Creating a PDO Object with Rewriting On - php

Question

I'm having a weird situation here.
I'm trying create a PDO object, like this:
$dbh = new PDO('mysql:host='.$hostname.';dbname='.$dbname,$username, $password);
I have rewriting ON in my .htaccess file. when I try to run the script using a URL that will trigger a rewrite rule, it shows me the following error:
Fatal error: Class 'PDO' not found
I have a exception rewrite rule for a directory where the script is, named PHP, like this:
RewriteRule ^(php)($|/) - [L]
if I run the scripting directly from the directory, it runs normally with no erros.
I don't know why this is happening. any clues?
Thank you

Answer 1

Edit: Ok, I saw I've misinterpreted your question a bit, but I still think there is something wrong about the php.ini path. Could you check the phpinfo() output of both web calls. The basic idea of the answer keeps the same as stated below (replace CLI with the second web call ;))
OLD ANSWER
Assuming, that you have one of the more common linux distributions (ubuntu, debian, suse, etc), you might have two (or more) php.ini files. One that is pulled when using the webserver module (which seems to be an apache) and one that is used for the cli env. php supports up to one php.ini per SAPI.
In newer debian and ubuntu systems php extensions are linked in the same manner as the sites-available/enabled in the apache config.
If you have a self compiled php look for a php-cli.ini at the common location for the php.ini (which is /usr/local/share/php by default). If a php-cli.ini is present it will be used instead of the php.ini for cli commands.
(Manual Reference: http://de2.php.net/manual/en/configuration.file.php)
How to find out:
Get the phpinfo() output for the INFO_GENERAL section from you webserver. To achieve this, create a simple php file in a web-accessible directory (e.g. the DocumentRoot). Remember to delete it after you got the information you need! Please adjust the '/var/www' to something that matches your config.
$> echo '<?php phpinfo(INFO_GENERAL);' > /var/www/info.php
Now go to your browser and open http://your.host.name/info.php and look for the config property "Configuration File (php.ini) Path". Note this somewhere or just leave the page open for later reference.
On your cli this is also quite easy. The example below is a snip from my shell.
mmueller#bsd ~$ php -i | grep ini
Configuration File (php.ini) Path => /usr/local/etc/php/5.5
Loaded Configuration File => /usr/local/etc/php/5.5/php.ini
[... omitted the tail]
Compare the two paths and see if they are different.
To see why this happens, please take a look at the 'Configure Command' section. You mighty find three important configure arguments. Those three influence where php looks for it's configuration.
'--sysconfdir=/usr/local/etc/php/5.5'
'--with-config-file-path=/usr/local/etc/php/5.5'
'--with-config-file-scan-dir=/usr/local/etc/php/5.5/conf.d'
If you want to ensure the same configuration, you can do one of the following things:
Just add extension=pdo_mysql to the webserver version and see if that is enough
Remove the additional CLI config (if present), this will make php use the php.ini for all SAPIs (make a backup of the file before you do that!). Then you need to merge the rules into the php.ini that you need. (In your case there seems to be an extension=pdo_mysql missing)
Check the webserver php.ini for anything that you do not want to have in the cli version, then copy the webserver php.ini over the CLI php.ini (Do a backup first).
Delete the cli or webserver php.ini, symlink the other php.ini to the place of the deleted one. (not the best way, but I've seen that a lot on customer servers).

Answer 2

Solve it.
There was a empty php.ini in the public_html, I deleted it, and it worked.
thank u all