How do I know if a file is required?

Question

I created a global php file (globs.php) and demanded it on all my pages. However, some pages now include other pages, and I get an error when it tries again to request globs.php.

How to determine if a file is required? That way I could do if required ("globs.php") required ("globs.php").

Answer 1

You can also create your own require_file function:

<?php function require_file($file_path){ static $required_files=array(); if(!isset($required_files[$file_path])){ require $file_path; $required_files[$file_path]=true; return true; } return false; } ?> 

Answer 2

Use require_once instead:

The _require_once_ operator is identical to require , except that PHP checks to see if the file has already been included, and if so, do not include (required) again ...

Answer 3

array get_included_files (void)

http://www.php.net/manual/en/function.get-included-files.php

Gets the names of all files that were included with include , include_once , require, or require_once

Return values

Returns an array of the names of all files.

The script that is initially called is considered to be an “included file,” so it will be listed along with the files referenced by include and family.

Files that are included or required multiple times are displayed only once in the returned array.

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get_included_files() example

 <?php // This file is abc.php include 'test1.php'; include_once 'test2.php'; require 'test3.php'; require_once 'test4.php'; $included_files = get_included_files(); foreach ($included_files as $filename) { echo "$filename\n"; } ?> 

The above example outputs:

 abc.php test1.php test2.php test3.php test4.php 

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Answer 4

The best solution is require_once (), which uses the same syntax as require (), but performs the check you are talking about automatically.

If you really need to know if this is required, I suggest defining a constant in your included file and checking its value.

Answer 5

Assuming there is a function in the file you want to include, you can also quickly execute

  if (!function_exists('foo')) { require('bar.php'); } 

Use what works best for your installation.