Add option to permit validation when schema and data are empty

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `allow_blank_structures` option #417
+  - Allow Empty Response Body. supported on Hyper-schema parser but will default to true in next major version.
+
 ## [5.2.0] - 2024-05-04
 - Error explicitly that OpenAPI 3.1+ isn't supported #418
 

README.md

@@ -28,6 +28,7 @@ This piece of middleware validates the parameters of incoming requests to make s
 
 | name | Hyper-Schema | OpenAPI 3 | Description |
 |-----------:|------------:|------------:| :------------ |
+|allow_blank_structures | false | always true | Allow Empty Response Body. supported on Hyper-schema parser but will default to true in next major version. |
 |allow_form_params | true | true | Specifies that input can alternatively be specified as `application/x-www-form-urlencoded` parameters when possible. This won't work for more complex schema validations. |
 |allow_get_body | true | false | Allow GET request body, which merge to request parameter. See (#211) |
 |allow_query_params | true | true | Specifies that query string parameters will be taken into consideration when doing validation. |

lib/committee/schema_validator/hyper_schema.rb

@@ -33,7 +33,7 @@ def response_validate(status, headers, response, _test_method = false)
           data = JSON.parse(full_body) if parse_to_json
         end
 
-        Committee::SchemaValidator::HyperSchema::ResponseValidator.new(link, validate_success_only: validator_option.validate_success_only).call(status, headers, data)
+        Committee::SchemaValidator::HyperSchema::ResponseValidator.new(link, validate_success_only: validator_option.validate_success_only, allow_blank_structures: validator_option.allow_blank_structures).call(status, headers, data)
       end
 
       def link_exist?

lib/committee/schema_validator/hyper_schema/response_validator.rb

@@ -4,11 +4,12 @@ module Committee
   module SchemaValidator
     class HyperSchema
       class ResponseValidator
-        attr_reader :validate_success_only
+        attr_reader :allow_blank_structures, :validate_success_only
 
         def initialize(link, options = {})
           @link = link
           @validate_success_only = options[:validate_success_only]
+          @allow_blank_structures = options[:allow_blank_structures]
 
           @validator = JsonSchema::Validator.new(target_schema(link))
         end
@@ -39,9 +40,18 @@ def call(status, headers, data)
             return if data == nil
           end
 
-          if Committee::Middleware::ResponseValidation.validate?(status, validate_success_only) && !@validator.validate(data)
-            errors = JsonSchema::SchemaError.aggregate(@validator.errors).join("\n")
-            raise InvalidResponse, "Invalid response.\n\n#{errors}"
+          if allow_blank_structures && @link.is_a?(Committee::Drivers::OpenAPI2::Link) && !@link.target_schema
+            return if data.nil?
+          end
+
+          begin
+            if Committee::Middleware::ResponseValidation.validate?(status, validate_success_only) && !@validator.validate(data)
+              errors = JsonSchema::SchemaError.aggregate(@validator.errors).join("\n")
+              raise InvalidResponse, "Invalid response.\n\n#{errors}"
+            end
+          rescue => e
+            raise InvalidResponse, "Invalid response.\n\nschema is undefined" if /undefined method .all_of. for nil/ =~ e.message
+            raise e
           end
         end
 

lib/committee/schema_validator/option.rb

@@ -4,7 +4,8 @@ module Committee
   module SchemaValidator
     class Option
       # Boolean Options
-      attr_reader :allow_form_params,
+      attr_reader :allow_blank_structures,
+                  :allow_form_params,
                   :allow_get_body,
                   :allow_query_params,
                   :check_content_type,
@@ -38,6 +39,7 @@ def initialize(options, schema, schema_type)
         @prefix                = options[:prefix]
 
         # Boolean options and have a common value by default
+        @allow_blank_structures           = options.fetch(:allow_blank_structures, false)
         @allow_form_params                = options.fetch(:allow_form_params, true)
         @allow_query_params               = options.fetch(:allow_query_params, true)
         @check_content_type               = options.fetch(:check_content_type, true)

test/data/openapi2/petstore-expanded.json

@@ -184,6 +184,17 @@
           }
         }
       }
+    },
+    "/pets/cat": {
+      "get": {
+        "description": "Returns pets which are cats",
+        "operationId": "find pets which are cats",
+        "responses": {
+          "200": {
+            "description": "empty schema"
+          }
+        }
+      }
     }
   },
   "definitions": {

test/middleware/response_validation_test.rb

@@ -136,6 +136,29 @@ def app
     assert_equal 200, last_response.status
   end
 
+  it "passes through a valid response for OpenAPI when data=nil, target_schema=empty, allow_blank_structures=true" do
+    @app = new_rack_app("null", {},
+                        allow_blank_structures: true, schema: open_api_2_schema)
+    get "/api/pets/cat"
+    assert_equal 200, last_response.status
+  end
+
+  it "invalid responses for OpenAPI when data=nil, target_schema=empty, allow_blank_structures=false" do
+    @app = new_rack_app("null", {},
+                        allow_blank_structures: false, schema: open_api_2_schema)
+    get "/api/pets/cat"
+    assert_equal 500, last_response.status
+    assert_match(/Invalid response/i, last_response.body)
+  end
+
+  it "passes through a valid response for OpenAPI when data=nil, target_schema=present, allow_blank_structures=true" do
+    @app = new_rack_app("null", {},
+                        allow_blank_structures: true, schema: open_api_2_schema)
+    get "/api/pets/dog"
+    assert_equal 500, last_response.status
+    assert_match(/nil is not an array/i, last_response.body)
+  end
+
   it "detects an invalid response for OpenAPI" do
     @app = new_rack_app("{_}", {}, schema: open_api_2_schema)
     get "/api/pets"