Include vs. Require in PHP: When Should You Use Each?

Include vs. Require in PHP: Understanding the Difference

When working with PHP, you may have come across the terms "include" and "require." Both are used to include external files, but they differ in their behavior and security implications. Let's explore their key differences:

Error Handling:

• require: If the specified file cannot be loaded, it throws a PHP Fatal Error and halts the execution of your script.
• include: In case of failure to find the file, it generates a warning but allows the script to continue running.

Performance:

• Both "include" and "require" have negligible performance differences when the required file is found. However, if the file is not present, "include" is slightly faster as it only produces a warning instead of terminating the script.

Security:

• require: Using "require" is generally recommended from a security standpoint. As it halts the script if the file cannot be loaded, it prevents potential errors or attacks that might exploit missing files.
• include: Since "include" doesn't cause script termination, it's less secure and could potentially allow for malicious code execution if critical files are missing.

Example Illustration:

The difference between "include" and "require" in error handling:

require 'functions.php'; // Triggers a fatal error if 'functions.php' is not found

include 'functions.php'; // Outputs a warning but doesn't stop the script

Which to Choose?

In general, it's advisable to use "require" unless you specifically need the script to continue despite a missing file. "Require" ensures a safer and more predictable execution flow, making it the preferred choice for most use cases.

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