Why Should I Avoid `require_once` in PHP and What are Better Alternatives?

The Pitfalls of Using require_once and its Better Alternatives

The PHP coding community strongly advises against using require_once due to its potential performance impact. This article explores the reasons behind this recommendation and offers alternative solutions.

Why is require_once Inefficient?

Unlike class constants, PHP defines are notably expensive in terms of performance. Moreover, using require_once is unnecessary for including classes since class_exists() can handle this task adequately. If the file being included contains procedural code, using require_once is even more redundant.

Alternative Solutions

While using class_exists() as a replacement for require_once gained traction in the past, it was not an optimal solution. Recent PHP versions have significantly improved the performance of require_once, making conditional checks and method calls far less impactful.

A broader concern regarding PHP includes, in general, is their performance cost. Each include triggers a switch to parse mode and opcode generation, creating an overhead. For applications with a substantial number of includes, this can noticeably affect performance.

Considerations for Enhancing Performance

To mitigate the performance impact of includes, consider the following strategies:

• For applications with a well-defined set of required files, include them all upfront using require(). This allows the opcode cache to optimize the code more efficiently.
• If using an opcode cache is not possible, consider inlining includes into a single file during production (not during development). Note that this requires accurate knowledge of all required files.
• Autoload is a convenient yet slower solution due to the overhead of executing the logic behind it for each include. Use it sparingly for specialized files but avoid loading all necessary files this way.
• For applications with a small number of includes (around 10), optimizing other aspects like database queries may be more impactful than addressing includes.

The above is the detailed content of Why Should I Avoid `require_once` in PHP and What are Better Alternatives?. For more information, please follow other related articles on the PHP Chinese website!