Method of using locking to implement code grabbing function under concurrency based on PHP-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

Method of using locking to implement code grabbing function under concurrency based on PHP

墨辰丷

Jun 01, 2018 pm 03:44 PM

php accomplish concurrent

This article is based on the PHP language and uses locking to implement the code grabbing function under concurrent conditions. The code grabbing is open during a specific period of time and does not allow the open codes to be repeated. The introduction in this article is very detailed. Friends who need it can refer to the

Requirements : Code grabbing function

Requirements:

1. Code grabbing is only open during a specific time period;

2.The codes released in each time period are limited;

3. Each code is not allowed to be repeated;

Implementation:

1. Implementation without considering concurrency:

function get_code($len){
$CHAR_ARR = array(&#39;1&#39;,&#39;2&#39;,&#39;3&#39;,&#39;4&#39;,&#39;5&#39;,&#39;6&#39;,&#39;7&#39;,&#39;8&#39;,&#39;9&#39;,&#39;A&#39;,&#39;B&#39;,&#39;C&#39;,&#39;D&#39;,&#39;E&#39;,&#39;F&#39;,&#39;G&#39;,&#39;H&#39;,&#39;I&#39;,&#39;J&#39;,&#39;K&#39;,&#39;L&#39;,&#39;M&#39;,&#39;N&#39;,&#39;O&#39;,&#39;P&#39;,&#39;Q&#39;,&#39;X&#39;,&#39;Y&#39;,&#39;Z&#39;,&#39;W&#39;,&#39;S&#39;,&#39;R&#39;,&#39;T&#39;);
$CHAR_ARR_LEN = count($CHAR_ARR) - 1;
$code = &#39;&#39;;
while(--$len > 0){ $code .= $CHAR_ARR[rand(0,$CHAR_ARR_LEN)]; }
return $code;
}
$pdo = new PDO(&#39;mysql:host=localhost;dbname=ci_test&#39;,&#39;root&#39;,&#39;root&#39;);
//查询当前时间已发放验证码数量
$code_num_rs = $pdo->query("SELECT COUNT(*) as sum FROM code_test");
$code_num_arr = $code_num_rs->fetch(PDO::FETCH_ASSOC);
$code_num = $code_num_arr[&#39;sum&#39;];
if($code_num < 1){<br>　　 sleep(2); //暂停2秒
$code = get_code(6);
var_dump( $pdo->query("INSERT INTO code_test (code,create_time) VALUES (&#39;$code&#39;,".time().")") );
}

Copy after login

The above code satisfies the current situation by default is the opening time, and the codes are not repeated;

Process without considering concurrency:

1) Select to query the number of verification codes issued by the current database;

2 ) If there are still places, generate a verification code, insert it into the database, and return the verification code to the client;

　3) If it is full; then return a prompt that there are no places;

2, Implemented under concurrent conditions:

Then take a look at the results obtained by the above code under concurrent conditions:

To test concurrency, you can use apache benchmark to test. apache benchmark is the performance of the HTTP SERVER under APACHE. For the evaluation tool, enter the bin directory of apche through cmd and call it through the ab command, such as: ab -c concurrent number -n total visits url

The code is as follows:

cb -c 100 -n 100 http://localhost/php_mulit.php

In this way, 100 users and colleagues compete for 1 quota. When querying, each user finds that there is still one quota, then It will generate a verification code, insert it into the database, and return the verification code; this will cause too many verification codes to be sent. In fact, after running this command, the database has 13 more records instead of one.

How to avoid this happening?

You can lock the process from judgment to insertion by adding an exclusive lock to ensure that only one process is running in this judgment process at any time. The implementation is as follows:

//生成码
function get_code($len){
$CHAR_ARR = array(&#39;1&#39;,&#39;2&#39;,&#39;3&#39;,&#39;4&#39;,&#39;5&#39;,&#39;6&#39;,&#39;7&#39;,&#39;8&#39;,&#39;9&#39;,&#39;A&#39;,&#39;B&#39;,&#39;C&#39;,&#39;D&#39;,&#39;E&#39;,&#39;F&#39;,&#39;G&#39;,&#39;H&#39;,&#39;I&#39;,&#39;J&#39;,&#39;K&#39;,&#39;L&#39;,&#39;M&#39;,&#39;N&#39;,&#39;O&#39;,&#39;P&#39;,&#39;Q&#39;,&#39;X&#39;,&#39;Y&#39;,&#39;Z&#39;,&#39;W&#39;,&#39;S&#39;,&#39;R&#39;,&#39;T&#39;);
$CHAR_ARR_LEN = count($CHAR_ARR) - 1;
$code = &#39;&#39;;
while(--$len > 0){ $code .= $CHAR_ARR[rand(0,$CHAR_ARR_LEN)]; }
return $code;
}
$pdo = new PDO(&#39;mysql:host=localhost;dbname=ci_test&#39;,&#39;root&#39;,&#39;root&#39;);
$fp = fopen(&#39;lock.txt&#39;,&#39;r&#39;);
//通过排他锁 锁定该过程
if(flock($fp,LOCK_EX)){
//查询当前时间已发放验证码数量
$code_num_rs = $pdo->query("SELECT COUNT(*) as sum FROM code_test");
$code_num_arr = $code_num_rs->fetch(PDO::FETCH_ASSOC);
$code_num = $code_num_arr[&#39;sum&#39;];
if($code_num < 1){
sleep(2);
$code = get_code(6);
var_dump( $pdo->query("INSERT INTO code_test (code,create_time) VALUES (&#39;$code&#39;,".time().")") );
}
flock($fp,LOCK_UN);
fclose($fp);
}

Copy after login

Lock the process through flock function.

For more flock information, please refer to the php manual: http://php.net/manual/zh/function.flock.php

Run again

The code is as follows:

cb -c 100 -n 100 http://localhost/php_mulit.php

Only one record is added to the database, ensuring that the data is correct under concurrent conditions.

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

Related recommendations:

php Detailed examples of the difference between die() and exit()

# #phpmailer implements the method of binding mailbox

phpUsage of image processing function imagecopyresampled

The above is the detailed content of Method of using locking to implement code grabbing function under concurrency based on PHP. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

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

How to fix KB5055612 fails to install in Windows 10?

3 weeks ago By DDD

Roblox: Grow A Garden - Complete Mutation Guide

3 weeks ago By DDD

Roblox: Bubble Gum Simulator Infinity - How To Get And Use Royal Keys

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Mandragora: Whispers Of The Witch Tree - How To Unlock The Grappling Hook

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Nordhold: Fusion System, Explained

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial

1668

CakePHP Tutorial

1427

Laravel Tutorial

1329

PHP Tutorial

1273

C# Tutorial

1256

Related knowledge

PHP: A Key Language for Web Development Apr 13, 2025 am 12:08 AM

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

PHP and Python: Comparing Two Popular Programming Languages Apr 14, 2025 am 12:13 AM

PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.

PHP vs. Python: Understanding the Differences Apr 11, 2025 am 12:15 AM

PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.

PHP in Action: Real-World Examples and Applications Apr 14, 2025 am 12:19 AM

PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.

The Enduring Relevance of PHP: Is It Still Alive? Apr 14, 2025 am 12:12 AM

PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.

PHP vs. Other Languages: A Comparison Apr 13, 2025 am 12:19 AM

PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.

PHP and Python: Different Paradigms Explained Apr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: Code Examples and Comparison Apr 15, 2025 am 12:07 AM

PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.

See all articles