Question

I have multiple PHP classes with approximately 20 functions each all in one PHP file. Will the server store every class and every function in memory once I include this file?

Or will it only load the class and its functions once I instantiate like so?:

$ajax = new ajax();

Or will the server only cache the functions that I specifically call?:

$ajax->make_request();

I’m wondering if it is OK to have so many classes and functions housed in one single PHP file or if I should put in some type of logic that includes only the classes and functions that are required for the job.

Answer 1

I think you are a bit confused about how PHP works.

Every request the PHP parser, parses the requested file, e.g. index.php

If index.php include‘s another file, PHP will the parse that file.

Once a PHP file is parsed, it is stored in memory with “byte codes” (an almost machine language), during that request.

Regardless of how many functions or classes are in a file, it will all be stored in memory for that request.

There are extensions like APC that cache these parsed byte codes in memory between requests, but they need to be added on to PHP.

It is however better (in terms of memory usage) to use auto loading for your classes.

http://php.net/manual/en/language.oop5.autoload.php

PSR0 is a good set of guidelines for autoloading classes:

https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md