Alternative Way To Resolve Stream_select You Must Recompile Php With A Larger Value Of Fd_setsize Issue Without Recompiling Php

I met a boring issue when adding websocket to a PHP site by using Ratchet (A PHP websocket framework):

“It is set to 1024, but you have descriptors numbered at least as high as 1266.

–enable-fd-setsize=2048 is recommended, but you may want to set it to equal the maximum number of open files supported by your system”

I struggled and googled it, finally found a bad news: FD_SIZE is set to 1024 in the PHP source code. The error occurs if the web socket connections are over 1024. I don’t want to modify the PHP source code and recompile it, which may cause unexpected issue. So I try to find another way to solve this issue. Fortunately, I found it.

Basically, I’m opening multiple websocket service processes in the server, and each process has different port. In the front end, I wrote a js function to choose different port to connect. That means we have 1024 * n availiable connections now. Let’s go to the details.

Back-end implementation

Write a websocket service called push-server.php. Please refer to Ratchet’s example. However, we need make the php file to accept a port parameter:

$port = $argv[1];

if ($port == ""){

$port = 40003; // Default port

}

// .....Ignoring other code .....

// Passing port paramter.

$webSock->listen($port, '0.0.0.0');

Now we can start multiple websocket processes with different ports, for instance: php push-server 40003 php push-server 40004 php push-server 40005 The server can have 1024 * 3 = 3072 websocket connections now. Front-end implementation The js code to connect websocket service randomly:

function getWSServer() {
    var serverPorts = ['40003', '40004', '40005'];
    var server = 'ws://youhost';
    var randomPortIndex = Math.floor(Math.random() * serverPorts.length);

    server += ':' + serverPorts[randomPortIndex];

    return server;
};

Written on February 8, 2014