PHP - PSR 0 - Configuration Constants

Question

This question is about PSR-0 autoloaded libraries and the way main configuration constants should be declared and used.

From your point of view (lib/framework developer), where/how should be declared your library configuration PHP constants (such as ESCAPE_SOMETHING, USE_DOM, API_URL, ...) in such a way that

• your code can easily address them
• client code can easily modify them depending on needs

Is there any convention, recommendation, or even something I missed in PSR-0 I should be aware of?

• Jérôme: I am wondering if they could go directly into the file which contains the autoloader logic itself. However, I do not like the fact that people will have to edit this file to modify configuration.

Answer 1

This question is about PSR-0 autoloaded libraries

I think you're conflating two different issues. Finding and loading the PHP code for FooClass is (or ought to be) a different problem from how new FooClass() or FooClass::staticThing() should behave.

Ideally, FooClass shouldn't care whether I (the guy using the library) relied on an autoloader or whether I hard-coded my own require_once() statement.

library configuration PHP constants

One ground-rule first... never with constants from define(). Polluting the global namespace is a bad idea, and IIRC even the new namespace features are a little weird in that regard. Class-constants on the library classes are acceptable, but as the library-consumer you probably aren't hand-editing those.

From your point of view (lib/framework developer), where/how should be declared your library configuration PHP constants

You mean, how would I prefer for consumer code to set options that affect my code? I'd prefer something like:

FooLibraryConfigurator::set("a","b");
FooClass::doStuffThatNeededConfData();

In other words, configure my library based on a mechanism I created for you to use. :p