PHP mysqli works in command line, but not on pages

Question

Red Hat Linux Server, Apache 2.2, PHP 5.5.4

When I run this in the command line, everything seems to be fine:

php -r '$mysqli = new mysqli("127.0.0.1", "un", "pw", "things", "3306");'

At the same time, I have a .php document which doesn't run. I get this error...

PHP Fatal error: Class 'mysqli' not found in [/path/to]/vars.php on line 2

from this code:

<?php
    $mysqli = new mysqli("localhost", "un", "pw", "things", "3306");
?>

Other .php pages (which don't use mysqli) work fine. Any idea what's going on here? Thanks in advance.

Answer 1

Like I said, today I was facing the exact same issue with Apache 2.4, PHP 5.5.12, Windows Server 2008.
But I was able to solve this.

Diagnostics:
I ran phpinfo() in both my command prompt as well as on the web server/browser and noticed that path of the php.ini files were different in both. Now, I realised that I need to force set the path to the php.ini file in Apache.

Solution:
I fixed this by pointing to the correct php.ini and dll files on my Apache server. In the httpd.conf file I wrote these lines in sequence.

PHPIniDir "C:/path/php/php5.5.12"
LoadFile "C:/path/php/php5.5.12/php5ts.dll"
LoadModule php5_module "C:/path/php/php5.5.12/php5apache2_4.dll"  

The first line alone fixed the issue.

Answer 2

I've asked almost the same question on Unix Stack Exchange; this was how the issue got resolved.

Sometimes restarting Apache has no effect even after rebooting, but stopping the httpd service and starting it again worked for me:

On Fedora

sudo systemctl stop httpd && sudo systemctl start httpd

On systems without systemd (like Ubuntu) you can probably can use something like this (didn't test it):

sudo service apache2 stop && sudo service apache2 start

reference: How to install php + mysql on Fedora?