PHP多線程的實現方法詳解

2024-05-04 21:48:32

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多線程是java中一個很不錯的東西,很多朋友說在php中不可以使用PHP多線程了,其實那是錯誤的說法PHP多線程實現方法和fsockopen函數有關,下面我們來介紹具體實現程序代碼,有需要了解的同學可參考.

當有人想要實現并發功能時,他們通常會想到用fork或者spawn threads,但是當他們發現php不支持多線程的時候,大概會轉換思路去用一些不夠好的語言,比如perl.

其實的是大多數情況下,你大可不必使用 fork 或者線程,并且你會得到比用 fork 或 thread 更好的性能.

假設你要建立一個服務來檢查正在運行的n臺服務器,以確定他們還在正常運轉,你可能會寫下面這樣的代碼:

<?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);

?>

它運行的很好,但是在fsockopen()分析完hostname并且建立一個成功的連接,或者延時$timeout秒之前,擴充這段代碼來管理大量服務器將耗費很長時間.

因此我們必須放棄這段代碼,我們可以建立異步連接-不需要等待fsockopen返回連接狀態。PHP仍然需要解析hostname,所以直接使用ip更加明智,不過將在打開一個連接之后立刻返回,繼而我們就可以連接下一臺服務器.

有兩種方法可以實現,PHP5中可以使用新增的stream_socket_client()函數直接替換掉fsocketopen(),PHP5之前的版本,你需要自己動手,用sockets擴展解決問題.

下面是PHP5中的解決方法,代碼如下:

<?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";

}

?>

我們用stream_select()等待sockets打開的連接事件,stream_select()調用系統的select(2)函數來工作,前面三個參數是你要使用的streams的數組,你可以對其讀取,寫入和獲取異常,分別針對三個參數,stream_select()可以通過設置$timeout（秒）參數來等待事件發生-事件發生時,相應的sockets數據將寫入你傳入的參數.

下面是PHP4.1.0之后版本的實現,如果你已經在編譯PHP時包含了sockets(ext/sockets)支持，你可以使用根上面類似的代碼,只是需要將上面的streams/filesystem函數的功能用ext/sockets函數實現,主要的不同在于我們用下面的函數代替stream_socket_client()來建立連接,代碼如下:

<?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;

}

?>

現在用socket_select()替換掉stream_select(),用socket_read()替換掉fread(),用socket_write()替換掉fwrite(),用socket_close()替換掉fclose()就可以執行腳本了.

PHP5的先進之處在于,你可以用stream_select()處理幾乎所有的stream-例如你可以通過include STDIN用它接收鍵盤輸入并保存進數組,你還可以接收通過proc_open()打開的管道中的數據.

下面來分享一個PHP多線程類,代碼如下:

* @title:      PHP多線程類(Thread)

* @version:    1.0

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

* @published:  2010-11-2

*

* PHP多線程應用示例：

*  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']);//開源代碼Vevb.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);

               }

           }

       }

   }