Merge pull request #684 from maco/standard_weights

Standard weights for harvests

Gemfile

@@ -31,6 +31,7 @@ gem 'figaro'                       # for handling config via ENV variables
 gem 'cancancan', '~> 1.9'          # for checking member privileges
 gem 'gibbon'                       # for Mailchimp newsletter subscriptions
 gem 'csv_shaper'                   # CSV export
+gem 'ruby-units'                   # for unit conversion
 
 # vendored activemerchant for testing- needed for bogus paypal
 # gateway monkeypatch

Gemfile.lock

@@ -292,6 +292,7 @@ GEM
       rspec-mocks (~> 3.1.0)
       rspec-support (~> 3.1.0)
     rspec-support (3.1.2)
+    ruby-units (1.4.5)
     ruby_parser (3.1.3)
       sexp_processor (~> 4.1)
     sass (3.2.19)
@@ -408,6 +409,7 @@ DEPENDENCIES
   rake (>= 10.0.0)
   rspec-activemodel-mocks
   rspec-rails (~> 3.1.0)
+  ruby-units
   sass-rails (~> 4.0.4)
   therubyracer (~> 0.12)
   uglifier (~> 2.5.3)

app/controllers/harvests_controller.rb

@@ -107,6 +107,6 @@ class HarvestsController < ApplicationController
 
   def harvest_params
     params.require(:harvest).permit(:crop_id, :harvested_at, :description, :owner_id,
-    :quantity, :unit, :weight_quantity, :weight_unit, :plant_part_id, :slug)
+    :quantity, :unit, :weight_quantity, :weight_unit, :plant_part_id, :slug, :si_weight)
   end
 end

app/models/harvest.rb

@@ -59,6 +59,17 @@ class Harvest < ActiveRecord::Base
 
   after_validation :cleanup_quantities
 
+  before_save :set_si_weight
+
+  # we're storing the harvest weight in kilograms in the db too 
+  # to make data manipulation easier
+  def set_si_weight
+    if self.weight_unit != nil
+      weight_string = "#{self.weight_quantity} #{self.weight_unit}"
+      self.si_weight = Unit(weight_string).convert_to("kg").to_s("%0.3f").delete(" kg").to_f
+    end
+  end
+
   def cleanup_quantities
     if quantity == 0
       self.quantity = nil

app/views/harvests/index.csv.shaper

@@ -10,6 +10,7 @@ csv.headers :id,
   :unit,
   :weight_quantity,
   :weight_unit,
+  :si_weight,
   :date_harvested,
   :description,
   :date_added,
@@ -31,7 +32,7 @@ csv.headers :id,
     csv.cell :plant_part_id, h.plant_part ? h.plant_part.id : ''
     csv.cell :plant_part_name, h.plant_part ? h.plant_part.to_s : ''
 
-    csv.cells :quantity, :unit, :weight_quantity, :weight_unit
+    csv.cells :quantity, :unit, :weight_quantity, :weight_unit, :si_weight
 
     csv.cell :date_harvested, h.created_at.to_s(:db)
 

db/migrate/20150129034206_add_si_weight_to_harvest.rb

@@ -0,0 +1,5 @@
+class AddSiWeightToHarvest < ActiveRecord::Migration
+  def change
+    add_column :harvests, :si_weight, :float
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150127043022) do
+ActiveRecord::Schema.define(version: 20150129034206) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -139,6 +139,7 @@ ActiveRecord::Schema.define(version: 20150127043022) do
     t.decimal  "weight_quantity"
     t.string   "weight_unit"
     t.integer  "plant_part_id"
+    t.float    "si_weight"
   end
 
   create_table "harvests_photos", id: false, force: true do |t|

lib/tasks/growstuff.rake

@@ -315,6 +315,13 @@ namespace :growstuff do
       end
     end
 
+    desc "January 2015: fill in si_weight column"
+    task :populate_si_weight => :environment do
+      Harvest.find_each do |h|
+        h.set_si_weight
+      end
+    end
+
     desc "January 2015: build Elasticsearch index"
     task :elasticsearch_create_index => :environment do
       Crop.__elasticsearch__.create_index! force: true

script/deploy-tasks.sh

@@ -19,7 +19,8 @@ rake growstuff:import_crops file=db/seeds/crops-15-squashes.csv
 echo "2014-12-01 - load alternate names for crops"
 rake growstuff:oneoff:add_alternate_names
 
+echo "2015-01-28 - populate the harvest si_weight field"
+rake growstuff:oneoff:populate_si_weight
+
 echo "2015-01-30 - build Elasticsearch index"
 rake growstuff:oneoff:elasticsearch_create_index
-
-

spec/models/harvest_spec.rb

@@ -118,6 +118,26 @@ describe Harvest do
     end
   end
 
+  context "standardized weights" do
+    it 'converts from pounds' do
+      @harvest = FactoryGirl.create(:harvest, :weight_quantity => 2, :weight_unit => "lb")
+      @harvest.should be_valid
+      @harvest.reload.si_weight.should eq 0.907
+    end
+
+    it 'converts from ounces' do
+      @harvest = FactoryGirl.create(:harvest, :weight_quantity => 16, :weight_unit => "oz")
+      @harvest.should be_valid
+      @harvest.reload.si_weight.should eq 0.454
+    end
+
+    it 'leaves kg alone' do
+      @harvest = FactoryGirl.create(:harvest, :weight_quantity => 2, :weight_unit => "kg")
+      @harvest.should be_valid
+      @harvest.reload.si_weight.should eq 2.0
+    end
+  end
+
   context 'ordering' do
     it 'lists most recent harvests first' do
       @h1 = FactoryGirl.create(:harvest, :created_at => 1.day.ago)