Creating a dummy API using Sinatra.

Install Sinatra gem

gem install sinatra

api_app.rb

require 'sinatra'
require 'json'
get '/' do
  'Hello world!'
end
post '/sign_in', provides: ['json'] do
  request.body.rewind
  request_payload = JSON.parse(request.body.read)
  
  if request_payload['username'] == 'email@domain.com' && request_payload['password'] == 's3cr3t'
    {data: {access_token: '2y7348y43tj04fdafdsfds'}, message: nil, success: true}.to_json
  else
    {data: nil, message: "Unauthorized", success: false}.to_json
  end
end

Starting the app

ruby api_app.rb -o 0.0.0.0

The -o 0.0.0.0 allows you to access the app over the local network. It’s similar to rails s -b 0.0.0.0

What next

Here a challenge. Use SQLite to store data.