A Sinatra proxy to be used over a neo4j ReST API

web.rb

# web proxy for a neo4j database, using Heroku but could be easily modified for anything else
# this code is a modified version of the code found here  https://github.com/akollegger/nosql-now/blob/master/web.rb
# the main changes are...
#  - authentication required for modification, although viewing is allowed without authentication (auth can be added by calling protected! in the get method)
#  - the domain returned in the data is replaced with the proxy domain instead of being removed which was causing errors in the java jersey library
#  - modified post routing, this wasn't catching all POST requests

require 'sinatra'
require 'rest-client'
require 'json'

neo4j_db_url = ENV['NEO4J_URL'] || "http://localhost:7474"
neo4j_db_url_noauth = neo4j_db_url.gsub /http:\/\/\w+:\w+@/, "http://"

# SECRET STUFF!  put your user name and password and URL for the Heroku app here
neo4j_user = ""
neo4j_password = ""
HEROKU_APP_HOST = ""

REPLACE_DB_HOST = /(#{neo4j_db_url})|(#{neo4j_db_url_noauth})/
REST = RestClient::Resource.new neo4j_db_url, neo4j_user, neo4j_password

helpers do
  def protected!
    unless authorized?
      response['WWW-Authenticate'] = %(Basic realm="Restricted Area")
      throw(:halt, [401, "Not authorized\n"])
    end
  end

  def authorized?
    @auth ||=  Rack::Auth::Basic::Request.new(request.env)
    @auth.provided? && @auth.basic? && @auth.credentials && @auth.credentials == [neo4j_user, neo4j_password]
  end
end

get '/' do
  if request.accept.include?("application/json") || request.accept.include?("text/javascript")
    pass_to_neo4j
  else
    # TODO return not found?
  end
end

get /\/webadmin.*/ do
  protected!
  pass_to_neo4j
end

get /\/db\/.*/ do
  pass_to_neo4j
end

options /\/db\/.*/ do
  pass_to_neo4j
end

post '/db/data/*' do
  protected!
  pass_to_neo4j
end

post "/db/manage/server/console/" do
  protected!
  data = JSON.parse request.body.read
  if data["engine"] == "gremlin"
    content_type "application/json"
    ["Security-Constraint: Gremlin is DISABLED", ""].to_json
  else
    pass_to_neo4j data.to_json
  end
end

post "/db/manage/server/jmx/query" do
  protected!
  pass_to_neo4j
end

def pass_to_neo4j(data=nil)
  
  request_method = request.request_method
  
  #puts "#{request_method} #{request.path}"

  request_method = request_method.downcase.to_sym

  request_headers = {
      :accept => "application/json", 
      :content_type => "application/json",
      :cookies => request.cookies
  }
  
  if request_method == :get
    proxy_response = REST[request.path].get(request_headers)
  else
    data = data || request.body.read
    proxy_response = REST[request.path].send(request_method, data, request_headers)
  end

  cookies = proxy_response.cookies
  response.set_cookie("JSESSIONID", :value => cookies["JSESSIONID"], :path => cookies["Path"]) if cookies

  content_type proxy_response.headers[:content_type]
  if %W(application/json application/x-javascript text/css text/html).include? proxy_response.headers[:content_type]
    # replace the host name of the neo4j database with the host name of the proxy so we're in the middle of future calls
    proxy_response.gsub REPLACE_DB_HOST, HEROKU_APP_HOST
  else
    proxy_response
  end
end