Introduction to three methods of php multi-thread simulation implementation

When we were working on the project, we had some requirements, especially the response processing of data that took a lot of time. We all know that PHP itself does not support multi-threading, so how should we implement multi-threading in PHP?

1. PHP multi-threading under Linux

The following things are derived from the pcntl_fork function of PHP. Because of this The function depends on the implementation of the operating system fork, so the things described in this article only apply to Linux/Unix. So let’s take a look at the usage of this function first. php manual says this:

<?php
$pid = pcntl_fork();if ($pid == -1) {         
die(&#39;could not fork&#39;);
} else if ($pid) {         
// we are the parent
         pcntl_wait($status); /
/Protect against Zombie children} else {         
// we are the child}?>

Create a child process through pcntl_fork, if the return value If it is -1, then it means that the creation of the child process failed. The successfully created process ID will be returned to the parent process, and 0 will be returned to the child process. It is difficult to understand, so it should be written like this:

<?php
$pid = pcntl_fork();if($pid == -1){         //创建失败咱就退出呗,没啥好说的
         die(&#39;could not fork&#39;);
}else{        if($pid){                //从这里开始写的代码是父进程的,因为写的是系统程序,记得退出的时候给个返回值
                exit(0);
        }        else{                //从这里开始写的代码都是在新的进程里执行的,同样正常退出的话,最好也给一个返回值
                exit(0);
        }
}?>

It will be better to change it this way I understand better. If your parent process wants to know that the child process exits normally, you can add the previous pcntl_wait.

2. Through stream_socket_client method

function sendStream() { 
    $english_format_number = number_format($number, 4, '.', ''); 
  
    echo $english_format_number;  
    exit(); 
    $timeout = 10; 
    $result = array(); 
    $sockets = array(); 
    $convenient_read_block = 8192; 
    $host = "test.local.com"; 
    $sql = "select waybill_id,order_id from xm_waybill where status>40 order by update_time desc limit 1 ";  
    $data = Yii::app()->db->createCommand($sql)->queryAll(); 
    $id = 0; 
  
    foreach ($data as $k => $v) { 
      if ($k % 2 == 0) { 
        $send_data[$k]['body'] = NoticeOrder::getSendData($v['waybill_id']); 
  
      } else { 
        $send_data[$k]['body'] = array($v['order_id'] => array('extra' => 16));  
      }  
      $data = json_encode($send_data[$k]['body']); 
      $s = stream_socket_client($host . ":80", $errno, $errstr, $timeout, STREAM_CLIENT_ASYNC_CONNECT | STREAM_CLIENT_CONNECT); 
      if ($s) {  
        $sockets[$id++] = $s; 
        $http_message = "GET /php/test.php?data=" . $data . " HTTP/1.0\r\nHost:" . $host . "\r\n\r\n";  
        fwrite($s, $http_message); 
      } else {  
        echo "Stream " . $id . " failed to open correctly."; 
      }  
    } 
  
    while (count($sockets)) { 
  
      $read = $sockets; 
  
      stream_select($read, $w = null, $e = null, $timeout); 
       if (count($read)) {  
        /* stream_select generally shuffles $read, so we need to 
         compute from which socket(s) we're reading. */
        foreach ($read as $r) { 
  
          $id = array_search($r, $sockets); 
          $data = fread($r, $convenient_read_block); 
          if (strlen($data) == 0) { 
            echo "Stream " . $id . " closes at " . date(&#39;h:i:s&#39;) . ".<br>  "; 
            fclose($r); 
             unset($sockets[$id]); 
          } else { 
            $result[$id] = $data; 
          } 
        } 
      } else {  
        /* A time-out means that *all* streams have failed 
         to receive a response. */
        echo "Time-out!\n"; 
        break; 
      }  
    }  
    print_r($result); 
  
  }

3. Through multi-process instead of multi-thread

function daemon($func_name,$args,$number){ 
  while(true){ 
    $pid=pcntl_fork(); 
    if($pid==-1){ 
      echo "fork process fail"; 
      exit(); 
    }elseif($pid){//创建的子进程 
  
      static $num=0; 
      $num++; 
      if($num>=$number){ 
        //当进程数量达到一定数量时候，就对子进程进行回收。 
        pcntl_wait($status); 
  
        $num--; 
      }  
    }else{ //为0 则代表是子进程创建的，则直接进入工作状态 
  
      if(function_exists($func_name)){ 
        while (true) { 
          $ppid=posix_getpid(); 
          var_dump($ppid); 
          call_user_func_array($func_name,$args); 
          sleep(2); 
        } 
      }else{ 
        echo "function is not exists"; 
      } 
      exit();   
    } 
  } 
}  function worker($args){  
  //do something 
  }  
daemon('worker',array(1),2);

Summary:

Multi-threading cannot be used in php. In fact, we all know it. But we can achieve it through many methods. This article introduces the multi-threading implementation method in PHP. Hope this helps!

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