Home Backend Development PHP Tutorial PHP uses addslashes function to implement SQL injection prevention example explanation

PHP uses addslashes function to implement SQL injection prevention example explanation

May 22, 2017 pm 12:00 PM

We know that the addslashes() function adds a backslash before certain predefined characters in the input string. So how does it relate to our anti-sql injection? What is sql injection?

SQL injection attacks are the most common means used by hackers to attack websites. If your site does not use strict user input validation, it is often vulnerable to SQL injection attacks. SQL injection attacks are usually implemented by submitting bad data or query statements to the site database

, which may cause records in the database to be exposed, changed or deleted. This articlemainly introducesphp uses addslashes function to implement sql anti-injection example explanation,pass The example describes the use of addslashes function to prevent SQL injection.

Example

The parameter 'a..z' defines that all uppercase and lowercase letters are escaped, the code is as follows:

echo addcslashes('foo[ ]','a..z'); //输出:foo[ ] 
$str="is your name o'reilly?"; //定义字符串,其中包括需要转义的字符 
echo addslashes($str);  //输出经过转义的字符串
Copy after login

Definition And usage:

addslashes() function adds a backslash before the specified predefined characters.

These predefined characters are: single quotation mark ('), double quotation mark ("), reverse Slash(),null

Syntax:

addslashes(string)
Copy after login

Of course this function is safer, the example code is as follows:

$str="<a href=&#39;test&#39;>test</a>"; //定义包含特殊字符的字符串 
$new=htmlspecialchars($str,ent_quotes);  //进行转换操作 
echo $new;           //输出转换结果 
//不过输出时要用到 
$str="jane & &#39;tarzan&#39;";  //定义html字符串 
echo html_entity_decode($str);   //输出转换后的内容 
echo "<br/>"; 
echo html_entity_decode($str,ent_quotes); //有可选参数输出的内容
Copy after login

This article is good for PHP security program design Reference value. However, there are ways to circumvent using addslashes to prevent SQL injection hackers, and it is not that safe. Many PHP programmers still rely on addslashes to prevent SQL injection.

## Enter, it is recommended that you strengthen the check to prevent SQL injection in Chinese. The problem with addslashes is that hackers can use 0xbf27 to replace single quotes, while addslashes only changes 0xbf27 to 0xbf5c27, which becomes a valid multi-byte character.

The 0xbf5c is still regarded as a single quote, so addslashes cannot successfully intercept it. Of course, addslashes is not useless, it is used for single words. Processing of section strings

[Recommended related articles]:

1.

php addslashes() function and stripslashes() function examples detailed explanation

2.

Detailed examples of the difference between php stripslashes() function and addslashes() function

The above is the detailed content of PHP uses addslashes function to implement SQL injection prevention example explanation. 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

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1664
14
PHP Tutorial
1268
29
C# Tutorial
1246
24
Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Apr 05, 2025 am 12:04 AM

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

PHP Program to Count Vowels in a String PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

Explain late static binding in PHP (static::). Explain late static binding in PHP (static::). Apr 03, 2025 am 12:04 AM

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? Apr 03, 2025 am 12:03 AM

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.

PHP and Python: Comparing Two Popular Programming Languages 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 in Action: Real-World Examples and Applications 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.

PHP: A Key Language for Web Development 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

The Enduring Relevance of PHP: Is It Still Alive? 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.

See all articles