PHP Configuration – Extensions

Sasa Bogdanovic — Sun, 11 Jul 2010 21:31:23 +0000

When Apache starts, it loads PHP module and its extensions based on configuration in php.ini file. Once started, it is easy to see which extensions were loaded by using PHP’s phpinfo() function. Not only it will output detailed information on PHP configuration, it will also note which php.ini file was loaded, which is very useful in case thereare several php.ini files in the file system.
To use the function, simply create new file called e.g. myphpinfo.php in the root directory of web server, with the following content:




phpinfo();

?>

In the browser, navigate to the newly created file, e.g. http://www.example.com/myphpinfo.php and you will see a large amount of information about the current state of PHP in your web server.
As from PHP 5.2.2, “Loaded Configuration File” information was added, and it tells which php.ini file was used on Apache startup. That is the one you need to modify in order to change PHP configuration.
To enable/disable PHP extensions, open php.ini file in your editor of choice and comment/uncomment the ones you need to affect.
After saving the changes, Apache needs to be reloaded for them to come into effect.
On Ubuntu, issue the command

sudo /etc/init.d/apache2 reload

The same applies if order of extensions needs to be changed, as is the case in enabling PHP EXIF extension.

PHP EXIF Extension

Sasa Bogdanovic — Sat, 13 Feb 2010 07:33:57 +0000

EXIF (Exchangeable image information) data provide digital image metadata. This information is stored in the header of the image in JPEG or TIFF format. It can be very detailed (even thumbnails can be embedded) and is included in the file size of the image. In PHP web applications it is very easy to extract the available information, however, there are some prerequisites that need to be met.

EXIF extension is a standard part of PHP distributions, but it must be enabled in php.ini file in order to use its functions. On windows, EXIF extension also depends on mbstring, an extension that provides multi-byte string parsing. Moreover, the sequence of enabling extensions in php.ini file does matter. If exif is enabled prior to mbstring, EXIF functions will not be available at run-time.

mbstring extension must be enabled before EXIF!

If you need to use EXIF functions in your environment, be it development or production, this is something you need to keep in mind. By default, extensions are ordered in alphabetical order in php.ini file. This makes it very easy to run into situation when you start banging your head against the wall as you don’t realize why function_exists('exif_read_data') keeps returning FALSE even though you have enabled both EXIF and mbstring extensions. Recently I needed a quick setup of development environment on my laptop and downloaded WAMP server, probably the most popular WAMP stack available, and I run into the that situation.

I find it really awkward. Including extensions in alphabetical order does not make any sense when there are dependencies like this.

RudiBela Business Solutions » EXIF

PHP Configuration – Extensions

PHP EXIF Extension