Resolve OpenAPI 2 parameter references

lib/committee/drivers/open_api_2/driver.rb

@@ -127,6 +127,20 @@ def parse_definitions!(data)
           [schema, store]
         end
 
+        def resolve_parameter_references(link_data, data)
+          return link_data unless link_data["parameters"]
+
+          parameters = link_data["parameters"].map do |parameter|
+            ref = parameter["$ref"]
+            next parameter unless ref
+
+            name = ref.delete_prefix("#/parameters/").gsub("~1", "/").gsub("~0", "~")
+            data.fetch("parameters").fetch(name)
+          end
+
+          link_data.merge("parameters" => parameters)
+        end
+
         def parse_routes!(data, schema, store)
           routes = {}
 
@@ -152,6 +166,7 @@ def parse_routes!(data, schema, store)
               link.href = href
               link.media_type = schema.produces
               link.method = method
+              link_data = resolve_parameter_references(link_data, data)
 
               # Convert the spec's parameter pseudo-schemas into JSON schemas that
               # we can use for some basic request validation.

test/drivers/open_api_2/driver_test.rb

@@ -44,6 +44,19 @@
     end
   end
 
+  it "resolves references to reusable parameters" do
+    schema_data = schema_data_with_responses({ '200' => { 'description' => 'ok' } })
+    schema_data['parameters'] = { 'limit' => { 'name' => 'limit', 'in' => 'query', 'type' => 'integer' }, 'authorization' => { 'name' => 'Authorization', 'in' => 'header', 'type' => 'string' }, }
+    schema_data['paths']['/foos']['get']['parameters'] = [{ '$ref' => '#/parameters/limit' }, { '$ref' => '#/parameters/authorization' },]
+
+    schema = @driver.parse(schema_data)
+
+    link = schema.routes['GET'][0][1]
+    assert_equal ['limit'], link.schema.properties.keys
+    assert_equal ['integer'], link.schema.properties['limit'].type
+    assert_equal ['Authorization'], link.header_schema.properties.keys
+  end
+
   it "names capture groups into href regexes" do
     schema = @driver.parse(open_api_2_data)
     assert_equal %r{^\/api\/pets\/(?<id>[^\/]+)$}.inspect, schema.routes["DELETE"][0][0].inspect