Centralizing Common Methods and Constants in a PHP Application Using Config Files

In a PHP application, the Common.php file placed in the root directory stores shared methods that can be invoked from any other file.

The typical API response structure includes four fields: status (0 for error, 1 for success), message (error description), httpstatus (HTTP status code like 200 or 404), and data (the payload, which may be null when empty).

Because values such as the status codes and HTTP status numbers are used repeatedly, it is advisable to extract them into a separate configuration file for easier maintenance.

Solution

Creating the configuration file

Inside the config directory—intended for configuration files—create a new file (e.g., constants.php ) and define the constant values there.

Using the variables

Use the config() helper to read the values from the configuration file; the syntax config('constants.status_success') retrieves the constant defined in the specified file.

This approach treats the config directory as an object, each file as a class, and the dot notation as property access, making the code more readable and maintainable.