最近在做一个需要用到异步
PHP的项目, 翻阅PHP
源码的时候,发现了三个没有用过的模块,sysvsem,sysvshm,sysvmsg,一番研究以后,受益非浅。
在PHP中有这么一族
函数,他们是对UNIX的V IPC函数族的包装。
它们很少被人们用到,但是它们却很强大。巧妙的运用它们,可以让你事倍功半。
它们包括:
- 信号量(Semaphores)
- 共享内存(Shared Memory)
- 进程间通信(Inter-Process Messaging, IPC)
基于这些,我们完全有可能将PHP包装成一基于消息驱动的
系统。
但是,首先,我们需要介绍几个重要的基础:
1. ftok
int ftok ( string pathname,
string proj )![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
//ftok将一个路径名pathname和一个项目名(必须为一个字符), 转化成一个整形的用来使用系统V IPC的key![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
2. ticks
Ticks是从PHP 4.0.3开始才加入到PHP中的,它是一个在declare
代码段中解释器每执行N条低级语句就会发生的事件。N的值是在declare中的directive部分用ticks=N来指定的。
function getStatus($arg){
print_r
connection_status();
debug_print_backtrace();
}
reigster_tick_function(
“getStatus“,
true);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
declare(ticks=1){
for($i
=1; $i<999; $i++){
echo
“hello“;
}
}
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
unregister_tick_function(“getStatus“);
这个就基本相当于:
function getStatus($arg){
print_r
connection_status();
debug_print_backtrace();
}
reigster_tick_function(
“getStatus“,
true);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
declare(ticks=1){
for($i
=1; $i<999; $i++){
echo
“hello“; getStatus(true);
}
}
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
unregister_tick_function(“getStatus“);
消息,我现在用一个例子来说明,如何结合Ticks来实现PHP的消息通信。
$mesg_key
= ftok(__FILE__,
‘m‘);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$mesg_id
= msg_get_queue($mesg_key,
0666);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
function fetchMessage($mesg_id){
if(!is_resource($mesg_id)){
print_r(“Mesg Queue is not Ready“);
}
if(msg_receive($mesg_id,
0,
$mesg_type,
1024,
$mesg,
false, MSG_IPC_NOWAIT)){
print_r(“Process got a new incoming MSG: $mesg “);
}
}
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
register_tick_function(“fetchMessage“,
$mesg_id);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
declare(ticks=2){
$i
=
0;
while(++$i
<
100){
if($i%5
==
0){
msg_send(
$mesg_id,
1,
“Hi: Now Index is :“.
$i);
}
}
}
//msg_remove_queue(
$mesg_id);
在这个例子中,首先将我们的PHP执行Process加入到一个由ftok生成的Key所获得的消息队列中。
然后,通过Ticks,没隔俩个语句,就去
查询一次消息队列。
然后模拟了消息发送。
在浏览器访问这个脚本,结果如下:
Process got a new incoming MSG: s:19:”Hi: Now Index is :5″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :10″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :15″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :20″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :25″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :30″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :35″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :40″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :45″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :50″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :55″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :60″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :65″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :70″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :75″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :80″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :85″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :90″;
Process got a new incoming MSG: s:20:”Hi: Now Index is :95″;
看到这里是不是,大家已经对怎么模拟PHP为事件驱动已经有了一个概念了? 别急,我们继续完善。
2. 信号量
信号量的概念,大家应该都很熟悉。通过信号量,可以实现进程通信,竞争等。 再次就不赘述了,只是简单的列出PHP中提供的信号量函数集。
sem_acquire – Acquire a semaphore
sem_get
– Get a semaphore id
sem_release
– Release a semaphore
sem_remove
– Remove a semaphore
具体信息,可以翻阅PHP手册。
3. 内存共享
PHP sysvshm提供了一个内存共享方案:sysvshm,它是和sysvsem,sysvmsg一个系列的,但在此处,我并没有使用它,我使用的shmop系列函数,结合TIcks
function memoryUsage(){
printf(“%s: %s
“,
date(“H:i:s“,
$now), memory_get_usage());
//var_dump(debug_backtrace());
//var_dump(__FUNCTION__);
//debug_print_backtrace();
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
}![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
register_tick_function(“memoryUsage“);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
declare(ticks=1){![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$shm_key
= ftok(__FILE__,
‘s‘);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$shm_id
= shmop_open($shm_key,
‘c‘,
0644,
100);
}
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
printf(“Size of Shared Memory is: %s
“, shmop_size($shm_id));![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$shm_text
= shmop_read($shm_id,
0,
100);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
eval($shm_text);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
if(!empty($share_array)){
var_dump($share_array);
$share_array['id'] +=
1;![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
}
else{
$share_array
=
array(‘id‘
=>
1);
}
![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$out_put_str
=
“$share_array = “
.
var_export($share_array,
true) .“;“;![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
$out_put_str
=
str_pad($out_put_str,
100,
“
“, STR_PAD_RIGHT);
shmop_write(
$shm_id,
$out_put_str,
0);![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
?>![](http://images.csdn.net/syntaxhighlighting/OutliningIndicators/None.gif)
运行这个例子,不断刷新,我们可以看到index在递增。
单单使用这个shmop就能完成一下,PHP脚本之间共享
数据的
功能:以及,比如缓存,计数等等。
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