使用MacPorts在Mac OS X 10.11上安装MongoDB
I am trying to install MongoDB on my computer running Mac OS X 10.11 (El Capitan).
My Apache + PHP configuration was already working correctly.
I installed MongoDB and PHP drivers for MongoDB through MacPorts:
sudo port install mongodb
sudo port install php55-mongodb
Installation ran correctly.
I added mongodb.so file to the extensions loaded in the php.ini file:
extension=/opt/local/lib/php55/extensions/no-debug-non-zts-20121212/mongodb.so
When I run phpinfo() function in php file, mongodb extension seems to be loaded correctly: 
I tried to test my connexion by initializing a MongoClient instance:
<?php
$mongoDB = new MongoClient();
var_dump($mongoDB);
?>
Unfortunately, I got a HTTP ERROR 500, and I got the following line in my Apache logs:
PHP Fatal error: Class 'MongoClient' not found in ...
Did I make something wrong ?
Finally found a solution to my problem.
As @neverpanic and @Zagonine made me understand, php-mongodb and php-mongo are not the same extension.
If you want to use old PHP driving classes, you should use php-mongo package instead of the very new php-mongodb.
Trying to install latest php-mongo extension, I had an other problem related to OpenSSL. To bypass it, I installed an old version of php-mongo extension:
sudo /usr/local/pear/bin/pecl install mongo-1.5.8
Hopefully it will help someone else.
On most of site I saw you need to add the extension mongo.so and not mongodb.so in your php.ini.
If it's not solved your problem, I recommand you to install MongoDB Drive with PELC.
Run command line:
$ sudo pecl install mongo
And add this line to your php.ini:
extension=mongo.so