Interview questions ruby/rails

questions.rb

# Open ended
#   - What's your style of working. Pair programming vs solo
#   - What's your favortite pattern. Do you use any?
#   - If you accidentally pushed your branch to origin master, how would you restore
#     to a clean master?
#   - What have you been working on Sinatra and Node? Coffescript? APIs? how was it
#     architectured

# Loading only one columsn and handling sum back in SQL
# rails/activerecord. 
# difficulty: 3
class Customer < ActiveRecord::Base
  has_many :loans
end

class Loan < ActiveRecord::Base
  belongs_to :campaign
end

# Tentative answer:
class Customer < ActiveRecord::Base
  def funds_raised
    loans.sum(:amount)
  end
end


# Middleware question:

# How would you fix this to return a more descriptive error
# rails/sinatra. 
# difficulty: 7

curl -H "Accept: application/json" \
-H "Content-type: application/json" \
'http://localhost:3000/posts' \
-d '{ i am broken'

{"status":"400","error":"Bad Request"}%


# Enumerables questions:
# ruby
# difficulty: 5

class Signer < Struct.new(:key_id, :uid)
  def signed_by?(receiver)
    !rand(2).zero?
  end
end
signers = [ #<Struct Signer>, #<Struct Signer>, #<Struct Signer>]

# build an array of all uids => inject < flatmap
# build a hash from an array of signers
# return a boolean from signers to determine if all have been signed by signer


# OOD/ Refactoring question:
# Build a parser class that can handle different types :xml, :html, :css, :json, etc.
# Ruby. Difficulty: 7 

class Parser
  def parse(type)
    switch type
    ....
  end
end

---
class XmlParser 
  def parse
    puts "Xml parsing"
  end
end

class HtmlParser
  def parse
    puts "html parsing"
  end
end

class GenericParser
  TYPES = { :xml => XmlParser, :html => HtmlParser  }

  def initialize(type)
    @parser = initialize_parser(type)
  end

  def parse
    @parser.parse
  end

  def initialize_parser(type)
    if TYPES[type].present? 
      TYPES[type].new
    else
      raise TypeError, "No such a parser exists" 
    end
  end
end

parsed = GenericParser.new(:xml)