Download inputs as a csv with min, max, default, unit and user value

app/controllers/api/v3/inputs_controller.rb

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+require 'csv'
 
 module Api
   module V3
@@ -10,18 +11,19 @@ class InputsController < ::Api::V3::BaseController
 
       # GET /api/v3/inputs
       # GET /api/v3/scenarios/:scenario_id/inputs
+      # GET /api/v3/scenarios/:scenario_id/inputs.csv
       #
-      # Returns the details for all available inputs. If the scenario_id isn't
-      # passed then the action will use the latest scenario.
-      #
+      # Returns input details in JSON or CSV format. Uses the latest scenario if
+      # scenario_id is not provided.
+
       def index
         extras = ActiveModel::Type::Boolean.new.cast(params[:include_extras])
+        inputs = serialized_inputs(extras)
 
-        render json: InputSerializer.collection(
-          Input.all,
-          @scenario,
-          **serializer_args(extra_attributes: extras)
-        )
+        respond_to do |format|
+          format.json { render json: inputs }
+          format.csv { send_csv_data(inputs) }
+        end
       end
 
       # GET /api/v3/inputs/:id
@@ -77,6 +79,53 @@ def serializer_args(extra_attributes:)
           extra_attributes:
         }
       end
+
+      def serialized_inputs(extras)
+        InputSerializer.collection(
+          Input.all,
+          @scenario,
+          **serializer_args(extra_attributes: extras)
+        )
+      end
+
+      def send_csv_data(inputs)
+        csv_data = generate_csv(inputs)
+        send_data csv_data, filename: "inputs_#{@scenario.id}.csv"
+      end
+
+      def generate_csv(inputs)
+        CSV.generate(headers: true) do |csv|
+          csv << csv_headers
+          cached_values = Input.cache(@scenario.parent)
+          user_values = @scenario.user_values
+
+          inputs.each do |key, input|
+            add_csv_row(csv, key, input, cached_values, user_values)
+          end
+        end
+      end
+
+      def csv_headers
+        ["Key", "Min", "Max", "Default", "User Value", "Unit", "Share Group"]
+      end
+
+      def add_csv_row(csv, key, input, cached_values, user_values)
+        input_data = input.instance_variable_get(:@input)
+        return if input_data.nil?
+
+        values = cached_values.read(@scenario.parent, input_data)
+        default_value = input.instance_variable_get(:@default_values_from).call(values)
+
+        csv << [
+          key,
+          input_data.min_value,
+          input_data.max_value,
+          default_value,
+          user_values[input_data.key] || "",
+          input_data.unit,
+          input_data.share_group
+        ]
+      end
     end
   end
 end

config/routes.rb

@@ -85,7 +85,7 @@
         get 'converters', to: redirect('/api/v3/scenarios/%{scenario_id}/nodes')
         get 'converters/:id', to: redirect('/api/v3/scenarios/%{scenario_id}/nodes/%{id}')
 
-        resources :inputs, :only => [:index, :show]
+        resources :inputs, :only => [:index, :show], defaults: { format: :json}
 
         resource :version, :only => [:create, :show, :update], controller: 'scenario_version_tags'
 

spec/controllers/api/v3/inputs_controller_spec.rb

@@ -7,27 +7,29 @@
     FactoryBot.build(:input, {
       min_value:    5,
       max_value:   15,
-      start_value: 10
+      start_value: 10,
+      unit:        'kWh'
     })
   end
 
   let(:gql_input) do
     FactoryBot.build(:input, {
       start_value_gql: 'present:2 * 4',
       min_value_gql:   'present:2 * 2',
-      max_value_gql:   'present:2 * 8'
+      max_value_gql:   'present:2 * 8',
+      unit:            'MW'
     })
   end
 
   before do
     NastyCache.instance.expire!
-    allow(Input).to receive(:all).and_return([ static_input, gql_input ])
+    allow(Input).to receive(:all).and_return([static_input, gql_input])
   end
 
   # --------------------------------------------------------------------------
 
-  describe 'GET /api/v3/scenarios/:scenario_id/inputs' do
-    let(:json) { JSON.parse(get(:index, params: { scenario_id: scenario.id }).body) }
+  describe 'GET /api/v3/scenarios/:scenario_id/inputs (JSON format)' do
+    let(:json) { JSON.parse(get(:index, params: { scenario_id: scenario.id, format: :json }).body) }
 
     it 'is successful' do
       json
@@ -174,7 +176,8 @@
       end
 
       let(:json) do
-        JSON.parse(get(:index, params: { scenario_id: scenario.id, defaults: 'parent' }).body)
+        response = get(:index, params: { scenario_id: scenario.id, defaults: 'parent', format: :json })
+        JSON.parse(response.body)
       end
 
       it 'has a "default" attribute for each input based on the parent' do
@@ -192,7 +195,7 @@
       end
 
       let(:json) do
-        JSON.parse(get(:index, params: { scenario_id: scenario.id, defaults: 'original' }).body)
+        JSON.parse(get(:index, params: { scenario_id: scenario.id, defaults: 'original', format: :json }).body)
       end
 
       it 'has a "default" attribute for each input based on the dataset' do
@@ -211,7 +214,7 @@
        gql_input.key    => gql_input
      })
 
-     get(:show, params: { scenario_id: scenario.id, id: static_input.key })
+     get(:show, params: { scenario_id: scenario.id, id: static_input.key, format: :json })
      JSON.parse(response.body)
    end
 
@@ -303,5 +306,4 @@
      expect(json.any? { |v| v['code'] == gql_input.key }).to be_falsey
    end
  end # GET /api/v3/scenarios/:scenario_id/inputs
-
 end