SAPI is the Server abstraction API and you can access server-related global variables using the SG() macro. Include SAPI.h in your .c file to get the SG macro. You can then access the elements of the sapi_globals_struct which looks like this:

To access the default MIME type, you would use:

And to access the request_uri you would use:

Executor Globals
These are run-time globals. The ones you are likely to be interested in are the symbol_table and active_symbol_table globals. For example, to access the user-space $foo variable from the current global context, you would do this: