PHP在很多时候不适合做常驻的SHELL进程,他没有专门的gc例程,也没有有效的内存管理途径. 所以如果用PHP做常驻SHELL,你会经常被内存耗尽导致abort而unhappy. 而且,如果输入数据非法,而脚本没有检测,导致abort,也会让你很不开心. 那? 怎么办呢? 多进程…. 为什么呢?
优点:
1. 使用多进程,子进程结束以后,内核会负责回收资源 2. 使用多进程,子进程异常退出不会导致整个进程Thread退出. 父进程还有机会重建流程.
3. 一个常驻主进程,只负责任务分发,逻辑更清楚 Then,怎么做呢? 接下来,我们使用PHP提供的POSIX和Pcntl系列函数,来实现一个PHP命令解析器,主进程负责接受用户输入,然后fork子进程执行,并负责回显子进程的结束状态. 代码如下,我加了注释,如果有不懂的地方,可以翻阅手册相关函数,或者回复留言.
代码如下:
#!/bin/env PHP
PHP
/** A example denoted muti-process application in PHP
* @filename fork.PHP
* @touch date Wed 10 Jun 2009 10:25:51 PM CST
* @author Laruence
* @license http://www.zend.com/license/3_0.txt PHP License 3.0
* @version 1.0.0
*/ /** 确保这个函数只能运行在SHELL中 */
if (substr(PHP_sapi_name(),3) !== 'cli') {
die("This Programe can only be run in CLI mode");
} /** 关闭最大执行时间限制,在CLI模式下,这个语句其实不必要 */
set_time_limit(0); $pid = posix_getpid(); //取得主进程ID
$user = posix_getlogin(); //取得用户名 echo <<USAGE: [command | expression]
input PHP code to execute by fork a new process
input quit to exit Shell Executor version 1.0.0 by laruence
EOD; while (true) { $prompt = "\n{$user}$ ";
$input = readline($prompt); readline_add_history($input);
if ($input == 'quit') {
break;
}
process_execute($input . ';');
} exit(0); function process_execute($input) {
$pid = pcntl_fork(); //创建子进程
if ($pid == 0) {//子进程
$pid = posix_getpid();
echo "* Process {$pid} was created,and Executed:\n\n";
eval($input); //解析命令
exit;
} else {//主进程
$pid = pcntl_wait($status,WUNTRACED); //取得子进程结束状态
if (pcntl_wifexited($status)) {
echo "\n\n* Sub process: {$pid} exited with {$status}";
}
}
}
PHP
/** A example denoted muti-process application in PHP
* @filename fork.PHP
* @touch date Wed 10 Jun 2009 10:25:51 PM CST
* @author Laruence
* @license http://www.zend.com/license/3_0.txt PHP License 3.0
* @version 1.0.0
*/ /** 确保这个函数只能运行在SHELL中 */
if (substr(PHP_sapi_name(),3) !== 'cli') {
die("This Programe can only be run in CLI mode");
} /** 关闭最大执行时间限制,在CLI模式下,这个语句其实不必要 */
set_time_limit(0); $pid = posix_getpid(); //取得主进程ID
$user = posix_getlogin(); //取得用户名 echo <<
input PHP code to execute by fork a new process
input quit to exit Shell Executor version 1.0.0 by laruence
EOD; while (true) { $prompt = "\n{$user}$ ";
$input = readline($prompt); readline_add_history($input);
if ($input == 'quit') {
break;
}
process_execute($input . ';');
} exit(0); function process_execute($input) {
$pid = pcntl_fork(); //创建子进程
if ($pid == 0) {//子进程
$pid = posix_getpid();
echo "* Process {$pid} was created,and Executed:\n\n";
eval($input); //解析命令
exit;
} else {//主进程
$pid = pcntl_wait($status,WUNTRACED); //取得子进程结束状态
if (pcntl_wifexited($status)) {
echo "\n\n* Sub process: {$pid} exited with {$status}";
}
}
}
但有一点,我一定要提醒:
代码如下:
原文：http://www.laruence.com/2009/06/11/930.html