Module: Arcgis::Model

Defined in:
lib/arcgis/model.rb

Overview

Acts as a builder for classes based on routes.rb. This should be considered private. All entry points to models should come through connection.

Constant Summary collapse

@@classes = 
{}

Class Method Summary collapse

Class Method Details

.build(connection:, type:, id: nil) ⇒ Object

Sole entry point into the module–looks up the appropriate class by type (e.g. item, group, etc.) and initializes an instance of it



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# File 'lib/arcgis/model.rb', line 14

def build(connection:, type:, id: nil)
  class_for_type(type).new(connection, id)
end

.class_for_type(type) ⇒ Object

Returns a copy of a class to handle the appropriate object type, creating the class if needed



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# File 'lib/arcgis/model.rb', line 23

def class_for_type(type)
  @@classes[type] ||= Class.new do
    def initialize(connection, id)
      @connection, @id = connection, id
    end


    #
    # Helper method to extract HTTP method, argument names, the the path.
    # e.g. "POST /content/users/:username/items/:id/delete" becomes
    # {method: "POST", args: ["username", "id"],
    #    path: "/content/users/:username/items/:id/delete"}
    #
    def extract_config(path_config)
      method, path_pattern = path_config.split(' ')
      args = path_pattern.scan(/\/:[^\/]+/)
      arg_names = args.map{|a| a[2..-1]}
      return { method: method, args: arg_names, path: path_pattern }
    end


    #
    # Args to be merged into every path
    #
    def default_args
      {id: @id, username: @connection.username}
    end


    # Helper procs
    stringify_keys = ->(x) { x.reduce({}){|h, (k,v)| h[k.to_s] = v; h} }
    symbolize_keys = ->(x) { x.reduce({}){|h, (k,v)| h[k.to_s.to_sym] = v; h} }

    Arcgis::Routes::ROUTES[type].each_pair do |meth, path_config|
      #
      # Creates the specific path for a request, merging default_args with
      # user-provided arguments, to create a final path.
      # e.g. for item: delete: "POST /content/users/:username/items/:id/delete"
      # substitutes in :username and :id to get something like
      # {method: "POST",
      #  path: "/content/users/someuser/items/4e770315ad9049e7950b552aa1e40869/delete"}
      #
      self.send(:define_method, "#{meth}_path") do |local_args = {}|
        # stringify keys
        local_args = stringify_keys[local_args]

        config = self.extract_config(path_config)
        args = stringify_keys[self.default_args.merge(local_args)]

        path = config[:args].reduce(config[:path]) do |u,arg|
          u.sub("/:#{arg}", "/#{args[arg]}")
        end

        {method: config[:method], path: path}
      end


      #
      # Creates a method for each route in the routes file that merges in
      # variables (see #{meth}_path) and then runs the request via the
      # connection
      #
      self.send(:define_method, "#{meth}") do |local_args = {}|
        local_args = symbolize_keys[local_args]
        path_args = send("#{meth}_path")
        args = (path_args[:method] == "GET") ?
          path_args.merge(params: stringify_keys[local_args]) :
          path_args.merge(body: stringify_keys[local_args])

        @connection.run(args)
      end
    end
  end
end