PHP多线程的实现方法详解
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测试数据" , "host2.sample测试数据" , "host3.sample测试数据" ); $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测试数据" , "host2.sample测试数据" , "host3.sample测试数据" ); $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测试数据 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 ); } } } }查看更多关于PHP多线程的实现方法详解 - php高级应用的详细内容...
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