PHP中常用的转义函数_PHP
1. addslashes
addslashes对SQL语句中的特殊字符进行转义操作，包括(‘), (“), (), (NUL)四个字符，此函数在DBMS没有自己的转义函数时候使用，但是如果DBMS有自己的转义函数，那么推荐使用原装函数，比如MySQL有mysql_real_escape_string函数用来转义SQL。 注意在PHP5.3之前，magic_quotes_gpc是默认开启的，其主要是在$GET, $POST, $COOKIE上执行addslashes操作，所以不需要在这些变量上重复调用addslashes，否则会double escaping的。不过magic_quotes_gpc在PHP5.3就已经被废弃，从PHP5.4开始就已经被移除了，如果使用PHP最新版本可以不用担心这个问题。stripslashes为addslashes的unescape函数。
2. htmlspecialchars
htmlspecialchars把HTML中的几个特殊字符转义成HTML Entity(格式：&xxxx;)形式，包括(&),(‘),(“),()五个字符。
& (AND) => &
” (双引号) => " (当ENT_NOQUOTES没有设置的时候)
‘ (单引号) => ' (当ENT_QUOTES设置)
> (大于号) => >
htmlspecialchars可以用来过滤$GET，$POST，$COOKIE数据，预防XSS。注意htmlspecialchars函数只是把认为有安全隐患的HTML字符进行转义，如果想要把HTML所有可以转义的字符都进行转义的话请使用htmlentities。htmlspecialchars_decode为htmlspecialchars的decode函数。
3. htmlentities
htmlentities把HTML中可以转义的内容转义成HTML Entity。html_entity_decode为htmlentities的decode函数。
4. mysql_real_escape_string
mysql_real_escape_string会调用MySQL的库函数mysql_real_escape_string，对(\x00), (\n), (\r), (), (‘), (\x1a)进行转义，即在前面添加反斜杠()，预防SQL注入。注意你不需要在读取数据库数据的时候调用stripslashes来进行unescape，因为这些反斜杠是在数据库执行SQL的时候添加的，当把数据写入到数据库的时候反斜杠会被移除，所以写入到数据库的内容就是原始数据，并不会在前面多了反斜杠。
5. strip_tags
strip_tags会过滤掉NUL，HTML和PHP的标签。
6. 结语
PHP自带的安全函数并不能完全避免XSS，推荐使用HTML Purifier
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
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
Alipay PHP SDK transfer error: How to solve the problem of 'Cannot declare class SignData'?
Apr 01, 2025 am 07:21 AM
Alipay PHP...
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,
How does session hijacking work and how can you mitigate it in PHP?
Apr 06, 2025 am 12:02 AM
Session hijacking can be achieved through the following steps: 1. Obtain the session ID, 2. Use the session ID, 3. Keep the session active. The methods to prevent session hijacking in PHP include: 1. Use the session_regenerate_id() function to regenerate the session ID, 2. Store session data through the database, 3. Ensure that all session data is transmitted through HTTPS.
Describe the SOLID principles and how they apply to PHP development.
Apr 03, 2025 am 12:04 AM
The application of SOLID principle in PHP development includes: 1. Single responsibility principle (SRP): Each class is responsible for only one function. 2. Open and close principle (OCP): Changes are achieved through extension rather than modification. 3. Lisch's Substitution Principle (LSP): Subclasses can replace base classes without affecting program accuracy. 4. Interface isolation principle (ISP): Use fine-grained interfaces to avoid dependencies and unused methods. 5. Dependency inversion principle (DIP): High and low-level modules rely on abstraction and are implemented through dependency injection.
How to debug CLI mode in PHPStorm?
Apr 01, 2025 pm 02:57 PM
How to debug CLI mode in PHPStorm? When developing with PHPStorm, sometimes we need to debug PHP in command line interface (CLI) mode...
What are Enumerations (Enums) in PHP 8.1?
Apr 03, 2025 am 12:05 AM
The enumeration function in PHP8.1 enhances the clarity and type safety of the code by defining named constants. 1) Enumerations can be integers, strings or objects, improving code readability and type safety. 2) Enumeration is based on class and supports object-oriented features such as traversal and reflection. 3) Enumeration can be used for comparison and assignment to ensure type safety. 4) Enumeration supports adding methods to implement complex logic. 5) Strict type checking and error handling can avoid common errors. 6) Enumeration reduces magic value and improves maintainability, but pay attention to performance optimization.
How to automatically set permissions of unixsocket after system restart?
Mar 31, 2025 pm 11:54 PM
How to automatically set the permissions of unixsocket after the system restarts. Every time the system restarts, we need to execute the following command to modify the permissions of unixsocket: sudo...
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.
