just-json-server

Run a API server supporting CRUD with just a json file.

Prerequisite

Executables can be found on github release page

Build from source

Haskell build tool stack

Getting started

Create a json file with name, say db.json

{
  "articles": [
    {
      "id": 1,
      "title": "title 1"
    },
    {
      "id": 2,
      "title": "title 2"
    }
  ],
  "posts": [
    {
      "id": 1,
      "title": "post 1"
    }
  ]
}

Then, build and start an API server

# build from source code
stack build

# run the executable
stack exec just-json-server db.json

which supports CRUD operations on the given data, e.g.

# get all
GET /articles

# get one
GET /articles/1

# create
POST /articles

# update
PATCH /articles/1
PUT /articles/1

# delete
DELETE /articles/1

Development

Start api server with steeloverseer to watch file changes and restart automatically

Notes

CI scripts referenced from purescript

Why?

Because Haskell rocks!

This kind of json api server is super easy to implement in dynamic languages such as Nodejs. See json-server. Nonetheless, it's a very good way to practice writing Haskell code by re-implementing existing libraries.

During development, the only bugs I got were

accidentally passing resource name value (string) instead of resource id (also string) to some function
list calculation replaceOrInsertElem, which have to be verified by test cases

Other than that, when the program compiles, it is correct.

Performance-wise, re-implementing it with Haskell is rediculous, because the performance should be bounded by IO of the json file.