How to Build a Web App with and without Rails Libraries

mirth-4.rb

# mirth-4.rb
# Data persistence with YAML store:
# Use YAML to save the birthdays that
# can be reused when the server restarts

require 'socket'

# Require the library to use YAML::Store
require 'yaml/store'

server = TCPServer.new(1337)

# Attain file store from a YAML file 
store = YAML::Store.new("mirth.yml")

loop do
  client = server.accept

  request_line = client.readline
  method_token, target, version_number = request_line.split

  case [method_token, target]
  when ["GET", "/show/birthdays"]
    response_status_code = "200 OK"
    content_type = "text/html"
    response_message = "<ul>\n"

    # Get all the birthdays data in a hash object
    all_birthdays =  {}
    store.transaction do
      all_birthdays = store[:birthdays]
    end

    all_birthdays.each do |birthday|
      response_message << "<li> #{birthday[:name]}</b> was born on #{birthday[:date]}!</li>\n"
    end
    response_message << "</ul>\n"
    response_message << <<~STR
        <form action="/add/birthday" method="post" enctype="application/x-www-form-urlencoded">
        <p><label>Name <input type="text" name="name"></label></p>
        <p><label>Birthday <input type="date" name="date"></label></p>
        <p><button>Submit birthday</button></p>
      </form>
    STR

  when ["POST", "/add/birthday"]
    response_status_code = "303 See Other"
    content_type = "text/html"
    response_message = ""

    all_headers = {}
    while true
      line = client.readline
      break if line == "\r\n"
      header_name, value = line.split(": ")
      all_headers[header_name] = value
    end
    body = client.read(all_headers['Content-Length'].to_i)

    require 'uri' 
    new_birthday = URI.decode_www_form(body).to_h

    # Store the user-input birthday data
    # back into the YAML store
    store.transaction do
      store[:birthdays] << new_birthday.transform_keys(&:to_sym)
    end
  else
    response_status_code = "200 OK"
    response_message =  "✅ Received a #{method_token} request to #{target} with #{version_number}"
    content_type = "text/plain"
  end

  http_response = <<~MSG
    #{version_number} #{response_status_code}
    Content-Type: #{content_type}; charset=#{response_message.encoding.name}
    Location: /show/birthdays
    #{response_message}
  MSG

  client.puts http_response
  client.close
end

mirth.yml

---
:birthdays:
- :name: Gma
  :date: 01/01/2021
- :name: Tom
  :date: 02/01/2021
- :name: Sesame
  :date: 03/01/2021

Thank you for the great blog!

I found the typo.
In order for the program to work correctly, there needs to be a line break on the next line after Location: /show/birthdays which is on line 77.

---

Best regards,
s4na