How to use require in php

require function is used in PHP to include an external file and, after checking, insert the file contents into the current script. It is similar to the include function, but require triggers a fatal error if the file does not exist, while include only issues a warning. Best practices include ensuring file paths are correct, using absolute paths, and avoiding nested references.

Usage of require in PHP

require is a function in PHP used to include external files. It starts from the specified The path to the file is loaded and its contents are inserted into the current script.

Usage

<code class="php">require '/path/to/file.php';</code>

Parameters

• ##/path/to/file.php : The path to the file to include.

How it works

require first checks the specified path and if the file exists, it loads the contents of the file and inserts it into the current script. If the file does not exist, it triggers a fatal error, causing the script to terminate.

Uses

require is typically used to contain functions, classes, or other commonly used blocks of code for reuse in multiple scripts. It can also be used to load external resources such as configuration information or database connection information.

Differences from include

require and include are similar functions, but they differ in error handling:

• require: If the file does not exist, it triggers a fatal error.
• include: If the file does not exist, it will issue a warning but will not terminate the script.

Therefore, you should always use require to include required files, as in these cases the absence of the file will prevent the script from running properly.

Best Practices

• Make sure the file path is correct: Check carefully that the file path is accurate to avoid errors that the file does not exist.
• Use absolute paths: Using absolute paths (for example, /var/www/file.php) can avoid problems with file paths relative to the current script location.
• Avoid nested references: Overly nested references may cause performance issues and make debugging difficult.

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