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本文介绍了PHP学习:php多线程实现方法及用法实例详解,希望对您有用。如果有疑问,可以联系我们。
PHP实战下面我们来介绍具体php多线程实现程序代码,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:
代码如下
PHP实战
<?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);
?>
PHP实战它运行的很好,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.
有两种办法可以实现: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中的解决办法:
代码如下
PHP实战
<?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";
}
?>
PHP实战我们用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$timeout(秒)参数来等待事件发生-事件发生时,相应的sockets数据将写入你传入的参数.
下面是PHP4.1.0之后版本的实现,如果你已经在编译PHP时包含了sockets(ext/sockets)支持,你可以使用根上面类似的代码,只是需要将上面的streams/filesystem函数的功能用ext/sockets函数实现.主要的不同在于我们用下面的函数代替stream_socket_client()来建立连接:
代码如下
PHP实战
<?php
// This value is correct for Linux, other systems have other values
define('EINPROGRESS', 115);
function non_blocking_connect($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;
}
?>
PHP实战现在用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
PHP实战
* @title: PHP多线程类(Thread)
* @version: 1.0
*
* 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);
* }
*/
class 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'],$_SERVER['SERVER_PORT']);
if($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);
}
}
}
}
}
PHP实战希望本文所述对大家的PHP程序设计有所赞助.
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