PHP多线程的实现方法详解

发布:smiling　来源: PHP粉丝网　添加日期：2014-08-27 17:07:56　浏览: 评论：0　

多线程是java中一个很不错的东西,很多朋友说在php中不可以使用PHP多线程了,其实那是错误的说法PHP多线程实现方法和fsockopen函数有关,下面我们来介绍具体实现程序代码,有需要了解的同学可参考.

当有人想要实现并发功能时,他们通常会想到用fork或者spawn threads,但是当他们发现php不支持多线程的时候,大概会转换思路去用一些不够好的语言,比如perl.

其实的是大多数情况下,你大可不必使用 fork 或者线程,并且你会得到比用 fork 或 thread 更好的性能.

假设你要建立一个服务来检查正在运行的n台服务器,以确定他们还在正常运转,你可能会写下面这样的代码:

<?php

$hosts = array("host1.sample.com", "host2.sample.com", "host3.sample.com");

$timeout = 15;

$status = array();

foreach ($hosts as $host) {

$errno = 0;

$errstr = "";

$s = fsockopen($host, 80, $errno, $errstr, $timeout);

if ($s) {

  $status[$host] = "Connectedn";

  fwrite($s, "HEAD / HTTP/1.0rnHost: $hostrnrn");

  do {

   $data = fread($s, 8192);

   if (strlen($data) == 0) {

   break;

   }

   $status[$host] .= $data;

  } while (true);

  fclose($s);

} else {

  $status[$host] = "Connection failed: $errno $errstrn";

}

}

print_r($status);

?>

它运行的很好,但是在fsockopen()分析完hostname并且建立一个成功的连接,或者延时$timeout秒之前,扩充这段代码来管理大量服务器将耗费很长时间.

因此我们必须放弃这段代码,我们可以建立异步连接-不需要等待fsockopen返回连接状态。PHP仍然需要解析hostname,所以直接使用ip更加明智,不过将在打开一个连接之后立刻返回,继而我们就可以连接下一台服务器.

有两种方法可以实现,PHP5中可以使用新增的stream_socket_client()函数直接替换掉fsocketopen(),PHP5之前的版本,你需要自己动手,用sockets扩展解决问题.

下面是PHP5中的解决方法,代码如下:

<?php

$hosts = array("host1.sample.com", "host2.sample.com", "host3.sample.com");

$timeout = 15;

$status = array();

$sockets = array();

/* Initiate connections to all the hosts simultaneously */

foreach ($hosts as $id => $host) {

$s = stream_socket_client("

$

$host:80", $errno, $errstr, $timeout,

  STREAM_CLIENT_ASYNC_CONNECT|STREAM_CLIENT_CONNECT);

if ($s) {

  $sockets[$id] = $s;

  $status[$id] = "in progress";

} else {

  $status[$id] = "failed, $errno $errstr";

}

}

/* Now, wait for the results to come back in */

while (count($sockets)) {

$read = $write = $sockets;

/* This is the magic function - explained below */

$n = stream_select($read, $write, $e = null, $timeout);

if ($n > 0) {

  /* readable sockets either have data for us, or are failed

   * connection attempts */

  foreach ($read as $r) {

      $id = array_search($r, $sockets);

      $data = fread($r, 8192);

      if (strlen($data) == 0) {

   if ($status[$id] == "in progress") {

    $status[$id] = "failed to connect";

   }

   fclose($r);

   unset($sockets[$id]);

      } else {

   $status[$id] .= $data;

      }

  }

  /* writeable sockets can accept an HTTP request */

  foreach ($write as $w) {

   $id = array_search($w, $sockets);

   fwrite($w, "HEAD / HTTP/1.0rnHost: "

    . $hosts[$id] .  "rnrn");

   $status[$id] = "waiting for response";

  }

} else {

  /* timed out waiting; assume that all hosts associated

   * with $sockets are faulty */

  foreach ($sockets as $id => $s) {

   $status[$id] = "timed out " . $status[$id];

  }

  break;

}

}

foreach ($hosts as $id => $host) {

echo "Host: $hostn";

echo "Status: " . $status[$id] . "nn";

}

?>

我们用stream_select()等待sockets打开的连接事件,stream_select()调用系统的select(2)函数来工作,前面三个参数是你要使用的streams的数组,你可以对其读取,写入和获取异常,分别针对三个参数,stream_select()可以通过设置$timeout（秒）参数来等待事件发生-事件发生时,相应的sockets数据将写入你传入的参数.

下面是PHP4.1.0之后版本的实现,如果你已经在编译PHP时包含了sockets(ext/sockets)支持，你可以使用根上面类似的代码,只是需要将上面的streams/filesystem函数的功能用ext/sockets函数实现,主要的不同在于我们用下面的函数代替stream_socket_client()来建立连接,代码如下:

<?php

// This value is correct for Linux, other systems have other values

define('EINPROGRESS', 115);

function non_blocking_connect($host, $port, &$errno, &$errstr, $timeout) {

$ip = gethostbyname($host);

$s = socket_create(AF_INET, SOCK_STREAM, 0);

if (socket_set_nonblock($s)) {

  $r = @socket_connect($s, $ip, $port);

  if ($r || socket_last_error() == EINPROGRESS) {

   $errno = EINPROGRESS;

   return $s;

  }

}

$errno = socket_last_error($s);

$errstr = socket_strerror($errno);

socket_close($s);

return false;

}

?>

现在用socket_select()替换掉stream_select(),用socket_read()替换掉fread(),用socket_write()替换掉fwrite(),用socket_close()替换掉fclose()就可以执行脚本了.

PHP5的先进之处在于,你可以用stream_select()处理几乎所有的stream-例如你可以通过include STDIN用它接收键盘输入并保存进数组,你还可以接收通过proc_open()打开的管道中的数据.

下面来分享一个PHP多线程类,代码如下:

* @title:      PHP多线程类(Thread)

* @version:    1.0

* @author:     phper.org.cn < web@phper.org.cn >

* @published:  2010-11-2

*

* PHP多线程应用示例：

*  require_once 'thread.class.php';

*  $thread = new thread();

*  $thread->addthread('action_log','a');

*  $thread->addthread('action_log','b');

*  $thread->addthread('action_log','c');

*  $thread->runthread();

*

*  function action_log($info) {

*      $log = 'log/' . microtime() . '.log';

*      $txt = $info . "rnrn" . 'Set in ' . Date('h:i:s', time()) . (double)microtime() . "rn";

*      $fp = fopen($log, 'w');

*      fwrite($fp, $txt);

*      fclose($fp);

*  }

*/

lass thread {

   var $hooks = array();

   var $args = array();

   function thread() {

   }

   function addthread($func)

   {

       $args = array_slice(func_get_args(), 1);

       $this->hooks[] = $func;

       $this->args[] = $args;

       return true;

   }

   function runthread()

   {

       if(isset($_GET['flag']))

       {

           $flag = intval($_GET['flag']);

       }

       if($flag || $flag === 0)

       {

           call_user_func_array($this->hooks[$flag], $this->args[$flag]);

       }

       else

       {

           for($i = 0, $size = count($this->hooks); $i < $size; $i++)

           {

               $fp=fsockopen($_SERVER['HTTP_HOST'],$_SERVER['SERVER_PORT']);//开源代码phpfensi.com

               if($fp)

               {

                   $out = "GET {$_SERVER['PHP_SELF']}?flag=$i HTTP/1.1rn";

                   $out .= "Host: {$_SERVER['HTTP_HOST']}rn";

                   $out .= "Connection: Closernrn";

                   fputs($fp,$out);

                   fclose($fp);

               }

           }

       }

   }