Publish price as in new DFC standard

engines/dfc_provider/app/services/offer_builder.rb

@@ -7,10 +7,17 @@ class OfferBuilder < DfcBuilder
       id: variant.id,
     )
 
+    price = DataFoodConsortium::Connector::Price.new(
+      value: variant.price.to_f,
+
+      # The DFC measures define only five currencies at the moment.
+      # And they are not standardised enough to align with our ISO 4217
+      # currency codes. So I propose to just use those currency codes instead.
+      # https://github.com/datafoodconsortium/taxonomies/issues/48
+      unit: "dfc-m:#{variant.currency}",
+    )
     DataFoodConsortium::Connector::Offer.new(
-      id,
-      price: variant.price.to_f,
-      stockLimitation: stock_limitation(variant),
+      id, price:, stockLimitation: stock_limitation(variant),
     )
   end
 

engines/dfc_provider/spec/services/offer_builder_spec.rb

@@ -3,7 +3,7 @@
 require_relative "../spec_helper"
 
 RSpec.describe OfferBuilder do
-  let(:variant) { build(:variant) }
+  let(:variant) { build(:variant, id: 5) }
 
   describe ".offer" do
     it "assigns a stock level" do
@@ -26,5 +26,14 @@ RSpec.describe OfferBuilder do
 
       expect(offer.stockLimitation).to eq nil
     end
+
+    it "assigns a price with currency" do
+      variant.id = 5
+
+      offer = OfferBuilder.build(variant)
+
+      expect(offer.price.value).to eq 19.99
+      expect(offer.price.unit).to eq "dfc-m:AUD"
+    end
   end
 end

swagger/dfc.yaml

@@ -181,7 +181,10 @@ paths:
                       ofn:spree_product_uri: http://test.host/api/dfc/enterprises/10000?spree_product_id=90000
                     - "@id": http://test.host/api/dfc/enterprises/10000/offers/10001
                       "@type": dfc-b:Offer
-                      dfc-b:hasPrice: 19.99
+                      dfc-b:hasPrice:
+                        "@type": dfc-b:Price
+                        dfc-b:value: 19.99
+                        dfc-b:hasUnit: dfc-m:AUD
                       dfc-b:stockLimitation: 0
         '401':
           description: unauthorized
@@ -219,7 +222,10 @@ paths:
                       dfc-b:offeredThrough: http://test.host/api/dfc/enterprises/10000/offers/10001
                     - "@id": http://test.host/api/dfc/enterprises/10000/offers/10001
                       "@type": dfc-b:Offer
-                      dfc-b:hasPrice: 19.99
+                      dfc-b:hasPrice:
+                        "@type": dfc-b:Price
+                        dfc-b:value: 19.99
+                        dfc-b:hasUnit: dfc-m:AUD
                       dfc-b:stockLimitation: 0
         '404':
           description: not found
@@ -499,7 +505,10 @@ paths:
                     "@context": https://www.datafoodconsortium.org
                     "@id": http://test.host/api/dfc/enterprises/10000/offers/10001
                     "@type": dfc-b:Offer
-                    dfc-b:hasPrice: 19.99
+                    dfc-b:hasPrice:
+                      "@type": dfc-b:Price
+                      dfc-b:value: 19.99
+                      dfc-b:hasUnit: dfc-m:AUD
                     dfc-b:stockLimitation: 5
     put:
       summary: Update Offer