Relative path not working in cron PHP script

Question

If a PHP script is run as a cron script, the includes often fail if relative paths are used. For example, if you have

require_once('foo.php');

the file foo.php will be found when run on the command line, but not when run from a cron script.

A typical workaround for this is to first chdir to the working directory, or use absolute paths. I would like to know, however, what is different between cron and shell that causes this behavior. Why does it fail when using relative paths in a cron script?

This is a great resource as well: http://stackoverflow.com/questions/2857712/enable-proper-relative-path-in-cron — Ben, May 18 '10 at 14:03
Don't change your PHP files just to make them work from a cron job, instead change the current directory on the cron job line. Check my answer [here](https://stackoverflow.com/a/55385788/5407848). — Accountant م, Apr 09 '19 at 20:32

score 110 · Answer 1 · edited Apr 12 '14 at 17:30

110

Change the working directory to the running file path. Just use

chdir(dirname(__FILE__));
include_once '../your_file_name.php'; //we can use relative path after changing directory

in the running file. Then you won't need to change all the relative paths to absolute paths in every page.

edited Apr 12 '14 at 17:30

Taz

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answered Jul 30 '11 at 05:56

Withfriendship Hiox

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This was driving me mad. This sorted it out perfectly – Andy Davies Jan 22 '13 at 14:14
5

You can also use `chdir(__DIR__);` which is a bit more concise. – But those new buttons though.. Feb 01 '15 at 18:57
this only works if you can execute `chdir()` in your environement. `include/require dirname( __FILE__ )` is much more reliable. – aequalsb May 27 '15 at 21:39
I don't like to change the PHP code, instead change the directory at the cron tab, check [my answer](https://stackoverflow.com/a/55385788/5407848) – Accountant م Mar 27 '19 at 20:29

score 14 · Accepted Answer · answered Jan 14 '10 at 13:58

The working directory of the script may be different when run from a cron. Additionaly, there was some confusion about PHPs require() and include(), which caused confusion about the working directory really being the problem:

include('foo.php') // searches for foo.php in the same directory as the current script
include('./foo.php') // searches for foo.php in the current working directory
include('foo/bar.php') // searches for foo/bar.php, relative to the directory of the current script
include('../bar.php') // searches for bar.php, in the parent directory of the current working directory

score 7 · Answer 3 · edited Aug 30 '12 at 08:35

7

The only chance I got "require_once" to work with cron and apache at the same time was

require_once(dirname(__FILE__) . '/../setup.php');

edited Aug 30 '12 at 08:35

Sjoerd

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answered Aug 30 '12 at 08:02

jansch

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aequalsb · Answer 4 · 2015-05-27T21:33:48.247

Because the "current working directory" for cron jobs will be the directory where your crontab file exists -- so any relative paths with be relative to THAT directory.

The simplest way to handle that is with dirname() function and PHP __FILE__ constant. Otherwise, you will need to edit the file with new absolute paths whenever you move the file to a different directory or a server with a different file structure.

dirname( __FILE__ )

__FILE__ is a constant defined by PHP as the full path to the file from which it is called. Even if the file is included, __FILE__ will ALWAYS refer to the full path of the file itself -- not the file doing the including.

So dirname( __FILE__ ) returns the full directory path to the directory containing the file -- no matter where it is included from and basename( __FILE__ ) returns the file name itself.

example: Let's pretend "/home/user/public_html/index.php" includes "/home/user/public_html/your_directory/your_php_file.php".

If you call dirname( __FILE__ ) in "your_php_file.php" you would get "/home/user/public_html/your_directory" returned even though the active script is in "/home/user/public_html" (note the absence of the trailing slash).

If you need the directory of the INCLUDING file use: dirname( $_SERVER['PHP_SELF'] ) which will return "/home/user/public_html" and is the same as calling dirname( __FILE__ ) in the "index.php" file since the relative paths are the same.

example usages:

@include dirname( __FILE__ ) . '/your_include_directory/your_include_file.php';

@require dirname( __FILE__ ) . '/../your_include_directory/your_include_file.php';

score 3 · Answer 5 · answered Dec 28 '09 at 13:13

Another possibility is that the CLI version is using a different php.ini file. (By default, it'll use php-cli.ini and fallback to the standard php.ini)

Also, if you're using .htaccess files to set your library path, etc. this obviously won't work via the cli.

score 3 · Answer 6 · answered Feb 01 '15 at 19:03

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In addition to the accepted answer above, you can also use:

chdir(__DIR__);

answered Feb 01 '15 at 19:03

But those new buttons though..

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only if you are allowed to execute `chdir()` in the environment you're in – aequalsb May 27 '15 at 21:37
is that common? I've never worked in any environment where that function wasn't allowed. – But those new buttons though.. May 28 '15 at 02:36
i have experienced it related to PHP safe_mode. http://php.net/manual/en/features.safe-mode.functions.php, but this has been deprecated http://php.net/manual/en/features.safe-mode.php. -- that's deprecated not removed... meaning, it could still be encountered. – aequalsb May 28 '15 at 15:43

score 2 · Answer 7 · answered Dec 28 '09 at 13:06

2

When executed trough a cron job your PHP script probably runs in different context than if you start it manually from the shell. So your relative paths are not pointing to the right path.

answered Dec 28 '09 at 13:06

Jan Hančič

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that's right. In fact, the script's working directory is the working directory of the shell. Should use absolute pathnames. – mauris Dec 28 '09 at 13:10
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absolute path names are a nightmare to manage as you move files around... just use `dirname( __FILE__ )` – aequalsb May 27 '15 at 21:36

score 0 · Answer 8 · answered Jan 28 '13 at 00:19

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The DIR works although it will not work on my localhost as it has a different path than my live site server. I used this to fix it.

    if(__DIR__ != '/home/absolute/path/to/current/directory'){ // path for your live server
        require_once '/relative/path/to/file';
    }else{
        require_once '/absolute/path/to/file';
    }

answered Jan 28 '13 at 00:19

Jordan Rumpelstiltskin Nemrow

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still using a conditional statement that can be replaced by `dirname( __FILE__ )` – aequalsb May 27 '15 at 21:35

Relative path not working in cron PHP script

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