PHP Writing daemon process details and instance code _php example

This afternoon in segmentfault.com to see a question, ask the title is "How To do PHP service", which asked whether PHP can only be called on the web. In fact, many people have misunderstood the use of PHP scenarios, that PHP can only be used to write web scripts, in fact, starting from PHP4, PHP's use of the scene has long been not limited to processing Web requests. From the PHP architecture, PHP is divided into three levels: SAPI, PHP core and Zend engine. The PHP core itself is not coupled with the web, and PHP communicates with other applications via SAPI, such as mod_php, which is a SAPI implementation for Apache, and FPM is a fastcgi implementation based on the SAPI protocol, which is the SAPI of the Web Server to work with Web requests. But there are a lot of SAPI that are not web-like, such as the CLI SAPI can enable direct execution of php,embed in a command-line environment SAPI can embed PHP in other languages (such as LUA). I'm not going to discuss the architecture and SAPI of PHP in detail here, just to show that PHP is already designed to support a variety of environments, rather than web-specific, from the architecture perspective. In addition to the support of the architecture system, PHP's rich extension modules also provide the backing for PHP to work in different environments, such as the Pcntl module and the POSIX module to implement basic process management, signal processing and other operating system-level functions. And the sockets module enables PHP to have socket communication capabilities. So PHP can be used to write tool scripts like Shell or Perl, even daemon process with a server nature. To show how PHP writes daemon server, I wrote a simple HTTP server in PHP that runs in the form of a daemon process. Of course, in order to focus on how to write daemon in PHP, I did not implement the specific business logic for this HTTP server, but it can listen to the specified port, accept the HTTP request and return to the client a fixed text, the whole process through the socket implementation, all from PHP written.

Code instances

Here is the complete code for this program:

<?php//accpet the HTTP client request and generate response content.
As a demo, this function just send "PHP HTTP Server" to client.
  function Handle_http_request ($address, $port) {$max _backlog = 16; $res _content = "http/1.1 ok content-length:15 content-type:text/plain;
  Charset=utf-8 PHP HTTP Server ";
 
  $res _len = strlen ($res _content); Create, bind and listen to socket if (($socket = Socket_create (Af_inet, Sock_stream, sol_tcp)) = = FALSE) {echo
    "Create socket failed!\n";
  Exit
    } if ((Socket_bind ($socket, $address, $port)) = = FALSE) {echo bind socket failed!\n;
  Exit
    if ((Socket_listen ($socket, $max _backlog)) = = FALSE) {echo "Listen to socket failed!\n";
  Exit
    }//loop while (TRUE) {if ($accept _socket = socket_accept ($socket)) = = FALSE) {continue;  
      else {socket_write ($accept _socket, $res _content, $res _len);
    Socket_close ($accept _socket); }
  }
}
 
//Run as daemon process. function Run () {if ($pid 1 = pcntl_fork ()) = = 0)//first child process {posix_setsid ();//set the child proc
     
    ESS as the session leader.
    if ($pid 2 = pcntl_fork () = = 0)//second child process, which run as daemon.
      {//replaced with your own domain or address. 
    Handle_http_request (' www.codinglabs.org ', 9999);
      else {//first child process exit;
    Exit
    } else {//wait for the ' the '.
  Pcntl_wait ($status);
}//entry point.
 
Run ();
 ?>

Here I assume that you have a better understanding of UNIX environment programming, so do not do too many details of the explanation, just comb it. In simple terms, this program consists of two parts, the Handle_http_request function is responsible for processing HTTP requests, which are written in the same way as TCP server written in C: creating sockets, binding, listening, Then through a loop to handle each connect over the client, once accept to a connection ...

Thank you for reading, I hope to help you, thank you for your support for this site!