adding all code to retrieve (and destroy) tags for a city; includes tags_service config and after_destroy hooks on a city

Author: Tim Schmelmer

app/models/city.rb

@@ -9,7 +9,21 @@ class City < ActiveRecord::Base
   validates_numericality_of :latitude, allow_nil: true
   validates_numericality_of :longitude, allow_nil: true
 
+  after_destroy :destroy_remote_tags
+
+  def tags(refresh = false)
+    @tags = RemoteTag.find_by_city_ids([id]) if refresh || !@tags
+    @tags
+  end
+
   def geocode_string
     "#{name}_#{state}_#{country}"
   end
+
+  private
+
+  def destroy_remote_tags
+    RemoteTag.destroy_tags_for_city(id, tags.map(&:name))
+  end
+
 end

app/models/remote_tag.rb

@@ -0,0 +1,56 @@
+class RemoteTag
+  class << self
+    attr_accessor :host, :api_version, :max_concurrency
+
+    def max_concurrency
+      @max_concurrency ||= 1
+    end
+
+    def api_version
+      @api_version ||= '2'
+    end
+
+    def find_by_name(name)
+      raise "RemoteTag.host needs to be set" unless host
+      Hashie::Mash.new(
+          JSON.parse(Typhoeus.get("#{host}/api/v#{api_version}/tags/#{name}?item_type=city").body)
+        )
+    end
+
+    def find_by_city_ids(ids)
+      return [] unless ids.size > 0
+      raise "RemoteTag.host needs to be set" unless host
+      requests = []
+      ids.each do |id|
+        requests << Typhoeus::Request.new("#{host}/api/v#{api_version}/tags?item_id=#{id}&item_type=city", followlocation: true)
+      end
+      requests.each { |r| hydra.queue(r) }
+      hydra.run
+      requests.keep_if{ |req| req.response.success? }
+      requests.map {|req| JSON.parse(req.response.body)}.flatten(1).map {|hsh| Hashie::Mash.new(hsh)}
+    end
+
+    def destroy_tags_for_city (city_id, tag_names = [])
+      return false unless city_id
+      return true if tag_names && tag_names.size == 0
+      raise "RemoteTag.host needs to be set" unless host
+
+      requests = []
+      tag_names.each do |tag_name|
+        requests << Typhoeus::Request.new("#{host}/api/v#{api_version}/tags/#{tag_name}/tagged_items/#{city_id}?item_type=city", method: :delete, followlocation: true)
+      end
+      requests.each { |r| hydra.queue(r) }
+      hydra.run
+      requests.keep_if{ |req| req.response.code == 204 }
+      return requests.size > 0
+    end
+
+    private
+    def hydra
+      @hydra ||= begin
+        Typhoeus::Config.memoize = true
+        Typhoeus::Hydra.new(max_concurrency: max_concurrency)
+      end
+    end
+  end
+end

app/presenters/v1/city_presenter.rb

@@ -2,21 +2,22 @@ class Presenters::V1::CityPresenter < ::Presenter
 
   attr_accessor :city
 
-  def initialize(item)
-    @city = item
+  def initialize(city)
+    @city = city
     super(@city)
   end
 
-  def to_hash(item = city)
+  def to_hash(ct = city)
     HashWithIndifferentAccess.new(
     {
-      id:           city.id,
-      name:         city.name,
-      state:        city.state,
-      country_name: city.country,
-      latitude:     city.latitude,
-      longitude:    city.longitude,
-      path:         city_path(self.class.version_number, city.id)
+      id:           ct.id,
+      name:         ct.name,
+      state:        ct.state,
+      country_name: ct.country,
+      latitude:     ct.latitude,
+      longitude:    ct.longitude,
+      path:         city_path(self.class.version_number, ct.id),
+      tags:         ct.tags.map(&:name)
     })
   end
 end

config/initializers/tags_service.rb

@@ -0,0 +1,5 @@
+config = YAML.load(File.read("#{Rails.root}/config/tags_service.yml"))[Rails.env]
+
+RemoteTag.host = config['port'] ? "#{config['host']}:#{config['port']}" : "#{config['host']}"
+RemoteTag.api_version = "#{config['api_version'] || '2'}"
+RemoteTag.max_concurrency = config['max_concurrency'] || 1

config/tags_service.yml

@@ -0,0 +1,16 @@
+development:
+  host: tags-service-development.herokuapp.com
+  port: 80
+  api_version: 2
+  max_concurrency: 4
+
+test:
+  host: tags-service-development.herokuapp.com
+  port: 80
+  api_version: 2
+
+production:
+  host: tags-service-development.herokuapp.com
+  port: 80
+  api_version: 2
+  max_concurrency: 10