Serve .mbtiles with Rack

mb_tiles.rb

require File.expand_path('../../../config/application', __FILE__)

require 'rack'
require 'sqlite3'

module Rack
  class MbTiles
    attr_reader :app
    
    def initialize(app)
      @app = app
    end
    
    def dbpath
     # path to db.mbtiles here
    end
  
    def call(env)    
      return app.call(env) unless env['PATH_INFO'].match(/mbtiles/)
      options  = env['PATH_INFO'].match(/mbtiles\/(.*)\/(.*)\/(.*).png$/i)
      zoom, column, y = options[1], options[2], options[3]
      puts dbpath.inspect
      database = ::SQLite3::Database.new(dbpath)
      rows     = database.execute("select images.tile_data from map inner join images 
                                  on (map.tile_id = images.tile_id) where zoom_level = #{zoom} AND tile_row = #{y} AND tile_column = #{column}")
      unless rows.empty?
        [200, {"Content-Type" => "image/png"}, [rows[0][0]]]
      else
        [404, {}, [""]]
      end
    end
  end
  
end