Basic Experience Manager Web site extension
The following diagram shows how an out-of-the-box Experience Manager Web site extension works.
The Web site extension applies a special Claim Processor to establish that the request is made from Experience Manager. Based on that fact the Page content filter searches both the session database (in which content is stored that is not yet published) and the Content Data Store (which contains published content) for the requested page and its Component Presentations.
Upon finding fresher content in the session database than in the Content Data Store, the extension writes a special temporary file containing a session ID to a location relative to the Web application root. It forwards the original request to this new file.
This basic approach is sufficient if incoming HTTP requests point to actual files that are normally available in the Web application. If this is not the case (that is, if your Web application applies its own filtering), a custom solution is required.