Adding Client API Support To A Filesystem

The client API feature was added in the JFileServer 1.4.0/JFileServer Enterprise 1.3.0 release, as an optional interface a filesystem can implement. The client API interface allows a client to send requests to the file server over existing protocols, currently SMB2 and SMB3 protocols are supported. A filesystem must implement the core DiskInterface, and can then add other functionality using optional interfaces such as to implement file locking, or in this case the client API interface.

The client API uses a special path on the server that the client can write a request into, and receives the response from the server. The special path is not visible in folder listings. The main implementation uses JSON format to send request and for the response, but you can implement your own format of request and response by implementing the lower level ClientAPIInterface, rather than extending the JSONClientAPI implementation.

The JSON client API has a client side application, currently for Windows 10 and 11, that provides a right click context menu into the Windows File Explorer application, with a configurable set of sub-menus that trigger server side actions. The client side application is also able to display message boxes and other user interface items before and after an action has run, show notifications, run applications and open URLs all under control of the server side actions.

The fileServersNG Alfresco add-on module contains a reference implementation of a client API, using the JSONClientAPI. There is a Wiki document that describes the fileServersNG client API implementation here, and the source code for the fileServersNG implementation is [here].