Most Infrastructure Map Server pages follow a similar processing flow. First, they create a connection with the site server using an existing session id. Then they open connections to any needed site services. The exact services required depend on the page function. For example, a page that deals with map feature data requires a feature service connection.
Once the site connection and any other service connections are open, the page can use Infrastructure Map Server Web API calls to retrieve and process data. Output goes to the task pane or back to the Viewer. See for details about sending data to the Viewer.
Infrastructure Map Server pages written in PHP require one additional step because PHP does not support enumerations compiled into extensions. To deal with this limitation, PHP Web Extension pages must include constants.php, which is in the mapviewerphp folder. This is not required for ASP.NET or JSP pages.