PHP common server and environment function libraries

PHP is a widely used server-side scripting language that plays an important role in web development. In the development process of PHP, server and environment function libraries play a very important role in order to allow developers to better write efficient and reliable PHP scripts. The following are commonly used server and environment function libraries for PHP.

1. Server function library

1. $_SERVER

$_SERVER is one of the commonly used server variables in PHP. It provides information about the current script running environment. Information. It contains an array of server and request variables, including HTTP header information, path and script location, etc.

2. $_GET

$_GET is a super global variable that transfers data from the URL to the PHP script. It obtains the data through the key-value pair in the URL. This is very common in developing WEB applications. It is equivalent to a GET request and is often used to query resources from the server. $_GET can pass data from HTML forms, JavaScript, or URL inputs to server-side scripts.

3. $_POST

$_POST is another common super global variable in PHP. It is usually used to POST data from the client in HTML forms. to the server side. POST requests are more secure than GET requests because the data passed will not be included in the URL.

4. $_FILES

$_FILES is used to process files uploaded from the client. It stores the corresponding information of the uploaded file (such as size, type, etc.) as an array and copies it to a temporary directory on the server for further processing.

5. header()

The header() function sends the original HTTP header in the HTTP response. It cooperates with other server and environment function libraries and can be used to control caching, redirection, or send some status codes to the client, etc.

2. Environment function library

1. $_ENV

$_ENV is a super global variable in PHP, which is used to handle issues related to the operating system or Environment variables for the web server. Any process in the operating system has a copy of its environment variables, and PHP accesses this copy environment through $_ENV to obtain its contents.

2. getenv()

The getenv() function gets the value of an environment variable by name. It can read environment variables in any operating system and return them as strings.

3. putenv()

putenv() function is a function that sets environment variables. It accepts one parameter, which should be in the form of a string representing the name and value of the environment variable. function adds it to the list of environment variables for the currently running script.

4. date_default_timezone_set()

The date_default_timezone_set() function was added after the PHP5.1 version. It is used to set the time zone where the script is located. If not set, the date and time may be inaccurate due to the computer's own default time zone settings.

5. ini_set()

The ini_set() function is used to set the options of the PHP configuration file. Through this function, developers can set and modify PHP configuration parameters, such as setting memory limits, upload file size, etc.

Summary:

Server and environment function libraries are a very important part of PHP, and they play an extremely important role in the development process. Server function libraries include $_SERVER, $_GET and $_POST, etc., which are used to obtain relevant information requested by the Web server or user. The environment function library includes $_ENV, getenv() and putenv(), etc., which are used to obtain and manage information about the current PHP running environment. By learning these function libraries, developers can write PHP scripts more efficiently and bring more convenience to web development.

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