Delete unused photos

Make sure the models are setup so that if a photo is not used for
anything, it's removed from the system.

Also wrote a rake task (which should be run on deploy) to remove older
unused photos.

app/models/harvest.rb

@@ -10,7 +10,15 @@ class Harvest < ActiveRecord::Base
   belongs_to :plant_part
 
   has_and_belongs_to_many :photos
-  before_destroy {|harvest| harvest.photos.clear}
+
+  before_destroy do |harvest|
+    photolist = harvest.photos.to_a # save a temp copy of the photo list
+    harvest.photos.clear # clear relationship b/w harvest and photo
+
+    photolist.each do |photo|
+      photo.destroy_if_unused
+    end
+  end
 
   default_scope order('created_at DESC')
 

app/models/photo.rb

@@ -5,13 +5,20 @@ class Photo < ActiveRecord::Base
 
   has_and_belongs_to_many :plantings
   has_and_belongs_to_many :harvests
-  before_destroy do |photo| 
+  before_destroy do |photo|
     photo.plantings.clear
     photo.harvests.clear
   end
 
   default_scope order("created_at desc")
 
+  # remove photos that aren't used by anything
+  def destroy_if_unused
+    unless plantings.size > 0 and harvests.size > 0
+      self.destroy
+    end
+  end
+
   # This is split into a side-effect free method and a side-effecting method
   # for easier stubbing and testing.
   def flickr_metadata

app/models/planting.rb

@@ -11,7 +11,15 @@ class Planting < ActiveRecord::Base
   belongs_to :crop, :counter_cache => true
 
   has_and_belongs_to_many :photos
-  before_destroy {|planting| planting.photos.clear}
+
+  before_destroy do |planting|
+    photolist = planting.photos.to_a # save a temp copy of the photo list
+    planting.photos.clear # clear relationship b/w planting and photo
+
+    photolist.each do |photo|
+      photo.destroy_if_unused
+    end
+  end
 
   default_scope order("created_at desc")
   scope :finished, where(:finished => true)

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20140909001730) do
+ActiveRecord::Schema.define(:version => 20140928085713) do
 
   create_table "account_types", :force => true do |t|
     t.string   "name",              :null => false
@@ -144,6 +144,7 @@ ActiveRecord::Schema.define(:version => 20140909001730) do
     t.text     "bio"
     t.integer  "plantings_count"
     t.boolean  "newsletter"
+    t.boolean  "send_planting_reminder",  :default => true
   end
 
   add_index "members", ["confirmation_token"], :name => "index_users_on_confirmation_token", :unique => true
@@ -243,6 +244,7 @@ ActiveRecord::Schema.define(:version => 20140909001730) do
     t.datetime "updated_at", :null => false
     t.string   "slug"
     t.integer  "forum_id"
+    t.integer  "parent_id"
   end
 
   add_index "posts", ["created_at", "author_id"], :name => "index_updates_on_created_at_and_user_id"

lib/tasks/growstuff.rake

@@ -249,13 +249,20 @@ namespace :growstuff do
     desc "August 2014: fix ping to pint in database"
     task :ping_to_pint => :environment do
       Harvest.find_each do |h|
-        if h.unit == "ping" 
+        if h.unit == "ping"
           h.unit = "pint"
           h.save
         end
       end
     end
 
+    desc "October 2014: remove unused photos"
+    task :remove_unused_photos => :environment do
+      Photo.find_each do |p|
+        p.destroy_if_unused
+      end
+    end
+
   end # end oneoff section
 
 end

spec/models/photo_spec.rb

@@ -2,6 +2,82 @@ require 'spec_helper'
 
 describe Photo do
 
+  describe 'add/delete functionality' do
+    let(:photo) { FactoryGirl.create(:photo) }
+    let(:planting) { FactoryGirl.create(:planting) }
+    let(:harvest) { FactoryGirl.create(:harvest) }
+
+    context "adds photos" do
+      it 'to a planting' do
+        planting.photos << photo
+        expect(planting.photos.count).to eq 1
+        expect(planting.photos.first).to eq photo
+      end
+
+      it 'to a harvest' do
+        harvest.photos << photo
+        expect(harvest.photos.count).to eq 1
+        expect(harvest.photos.first).to eq photo
+      end
+    end
+
+    context "removing photos" do
+      it 'from a planting' do
+        planting.photos << photo
+        photo.destroy
+        expect(planting.photos.count).to eq 0
+      end
+
+      it 'from a harvest' do
+        harvest.photos << photo
+        photo.destroy
+        expect(harvest.photos.count).to eq 0
+      end
+
+      it "automatically if unused" do
+        photo.destroy_if_unused
+        expect(lambda { photo.reload }).to raise_error ActiveRecord::RecordNotFound
+      end
+
+      it 'they are no longer used by plantings' do
+        planting.photos << photo
+        planting.destroy # photo is now no longer used by anything
+        expect(lambda { photo.reload }).to raise_error ActiveRecord::RecordNotFound
+      end
+
+      it 'they are no longer used by harvests' do
+        harvest.photos << photo
+        harvest.destroy # photo is now no longer used by anything
+        expect(lambda { photo.reload }).to raise_error ActiveRecord::RecordNotFound
+      end
+
+      it 'they are no longer used by anything' do
+        planting.photos << photo
+        harvest.photos << photo
+        expect(photo.plantings.size).to eq 1
+        expect(photo.harvests.size).to eq 1
+
+        planting.destroy # photo is still used by harvest
+        photo.reload
+        expect(photo).to be_an_instance_of Photo
+        expect(photo.plantings.size).to eq 0
+        expect(photo.harvests.size).to eq 1
+
+        harvest.destroy # photo is now no longer used by anything
+        expect(lambda { photo.reload }).to raise_error ActiveRecord::RecordNotFound
+      end
+
+      it 'does not occur when a photo is still in use' do
+        planting.photos << photo
+        harvest.photos << photo
+        planting.destroy # photo is still used by the harvest
+        expect(photo).to be_an_instance_of Photo
+      end
+
+    end # removing photos
+
+  end # add/delete functionality
+
   describe 'flickr_metadata' do
     # Any further tests led to us MOCKING ALL THE THINGS
     # which was epistemologically unsatisfactory.