What is the purpose of the AmbientData.HttpModule and PreviewContentModule?

Question

I find those two modules in Tridion driven application's web.config, I am not sure what is the purpose or whether I should comment it out. Anybody knows what they are for?

 <add name="Tridion.ContentDelivery.AmbientData.HttpModule" type="Tridion.ContentDelivery.AmbientData.HttpModule" />

<add name="Tridion.ContentDelivery.Preview.Web.PreviewContentModule" type="Tridion.ContentDelivery.Preview.Web.PreviewContentModule" />

Answer 1

The modules are for the Tridion Experience Manager in-context editing tool, also known as the "User interface update for SDL Tridion 2011 SP1".

Here are the docs: http://sdllivecontent.sdl.com/LiveContent/web/pub.xql?action=home&pub=UIU4SDLT2011SP1&lang=en-US.

The Ambient Data Framework is the module that integrates various products within the SDL Tridion product suite. For instance, the Context Engine, Smart Target, XPM and SDL Mobile are all integrated via the Ambient Data Framework. Have a look the the docs here: http://sdllivecontent.sdl.com/LiveContent/content/en-US/SDL_Tridion_2011_SPONE/concept_940F5B44E6F641BE8AE0C0D62C5D8874 (login required)

Answer 2

• PreviewContentModule: this is only used for XPM. And the responsibility of this module is to ensure that pages and/or any multimedia being retrieved from file system in the delivery site in context of xpm has the latest content.
• However the AmbientData.HttpModule is used by a lot of other conponents. This module is responsible for a datastore which is availble all through the delivery stack. For eg. It may contain data relating to the profile of the visitor, his/her geolocation, etc. however this is just the container. Other addons/containers push data to it to be used by some where else.