php exec（'alpr'）返回安装了openALPR的空数组

Question

I am writing a php script that makes use of openALPR installed on my linux computer.

When I type "alpr --version" in the terminal, I get this output

alpr  version: 2.2.4

But then when I do this in my php script, I get an empty array result. But any other command works just fine.

Here is my code snippet

$command = 'alpr --version ';
$result = array();

exec($command, $result);

var_dump($result);

I will appreciate any help

Answer 1

You are probably running that command from the terminal as a different user.

Find out which user php and/or apache is using, then switch user in the terminal.

Try and run the command again.

If the command isn't found, switch back to yourself and type which alpr , which will give you the path.

Then switch back to PHP's user, and ensure the $PATH environment variable includes the folder where the alpr executable is found.

Also, make sure that the executable is actually executable by that user/group. If not, you'll need to use chmod or chown or chgrp to give PHP permission.

If you get stuck, leave a comment!