JSON API

This recipe will help you to setup a basic JSON API response in your application.

First you need an amber project generated with Amber CLI or from scratch.

To create a JSON API from the command line, you simply need to use the API generator. Or for quick reference, run:

amber g api Post title:string entry:integer

And it will generate the following files:

04:09:54 Generate | (INFO) Generating Amber::CLI::Api
04:09:54 Generate | (INFO) new spec/models/post_spec.cr
04:09:54 Generate | (INFO) identical spec/models/spec_helper.cr
04:09:54 Generate | (INFO) new src/models/post.cr
04:09:54 Generate | (INFO) new db/migrations/20191031160954280_create_post.sql
Format ./config/routes.cr
04:09:54 Generate | (INFO) new spec/controllers/post_controller_spec.cr
04:09:54 Generate | (INFO) identical spec/controllers/spec_helper.cr
04:09:54 Generate | (INFO) new src/controllers/post_controller.cr

This is a fully scaffolded JSON API.

Custom

If you don't need full CRUD, you can also create a custom JSON API.

class SomeController < ApplicationController
def json_api
# You can easily access the context
# and set content_type like 'application/json'.
# Look how easy to build a JSON serving API.
context.response.content_type = "application/json"
data = {name: "Amber", age: 1}
data.to_json
end
end

Then in your routes file:

config/routes.cr
config/routes.cr
Amber::Server.configure do |app|
pipeline :api do
# pipelines...
end
‚Äč
routes :api do
# other routes,,,
get "/json_api", SomeController, :json_api
end
end

Alternatively you can use respond_with helper. Here you don't need to setup content_type, however the requested path requires a .json extension, by example /json_api.json

class SomeController < ApplicationController
def json_api
data = {name: "Amber", age: 1}
respond_with do
json data.to_json
end
end
end

For a full CRUD example, see JSON API full CRUD.

Also see Respond With and Response & Request.