Page 14-PHP Tutorial Programming Tutorials: Learn PHP Tutorial Online-php.cn

Article Tags

PHP Tutorial

Home

Technical articles

Backend Development

PHP Tutorial

Explain different error types in PHP (Notice, Warning, Fatal Error, Parse Error).

There are four main error types in PHP: 1.Notice: the slightest, will not interrupt the program, such as accessing undefined variables; 2. Warning: serious than Notice, will not terminate the program, such as containing no files; 3. FatalError: the most serious, will terminate the program, such as calling no function; 4. ParseError: syntax error, will prevent the program from being executed, such as forgetting to add the end tag.

Apr 08, 2025 am 12:03 AM

PHP错误类型PHP错误

Explain strict types (declare(strict_types=1);) in PHP.

Strict types in PHP are enabled by adding declare(strict_types=1); at the top of the file. 1) It forces type checking of function parameters and return values to prevent implicit type conversion. 2) Using strict types can improve the reliability and predictability of the code, reduce bugs, and improve maintainability and readability.

Apr 07, 2025 am 12:05 AM

PHP

How do HTTP Cookies work and what are common security attributes (HttpOnly, Secure, SameSite)?

HTTPCookies works by sending data through the Set-Cookie response header, and the browser automatically appends these cookies in subsequent requests. The security attributes of cookies include: 1.HttpOnly: prevents JavaScript from accessing cookies and reduces the risk of XSS attacks. 2.Secure: Make sure cookies are transmitted only over HTTPS to prevent them from being intercepted. 3.SameSite: Prevent CSRF attacks, and set it to Strict, Lax or None by controlling the sending behavior of cookies in cross-site requests.

Apr 07, 2025 am 12:03 AM

安全属性

What are PHP generators (yield) and what problems do they solve?

Generators and yield keywords in PHP can efficiently process large data sets. 1) The generator is a special function that uses yield to return the value and pauses execution. 2) They generate values step by step, save memory and improve performance. 3) The generator is suitable for scenarios such as large file reading and infinite sequence generation.

Apr 07, 2025 am 12:02 AM

PHP生成器yield关键字

How does PHP handle object comparison (== vs ===)?

In PHP, == compare the attribute value of the object, === compare whether the object is the same instance. 1.==The property values will be compared after type conversion. 2.=== Directly compare the memory address of the object. 3. Custom comparison logic can be implemented through the __equals method.

Apr 07, 2025 am 12:02 AM

对象比较PHP比较运算符

What is Cross-Site Request Forgery (CSRF) and how do you implement CSRF protection in PHP?

In PHP, you can effectively prevent CSRF attacks by using unpredictable tokens. Specific methods include: 1. Generate and embed CSRF tokens in the form; 2. Verify the validity of the token when processing the request.

Apr 07, 2025 am 12:02 AM

PHPcsrf

How would you implement API versioning in PHP?

Implementing API version control in PHP can be achieved through the following steps: 1. Add a version number to the URL, such as /api/v1/users. 2. Use a custom routing mechanism to parse the URL and extract the version number. 3. Call the corresponding processing function according to the version number to ensure the organization and backward compatibility of the code of different versions.

Apr 06, 2025 am 12:09 AM

Describe the purpose and usage of the ... (splat) operator in PHP function arguments and array unpacking.

The... (splat) operator in PHP is used to unpack function parameters and arrays, improving code simplicity and efficiency. 1) Function parameter unpacking: Pass the array element as a parameter to the function. 2) Array unpacking: Unpack an array into another array or as a function parameter.

Apr 06, 2025 am 12:07 AM

PHPsplat运算符

Explain the match expression (PHP 8 ) and how it differs from switch.

In PHP8, match expressions are a new control structure that returns different results based on the value of the expression. 1) It is similar to a switch statement, but returns a value instead of an execution statement block. 2) The match expression is strictly compared (===), which improves security. 3) It avoids possible break omissions in switch statements and enhances the simplicity and readability of the code.

Apr 06, 2025 am 12:03 AM

SwitchPHP

How does session hijacking work and how can you mitigate it in PHP?

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.

Apr 06, 2025 am 12:02 AM

PHP安全会话劫持

Explain Arrow Functions (short closures) introduced in PHP 7.4.

The arrow function was introduced in PHP7.4 and is a simplified form of short closures. 1) They are defined using the => operator, omitting function and use keywords. 2) The arrow function automatically captures the current scope variable without the use keyword. 3) They are often used in callback functions and short calculations to improve code simplicity and readability.

Apr 06, 2025 am 12:01 AM

箭头函数PHP 7.4

Explain the concept of Dependency Injection (DI) in PHP.

The core value of using dependency injection (DI) in PHP lies in the implementation of a loosely coupled system architecture. DI reduces direct dependencies between classes by providing dependencies externally, improving code testability and flexibility. When using DI, you can inject dependencies through constructors, set-point methods, or interfaces, and manage object lifecycles and dependencies in combination with IoC containers.

Apr 05, 2025 am 12:07 AM

依赖注入PHP依赖注入

What is the difference between include, require, include_once, require_once?

In PHP, the difference between include, require, include_once, require_once is: 1) include generates a warning and continues to execute, 2) require generates a fatal error and stops execution, 3) include_once and require_once prevent repeated inclusions. The choice of these functions depends on the importance of the file and whether it is necessary to prevent duplicate inclusion. Rational use can improve the readability and maintainability of the code.

Apr 05, 2025 am 12:07 AM

Explain HTTP status codes (2xx, 3xx, 4xx, 5xx). Give examples.

HTTP status codes are divided into four categories: 2xx means the request is successful, 3xx means redirection is required, 4xx means client error, and 5xx means server error. 2xx status code such as 200OK means the request is successful, 201Created means the resource creation is successful; 3xx status code such as 301MovedPermanently means permanent redirection, 302Found means temporary redirection; 4xx status code such as 404NotFound means the resource is not found, 400BadRequest means the request syntax error; 5xx status code such as 500InternalServerError means the server internal error, 503ServiceUnavailabl

Apr 05, 2025 am 12:06 AM

错误代码HTTP状态码