Pull 1

app.rb

@@ -0,0 +1,28 @@
+require_relative 'time_formatter'
+class App
+  def call(env)
+    @request = Rack::Request.new(env)
+    time_service_call
+  end
+
+  def time_service_call
+    return response(404, 'Path error or time format is nil') if (@request.path != '/time' || user_input.nil?)
+
+    time_service = TimeFormatter.new(user_input)
+    if time_service.input_valid?
+      response(200, time_service.time_output)
+    else
+      response(404, "Unknown time format(s): #{time_service.unknown_formats}")
+    end
+  end
+
+  private
+
+  def response(status, content)
+    Rack::Response.new([content], status, { 'Content-Type' => 'text/plain' }).finish
+  end
+
+  def user_input
+    @request.params['format']&.split(',')
+  end
+end

config.ru

@@ -0,0 +1,2 @@
+require_relative 'app'
+run App.new

time_formatter.rb

@@ -0,0 +1,24 @@
+class TimeFormatter
+  attr_reader :user_input
+
+  FORMATS = { 'year' => '%Y', 'month' => '%m', 'day' => '%d', 'hour' => '%H',
+              'minute' => '%M', 'second' => '%S' }.freeze
+
+  def initialize(user_input)
+    @user_input = user_input
+  end
+
+  def input_valid?
+    unknown_formats.empty?
+  end
+
+  def unknown_formats
+    @unknown_formats = user_input - FORMATS.keys
+  end
+
+  def time_output
+    output = []
+    user_input.each { |el| output.push(FORMATS[el]) if FORMATS[el] }
+    Time.now.strftime(output.join('-'))
+  end
+end