Building a Simple Chat API with Sinatra and Ruby: Part 1 REST

Here’s an example of how you can build a simple Sinatra server to serve as a chat API in Ruby:

First, you’ll need to install Sinatra and any other dependencies you might need. You can do this by adding the following lines to your Gemfile and running bundle install:

gem 'sinatra'
gem 'sequel'  # or another database library if you prefer

Then, you can create a new file for your Sinatra server, let’s call it server.rb. In this file, you’ll first require the necessary libraries and set up your database connection:

require 'sinatra'
require 'sequel'  # or whichever database library you're using

DB = Sequel.connect('postgres://localhost/my_database')  # replace with your own database connection details

# You might also want to set up your database tables here, if you don't have them already
DB.create_table? :messages do
  primary_key :id
  String :sender
  String :recipient
  String :text
  Time :timestamp
end

Next, you can define your API routes and their corresponding behavior. For example, you might want to define a route to retrieve all messages in the chat history:

get '/messages' do
  messages = DB[:messages].order(:timestamp).all
  content_type :json
  { messages: messages }.to_json
end

You can also define routes to create new messages or delete existing ones:

post '/messages' do
  data = JSON.parse(request.body.read)
  sender = data['sender']
  recipient = data['recipient']
  text = data['text']
  timestamp = Time.now
  message_id = DB[:messages].insert(sender: sender, recipient: recipient, text: text, timestamp: timestamp)
  content_type :json
  { message_id: message_id }.to_json
end

delete '/messages/:id' do
  message_id = params[:id]
  DB[:messages].where(id: message_id).delete
  status 200
end

Finally, you can start your Sinatra server by running ruby server.rb. Your chat API will be available at http://localhost:4567, or whichever port you specify in your code.