postbin.rb

# Postbin
# -------
# A postbin for your localhost.
#
# Usage
# =====
#
# It's a Unix program. You run it from a shell.
#
#   $ ./postbin [-p PORT]
#
# I Heart Principles!!!
# =====================
#
# * Retain all the information about each HTTP request. More knowledge is more
# power.
# * Display each request in a useful way. It should be easy to see what's going
# on with your application by looking at application output or by using the web
# interface.
# * Fast. Quick startup, quick responses. This means small dependencies and
# less-clever code.
# * Easy to distribute. The ideal distribution is one file you put in your path
# and then use. The almost-ideal distribution is something like a homebrew
# recipe. An acceptable distribution is a gem.

require 'time'
require 'rack'
require 'leveldb'

class Postbin

  def initialize(db_path)
    @db = LevelDB::DB.new(db_path)
  end

  def call(env)
    req = Rack::Request.new(env)
    if req.post?
      save_request(req)
      send_ok
    else
      list_posts
    end
  end

  def save_request(req)
    timestamp = generate_timestamp
    blob = extract_metadata(req)
    @db[timestamp] = blob
  end

  def generate_timestamp
    Time.now.utc.to_i.to_s
  end

  def extract_metadata(req)
    derp = {
      url: req.path,
      headers: req.env.select { |k, v| k =~ /^HTTP_/ },
      body: req.body.read
    }
    Marshal.dump(derp)
  end

  def send_ok
    Rack::Response.new("OK")
  end

  def list_posts
    posts = db.map do |key, value|
      timestamp = Time.at(key.to_i)
      req = Marshal.load(value)
      p req
      headers = req.fetch(:headers, {}).map do |key, value|
        "#{key}: #{value}"
      end

      %Q{
        ---
        #{timestamp}
        #{req[:path]}
        #{headers.join("\n")}

        #{req[:body]}
      }
    end
    body = posts.join("\n")

    Rack::Response.new(body, 200, {"Content-Type" => "text/plain"})
  end

  def db
    @db
  end

end

if __FILE__ == $0
  Rack::Server.start(
    :app => Postbin.new('/tmp/posts'),
    :Port => 8080
  )
end