Question

I am trying to convert PDF to JPG file with this code:

$pdf_file = 'text.pdf';
$save_to = 'demo.jpg'; //make sure that apache has permissions to write in this folder! (common problem)
//execute ImageMagick command 'convert' and convert PDF to JPG with applied settings
exec('convert '.$pdf_file.' '.$save_to, $output, $return_var);

if($return_var == 0) { //if exec successfuly converted pdf to jpg
print "Conversion OK";
}
else print "Conversion failed.<br />".$output;

And I get message Conversion OK but image file don’t creates. When I tried this on the different server, then everything works.
Permissions for root catalog are set to 777. I don’t have any idea why it doesn’t work… I don’t know which versions of Imagemagick are installed on both servers. Maybe that is the problem ? In phpinfo() there is no information about version or anything.

Answer 1

You are having trouble running “convert” because the PHP function exec() has been disabled in your php.ini file.

When a exec() command is failing there are multiple steps that can be taken to troubleshoot the problem:

1. Verify if safe mode is on. Specifically the docs say:

   Note: When safe mode is enabled, you can only execute files within the
   safe_mode_exec_dir. For practical reasons, it is currently not allowed
   to have .. components in the path to the executable.

2. Turn on Error Reporting too see if that gives any more information. This can be accomplished by adding code like the following to the top of your script:

   ini_set('display_errors', 1);
   ini_set('error_reporting', E_ALL);
   

3. Simplify the exec() command to something that should always work:

   exec('/bin/echo helloWorld',$output);
   var_dump($output);
   

In your specific case when you tried step #3 above, it returned null. Null is what PHP returns when the exec() function is disabled. Also, if you were able to turn on error reporting (step #2) the output would have looked something like the following:

PHP Warning:  exec() has been disabled for security reasons in /home/path/to/file.php on line 2
NULL

The solution to this problem is to enable the exec function in php.ini or go to a host/server that allows the function to be used.