php exec（'alpr'）返回一个安装了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!