Finding the PHP File (at run time) where a Class was Defined

Question

Is there any reflection/introspection/magic in PHP that will let you find the PHP file where a particular class (or function) was defined?

In other words, I have the name of a PHP class, or an instantiated object. I want to pass this to something (function, Reflection class, etc.) that would return the file system path where the class was defined.

/path/to/class/definition.php

I realize I could use (get_included_files()) to get a list of all the files that have been included so far and then parse them all manually, but that's a lot of file system access for a single attempt.

I also realize I could write some additional code in our __autoload mechanism that caches this information somewhere. However, modifying the existing __autoload is off limits in the situation I have in mind.

Hearing about extensions that can do this would be interesting, but I'd ultimately like something that can run on a "stock" install.

Solution 1

Try ReflectionClass

• ReflectionClass::getFileName — Gets a filename

Example:

class Foo {}
$reflector = new \ReflectionClass('Foo');
echo $reflector->getFileName();

This will return false when the filename cannot be found, e.g. on native classes.

Solution 2

For ReflectionClass in a namespaced file, add a prefix "\" to make it global as following:

$reflector = new \ReflectionClass('FOO');

Or else, it will generate an error said ReflectionClass in a namespace not defined. I didn't have rights to make comment for above answer, so I write this as a supplement answer.

Solution 3

Using a reflector you can build a function like this:

function file_by_function( $function_name ){
    if( function_exists( $function_name ) ){
        $reflector = new \ReflectionFunction( $function_name );
    }
    elseif( class_exists( $function_name ) ){
        $reflector = new \ReflectionClass( $function_name );
    }
    else{
        return false;
    }
    return $reflector->getFileName();
}

file_by_function( 'Foo' ) will return the file path where Foo is defined, both if Foo is a function or a class and false if it's not possible to find the file

Comments

[Alan Storm]

Honest, non-asshole curiosity here. What made you think this answer was any better than the idea I'd already considered and rejected? " I realize I could use (get_included_files()) to get a list of all the files that have been included so far and then parse them all manually, but that's a lot of file system access for a single attempt."

[Seaux]

because its one line as opposed to however many lines it'd take to write a parser in PHP and the grep function is compiled C, i think, and likely much faster than whatever would have been written.

[Alan Storm]

Ah, got it. My actual concern was repeated disk access to each of the files over and over again to do this (it's something that will happen a lot in the tool I'm building) and not the amount of code I'll try to make that clearer next time. (FYI: You should look into ack. It's way better than grep!)

[Seaux]

ack or awk? I love awk, its actually my fav programming language, but more people use grep regularly...its "cleaner" for stuff this simple

[Alan Storm]

Not awk, ack: betterthangrep.com It's perl back grep replacement that's optimized for search code based projects. It's great.