What is JSON-RPC ?

Welcome to the first blog post of this series consacred to my project of a JSON-RPC client implementation in Haskell.

Definition and description

JSON-RPC is a lightweight RPC protocol defining an encoding, JSON, and a transport, HTTP. It also defines notifications, requests not needing a response, and the protocol’s second version defines another possible transport, TCP/IP sockets, and a means of batching calls and notifications. However, due to its simplicity, it does not define neither authentication nor means of querying the server about implemented functions.

Why will I implement it ?

First of all, I’ll implement it because it is a simple textual RPC protocol, specifiying an already implemented in Haskell transport protocol. Another reason is that’s there are many implementations of this protocol, giving me the possibility to test my client against an already existing server. And it serves as a test of my capacities as an Haskell developper and as a spec reader. And there’s the fact that previous experience have told me that trying to tackle everything at once in my quest to be a better Haskell programmer is a bad idea: I’ll start with networking (without taking care of protocol details)… I’ll leave writing the network encoder and taking care of low level details to my next project…

Why Haskell ?

Cf. my post on RFC 707.

And after ?

The next blog post in this series will be consacred to the API my library will have and to the implementation choices I’ll make. After all, I have to choose between two versions of the protocol.

After this project, I’ll probably get back to my project of an RFC 707 implementation.


Projects list


Here are the list of my projects featured in this blog, with their status:

  • JSON-RPC client implementation in Haskell (started: repo is here)
  • RFC 707 implementation in Haskell (on hold)
  • ONC RPC client implementation in Haskell (not started)
  • AWT implementation in curses, using caciocavallo (not started)
  • Haskell compiler in Haskell (not started)
  • file(1) implementation using shared-mime-info as its source of information (started: see here) That project's in Perl.

For the time being, all my projects are on hold or not even started due to my studies…I will however talk about my RFC 707 implementation project, given it already started.

N.B. : I may do some of these projects also in other languages (e.g. Perl) if the fancy takes me.