【PHP 一些专业词汇+概念解释】
PHP 弱类型语言，大小写敏感，脚本语言（解释性，文本文件执行），服务端。
OOP [Object Oriented Programming]
SAPI [Server Application Programming Interface ]
link
服务器端应用编程端口。它就是PHP与其它应用交互的接口，PHP脚本要执行有很多种方式，通过Web服务器，或者直接在命令行下，也可以嵌入在其他程序中。
SAPI提供了一个和外部通信的接口，常见的SAPI有：cgi 、fast-cgi、cli、isapi、apache 模块的 DLL
CGI
CGI即通用网关接口(Common Gateway Interface)，它是一段程序，通俗的讲CGI就象是一座桥，把网页和WEB服务器中的执行程序连接起来，它把HTML接收的指令传递给服务器的执 行程序，再把服务器执行程序的结果返还给HTML页。CGI 的跨平台性能极佳，几乎可以在任何操作系统上实现。
CGI方式在遇到连接请求（用户 请求）先要创建cgi的子进程，激活一个CGI进程，然后处理请求，处理完后结束这个子进程。这就是fork-and-execute模式。所以用cgi 方式的服务器有多少连接请求就会有多少cgi子进程，子进程反复加载是cgi性能低下的主要原因。都会当用户请求数量非常多时，会大量挤占系统的资源如内 存，CPU时间等，造成效能低下。
FastCGI
fast-cgi 是cgi的升级版本，FastCGI像是一个常驻(long-live)型的CGI，它可以一直执行着，只要激活后，不会每次都要花费时间去fork一 次。PHP使用PHP-FPM(FastCGI Process Manager)，全称PHP FastCGI进程管理器进行管理。
FastCGI的工作原理
Web Server启动时载入FastCGI进程管理器(IIS ISAPI或Apache Module)
FastCGI进程管理器自身初始化，启动多个CGI解释器进程(可见多个php-cgi)并等待来自Web Server的连接。
当客户端请求到达Web Server时，FastCGI进程管理器选择并连接到一个CGI解释器。Web server将CGI环境变量和标准输入发送到FastCGI子进程php-cgi。
FastCGI子进程完成处理后将标准输出和错误信息从同一连接返回Web Server。当FastCGI子进程关闭连接时，请求便告处理完成。FastCGI子进程接着等待并处理来自FastCGI进程管理器(运行在Web Server中)的下一个连接。 在CGI模式中，php-cgi在此便退出了。
在上述情况中，你可以想象CGI通常有多慢。每一个Web 请求PHP都必须重新解析php.ini、重新载入全部扩展并重初始化全部数据结构。使用FastCGI，所有这些都只在进程启动时发生一次。一个额外的 好处是，持续数据库连接(Persistent database connection)可以工作。
APACHE2HANDLER
PHP作为Apache模块，Apache服务器在系统启动后，预先生成多个进程副本驻留在内存中，一旦有请求出 现，就立即使用这些空余的子进程进行处理，这样就不存在生成子进程造成的延迟了。这些服务器副本在处理完一次HTTP请求之后并不立即退出，而是停留在计 算机中等待下次请求。对于客户浏览器的请求反应更快，性能较高。
apache模块的DLL：
该运行模式是我们以前在windows环境下使用apache服务器经常使用的，而在模块化(DLL)中，PHP是与Web服务器一起启动并运行的。（是apache在CGI的基础上进行的一种扩展，加快PHP的运行效率）
ISAPI:
ISAPI即Internet Server Application Program Interface，是微软提供的一套面向Internet服务的API接口.一个ISAPI的DLL，可以在被用户请求激活后长驻内存，等待用户的另一个请求，还可以在一个DLL里设置多个用户请求处理函数，此外，ISAPI的DLL应用程序和WWW服务器处于同一个进程中，效率要显著高于CGI。
cli:[php CLI模式介绍]
cli是php的命令行运行模式，大家经常会使用它，但是可能并没有注意到（例如：我们在linux下经常使用 “php -m”查找PHP安装了那些扩展就是PHP命令行运行模式；
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
1655
14
1413
52
1306
25
1252
29
1226
24
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.
What is REST API design principles?
Apr 04, 2025 am 12:01 AM
RESTAPI design principles include resource definition, URI design, HTTP method usage, status code usage, version control, and HATEOAS. 1. Resources should be represented by nouns and maintained at a hierarchy. 2. HTTP methods should conform to their semantics, such as GET is used to obtain resources. 3. The status code should be used correctly, such as 404 means that the resource does not exist. 4. Version control can be implemented through URI or header. 5. HATEOAS boots client operations through links in response.
How do you handle exceptions effectively in PHP (try, catch, finally, throw)?
Apr 05, 2025 am 12:03 AM
In PHP, exception handling is achieved through the try, catch, finally, and throw keywords. 1) The try block surrounds the code that may throw exceptions; 2) The catch block handles exceptions; 3) Finally block ensures that the code is always executed; 4) throw is used to manually throw exceptions. These mechanisms help improve the robustness and maintainability of your code.
What are anonymous classes in PHP and when might you use them?
Apr 04, 2025 am 12:02 AM
The main function of anonymous classes in PHP is to create one-time objects. 1. Anonymous classes allow classes without names to be directly defined in the code, which is suitable for temporary requirements. 2. They can inherit classes or implement interfaces to increase flexibility. 3. Pay attention to performance and code readability when using it, and avoid repeatedly defining the same anonymous classes.
What is the difference between include, require, include_once, require_once?
Apr 05, 2025 am 12:07 AM
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.
Explain different error types in PHP (Notice, Warning, Fatal Error, Parse Error).
Apr 08, 2025 am 12:03 AM
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.
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.
