Enhance PURL error handling in package lookup to manage invalid formats

app/controllers/api/v1/packages_controller.rb

@@ -58,11 +58,21 @@ def lookup
     # if packages are not found, try to sync them
     if @packages.empty?
       if params[:purl].present?
-        purl = PackageURL.parse(params[:purl])
-        name = [purl.namespace, purl.name].compact.join(Ecosystem::Base.purl_type_to_namespace_seperator(purl.type))
-        ecosystem = Ecosystem::Base.purl_type_to_ecosystem(purl.type) 
-        registry = Registry.find_by_ecosystem(ecosystem)
-        registry.sync_package_async(name) if registry
+        begin
+          purl = PackageURL.parse(params[:purl])
+          name = [purl.namespace, purl.name].compact.join(Ecosystem::Base.purl_type_to_namespace_seperator(purl.type))
+          ecosystem = Ecosystem::Base.purl_type_to_ecosystem(purl.type)
+          registry = Registry.find_by_ecosystem(ecosystem)
+          registry.sync_package_async(name) if registry
+        rescue ArgumentError => e
+          Rails.logger.error("ArgumentError in PURL parsing: #{e.message}")
+          if e.message.include?("type is required")
+            render json: { error: "Invalid PURL format (type is required): #{params[:purl]}" }, status: :unprocessable_entity and return
+          elsif e.message.downcase.include?('invalid')
+            render json: { error: "Invalid PURL format: #{params[:purl]}" }, status: :unprocessable_entity and return
+          end
+          raise e
+        end
       elsif params[:ecosystem].present? && params[:name].present?
         registry = Registry.find_by_ecosystem(params[:ecosystem])
         registry.sync_package_async(params[:name]) if registry

test/controllers/api/v1/packages_controller_test.rb

@@ -59,6 +59,17 @@ class ApiV1PackagesControllerTest < ActionDispatch::IntegrationTest
     assert_equal actual_response.first['name'], @package.name
   end
 
+  test 'lookup by purl with missing type' do
+    invalid_purl = 'pkg:/software.amazon.awssdk%3Ametrics-spi'
+
+    get lookup_api_v1_packages_path(purl: invalid_purl)
+
+    assert_response :unprocessable_entity
+    actual_response = Oj.load(@response.body)
+
+    assert_equal 'Invalid PURL format (type is required): pkg:/software.amazon.awssdk%3Ametrics-spi', actual_response['error']
+  end
+
   test 'lookup by purl github actions' do
     @registry = Registry.create(name: 'github actions', url: 'https://github.com/marketplace/actions/', ecosystem: 'actions')
     @package = @registry.packages.create(ecosystem: 'actions', name: 'actions/checkout')