Try and Catch

Shawazi

I know from using ini_set('display_errors', 1), I can make my script have a fatal error from going over the memory limit. I tried these lines of code:

try {
	$source_id_original = imagecreatefromjpeg($destination); // what causes memory failure from gigantic images
}
catch(Exception $e){
	echo 'Error :'.$e->getMessage().'<br />';
	echo 'Code :'.$e->getCode().'<br />';
	echo 'File :'.$e->getFile().'<br />';
	echo 'Line :'.$e->getLine().'<br />';
	exit();
}

It just blanks out of the page as usual instead of catching.

Shrike

Functions such as imagecreatefromjpeg() don't throw Exceptions, they work with the standard error handling mechanism. Now, it is possible using set_error_handler() to throw exceptions when some errors occur, but fatal errors are not available using this method. In PHP fatal is just that. No more processing will happen.

Exceptions in PHP are really meant for userland code. For example

function myFunction()
{
  throw new Exception( 'uh-oh' );
}
try
{
  myFunction();
}
catch( Exception $e )
{
  echo $e->getMessage();
}

A more thorough explanation is in the PHP manual.

theslinky

Shawazi, as a work-around, why not use filesize() or fstat() to get the size of the file before trying to open it? Just print an error if filesize returns a number close to your memory limit.

-sridhar

bradgrafelman

theslinky wrote:
Shawazi, as a work-around, why not use filesize() or fstat() to get the size of the file before trying to open it? Just print an error if filesize returns a number close to your memory limit.

-sridhar

Actually, when opening JPEG files, the memory consumed has nothing to do with the filesize but everything to do with the raw, uncompressed image size.