require_once fails on a readable file php wordpress site - php

Question

I have a php script that is really simple, but requires some of the wordpress includes. I have used the code from their website for most of it but it is failing whenever I try to call the require_once parts of the scripts. here is the relevant code:
$fn = dirname(__FILE__) . '/wp-admin/includes/media.php';
if(!file_exists($fn))
{
echo 'No File';
}
if(!is_readable($fn))
{
echo 'File is unreadable';
}
require_once $fn;
Interstingly enough, The only echo that I get when the require_once is uncommented is the full path to the document. The file is both existing and readable. However, when I uncomment the require_once code it comes back with a 500 error.
On a slightly related point. What is the easiest way of debugging php. I haven't found anything that is VS easy yet (or even as easy to debug as Django!!)

Answer 1

PHP has various settings in php.ini for how logging works. You can also set them at runtime. It might be logging to a file somewhere rather than displaying the error. Consider trying:
error_reporting(E_ALL)
To debug your application. Don't leave it on when you're done working with it.

Answer 2

You should be developing and debugging the code locally on your workstation, not on a shared hosting server. On your local workstation you have access to the php.ini, Apache error log, and the PHP error log. You can also set project-specific settings for debugging using .htaccess files. For example, you can configure separate PHP error log files for each different project you're working on.
As #Steve Howard pointed out, there are many settings you can alter in the php.ini in order to get more detailed error reporting. In fact, most LAMP packages install a development copy of the php.ini, which is basically a template of a php.ini file that's optimized for detailed error reporting. Detailed error reporting is something you want on your local environment for debugging. It is NOT something want on your production environment where customers and potential hackers will end up seeing more information than they should!
If you don't know how to set up PHP on your workstation, take a look at XAMPP, MAMP, Macports, etc. There are many options. You don't need to be super technical to get a stack set up on your computer. Once you have a good dev environment setup on your computer you can tail the PHP error log and the Apache log.
One thing I like to do is to use the PHP error_log() function. This allows you to output custom messages to the PHP error log. For example, if I'm debugging code and I need to know what the value of $foo is, I can do something like this:
<?php
error_log("Foo is: " . print_r($foo, true));
This is much better than using var_dump() or echo to print debugging data to the screen because it won't interrupt the normal execution of the program or the display of its view layer.