Is it possible to query all the files. As I found that we can get one file at a time and for that we need code for that particular file. But we need all the files. And One more question when we query any file then how we let to know about the file the type, its a pdf or doc etc.
The new REST implementation gives you more options:
We recently added some File API endpoints to the REST API, as John notes above.
However, GETs are only on a single file at a time, by design. If you need to retrieve all the File objects in a Infusionsoft Application, you can retrieve the list of Files from the REST endpoint and iterate the list to retrieve each file in turn.