    handshake($server, $newclient);
    $clients[count($clients)] = $newclient;
    echo "\n\nNew client connected!\n\n";
}

and that solved all of my problems.

How to implement a high performance asynchronous socket server application in PHP?

I think this is a typical case of "If all you have is a hammer, everything looks like a nail."

As you yourself already figured out, php is not the right tool for the job. You can probably find a way to do it anyway, but it'll most likely be messy.

So use the right tool for the job. You would not use a hammer to drive a screw into the wall, would you?

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