wordpress: how to include a php file in frontend AND admin area (Fatal error: Cannot redeclare myfunction())

Question

I have some troubles to include a file called myplugin_functions.php

This php file contains functions that are required to make some functions work in the wordpress admin area. For that reason I include this file in backend pages using:

include( plugin_dir_path( __FILE__ ) . 'myplugin_functions.php');

This works perfectly.

When I do the same thing on frontend pages, the frontend can access these functions. Great.

But when I then navigate to the backend I get an error message

Fatal error: Cannot redeclare myfunction() (previously declared in /www/htdocs/...) in /www/htdocs/..../myplugin_functions.php on line 28

include_once() makes the problem vanish. But I think wordpress doesn't like including the same php functions for frontend and backend.

Do you know why? What is the best practice to get around this?

Thank you?

the problem is that it is included multiple times. when I use include_once() the problem vanishes. But I dont think that this is best practice — Ben Spi, Sep 06 '14 at 09:49
you are right, use include_once(), yes we don't do like this. — sprytechies, Sep 06 '14 at 09:51
@sprytechies: Why dont you like this? I would like to write DRY code, this is why I dont want to repeat identical code lines — Ben Spi, Sep 06 '14 at 09:53

score 1 · Accepted Answer · answered Sep 06 '14 at 09:59

wordpress uses the same functions for frontend and backend.....you're prob getting confused with ajax functions which are hooked seperately.

If you are including the file within a function, use require_once/ include_once. If you want the functions to be available to the entire directory, place require_once in your theme functions or plugin file file but then don't include when using functions.

require_once / include_once are actually good practice btw :)

wordpress: how to include a php file in frontend AND admin area (Fatal error: Cannot redeclare myfunction())

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