Detailed explanation of PHP multi-process programming examples
This article mainly introduces the PHP multi-process programming method to you. It analyzes the concept, usage, related functions and usage skills of PHP multi-process programming in more detail. Friends in need can refer to it. I hope it can help everyone.
The details are as follows:
Step one:
$ php -m command checks whether php has pcntl and posix extensions installed, if not, install them
Usage scenarios:
1. A large number of time-consuming network operations are required
2. A large number of operations are required, and the system has multiple CPUs. In order to give users a faster experience, divide a task into several small tasks and finally merge them.
Commonly used functions for multiple processes:
pcntl_alarm — Set an alarm clock signal for the process
pcntl_errno — Alias pcntl_strerror
pcntl_exec —Execute the specified program in the current process space
pcntl_fork—Create a child process and generate a branch (child process) at the current position of the current process. Annotation: fork creates a child process. Both the parent process and the child process continue to execute from the fork position. The difference is that during the execution of the parent process, the return value of fork is the child process number, while the child process gets 0.
pcntl_get_last_error — Retrieve the error number set by the last pcntl function which failed
pcntl_getpriority — Get the priority of any process
pcntl_setpriority — Modify the priority of any process
pcntl_signal_dispatch — Call a handler waiting for a signal
pcntl_signal — Install a signal handler
pcntl_sigprocmask — Set or retrieve blocking signals
pcntl_sigtimedwait — Signal waiting with timeout mechanism
pcntl_sigwaitinfo — Wait for signals
pcntl_strerror — Retrieve the system error message associated with the given errno
pcntl_wait — Wait for or return the child process status of fork
pcntl_waitpid — Wait for or return the child process status of fork
pcntl_wexitstatus — Returns the return code of an interrupted child process
pcntl_wifexited — Checks whether the status code represents a normal exit.
pcntl_wifsignaled — Check whether the child process status code represents an interruption due to a signal
pcntl_wifstopped — Check whether the child process is currently stopped
pcntl_wstopsig — Return the signal that causes the child process to stop
pcntl_wtermsig — Return the signal that causes the child process to interrupt
Example 1:
<?php //最早的进程,也是父进程 $parentPid = getmypid(); echo '原始父进程:' . $parentPid . PHP_EOL; //创建子进程,返回子进程id $pid = pcntl_fork(); if( $pid == -1 ){ exit("fork error"); } //pcntl_fork 后,父进程返回子进程id,子进程返回0 echo 'ID : ' . $pid . PHP_EOL; if( $pid == 0 ){ //子进程执行pcntl_fork的时候,pid总是0,并且不会再fork出新的进程 $mypid = getmypid(); // 用getmypid()函数获取当前进程的PID echo 'I am child process. My PID is ' . $mypid . ' and my fathers PID is ' . $parentPid . PHP_EOL; } else { //父进程fork之后,返回的就是子进程的pid号,pid不为0 echo 'Oh my god! I am a father now! My childs PID is ' . $pid . ' and mine is ' . $parentPid . PHP_EOL; } $aa = shell_exec("ps -af | grep index.php"); echo $aa;
Example 2: Open multiple child processes to avoid fork flooding
<?php //最早的进程,也是父进程 $parentPid = getmypid(); echo '原始父进程:' . $parentPid . PHP_EOL; //开启十个子进程 for($i = 0; $i < 10; $i++) { $pid = pcntl_fork(); if($pid == -1) { echo "Could not fork!\n"; exit(1); } //子进程 if(!$pid) { //child process workspace echo '子进程:' . getmypid() . PHP_EOL; exit(); //子进程逻辑执行完后,马上退出,以免往下走再fork子进程,不好控制 } else { echo '父进程:' . getmypid() . PHP_EOL; } } echo getmypid() . PHP_EOL; $aa = shell_exec("ps -af | grep index.php"); echo $aa;
Related recommendations:
Code cases about multi-process programming in php
PHP server-side multi-process programming practice_PHP tutorial
PHP multi-process Programming example description
The above is the detailed content of Detailed explanation of PHP multi-process programming examples. For more information, please follow other related articles on the PHP Chinese website!

Effective methods to prevent session fixed attacks include: 1. Regenerate the session ID after the user logs in; 2. Use a secure session ID generation algorithm; 3. Implement the session timeout mechanism; 4. Encrypt session data using HTTPS. These measures can ensure that the application is indestructible when facing session fixed attacks.

Implementing session-free authentication can be achieved by using JSONWebTokens (JWT), a token-based authentication system where all necessary information is stored in the token without server-side session storage. 1) Use JWT to generate and verify tokens, 2) Ensure that HTTPS is used to prevent tokens from being intercepted, 3) Securely store tokens on the client side, 4) Verify tokens on the server side to prevent tampering, 5) Implement token revocation mechanisms, such as using short-term access tokens and long-term refresh tokens.

The security risks of PHP sessions mainly include session hijacking, session fixation, session prediction and session poisoning. 1. Session hijacking can be prevented by using HTTPS and protecting cookies. 2. Session fixation can be avoided by regenerating the session ID before the user logs in. 3. Session prediction needs to ensure the randomness and unpredictability of session IDs. 4. Session poisoning can be prevented by verifying and filtering session data.

To destroy a PHP session, you need to start the session first, then clear the data and destroy the session file. 1. Use session_start() to start the session. 2. Use session_unset() to clear the session data. 3. Finally, use session_destroy() to destroy the session file to ensure data security and resource release.

How to change the default session saving path of PHP? It can be achieved through the following steps: use session_save_path('/var/www/sessions');session_start(); in PHP scripts to set the session saving path. Set session.save_path="/var/www/sessions" in the php.ini file to change the session saving path globally. Use Memcached or Redis to store session data, such as ini_set('session.save_handler','memcached'); ini_set(

TomodifydatainaPHPsession,startthesessionwithsession_start(),thenuse$_SESSIONtoset,modify,orremovevariables.1)Startthesession.2)Setormodifysessionvariablesusing$_SESSION.3)Removevariableswithunset().4)Clearallvariableswithsession_unset().5)Destroythe

Arrays can be stored in PHP sessions. 1. Start the session and use session_start(). 2. Create an array and store it in $_SESSION. 3. Retrieve the array through $_SESSION. 4. Optimize session data to improve performance.

PHP session garbage collection is triggered through a probability mechanism to clean up expired session data. 1) Set the trigger probability and session life cycle in the configuration file; 2) You can use cron tasks to optimize high-load applications; 3) You need to balance the garbage collection frequency and performance to avoid data loss.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 English version
Recommended: Win version, supports code prompts!

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SublimeText3 Chinese version
Chinese version, very easy to use

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
