Extension Config

com_config

First go to the administration side of a Joomla site and view the System > Global Configuration page

You should be able to see links to the configuration options available in all the components. Take a look at the uri:

/administrator/index.php?option=com_config

The backend of the Joomla, unlike the frontend doesn't use SEF URIs (for obvious reasons I hope) so its a good opportunity to look at how Joomla internal input query is working. The query option=com_config means that you're looking at the default view of the component com_config. Now click on the link to the component configuration of 'articles'. Now you're at:

/administrator/index.php?option=com_config&view=component&component=com_content

The config component provides a settings interface for any installed and active component that has a config.xml at the base of its administration folder. So go and look at the xml file at /administrator/components/com_content/config.xml If your administrator folder isn't protected you can look at it right in the browser, but otherwise just open up the file.

The xml is the schema for the settings form and the format of the fields and fieldsets is something you can see in lots of places in Joomla. Joomla has a form class called jform which is used for just about every form that you will see.

Using JForm

One exception that you may wish to not think about right now is right at the bottom of the confix.xml where it has a field called rules. This calls in another xml /administrator/components/com_content/access.xml which sets up the options for the user access control interface.

Ok, now if possible go and look in the database table yourprefix_extensions and look for the row with the name com_content in the params column you'll see the data that belongs to that settings form. The access rules however are kept in the yourprefix_assets table just cause there's not a 1 to 1 relation between everything installed and everything with access rules. Should you ever manipulate the config.xml or access.xml of a core component? No. Should you be changing data in the extensions table directly? Very rarely and probably never. But it's get an understanding of what it means for Joomla extentions to 'be installed' and how some core components are there to support the CMS and other extensions.