protoc-gen-swagger: support JSON Schema Validation properties and add…

… openapiv2_field option

This change supports [JSON Schema Validation](https://tools.ietf.org/html/draft-fge-json-schema-validation-00) properties.
It allows you to specify some validation rules in `openapiv2_schema` option and `openapiv2_field` option of your .proto files.

examples/clients/abe/examplepb_a_bit_of_everything.go

@@ -19,7 +19,7 @@ type ExamplepbABitOfEverything struct {
 
 	SingleNested ABitOfEverythingNested `json:"single_nested,omitempty"`
 
-	Uuid string `json:"uuid,omitempty"`
+	Uuid string `json:"uuid"`
 
 	Nested []ABitOfEverythingNested `json:"nested,omitempty"`
 

examples/proto/examplepb/a_bit_of_everything.proto

@@ -132,6 +132,7 @@ message ABitOfEverything {
 		json_schema: {
 			title: "A bit of everything"
 			description: "Intentionaly complicated message type to cover many features of Protobuf."
+			required: ["uuid"]
 		}
 		external_docs: {
 			url: "https://github.com/grpc-ecosystem/grpc-gateway";
@@ -155,7 +156,7 @@ message ABitOfEverything {
 	}
 	Nested single_nested = 25;
 
-	string uuid = 1;
+	string uuid = 1 [(grpc.gateway.protoc_gen_swagger.options.openapiv2_field) = {pattern: "[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}"}];
 	repeated Nested nested = 2;
 	float float_value = 3;
 	double double_value = 4;

examples/proto/examplepb/a_bit_of_everything.swagger.json

@@ -1001,7 +1001,8 @@
           "$ref": "#/definitions/ABitOfEverythingNested"
         },
         "uuid": {
-          "type": "string"
+          "type": "string",
+          "pattern": "[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}"
         },
         "nested": {
           "type": "array",
@@ -1121,7 +1122,10 @@
       "externalDocs": {
         "description": "Find out more about ABitOfEverything",
         "url": "https://github.com/grpc-ecosystem/grpc-gateway"
-      }
+      },
+      "required": [
+        "uuid"
+      ]
     },
     "examplepbBody": {
       "type": "object",

protoc-gen-swagger/genswagger/template.go

@@ -251,6 +251,20 @@ func renderMessagesAsDefinition(messages messageMap, d swaggerDefinitionsObject,
 
 			// Warning: Make sure not to overwrite any fields already set on the schema type.
 			schema.ExternalDocs = protoSchema.ExternalDocs
+			schema.MultipleOf = protoSchema.MultipleOf
+			schema.Maximum = protoSchema.Maximum
+			schema.ExclusiveMaximum = protoSchema.ExclusiveMaximum
+			schema.Minimum = protoSchema.Minimum
+			schema.ExclusiveMinimum = protoSchema.ExclusiveMinimum
+			schema.MaxLength = protoSchema.MaxLength
+			schema.MinLength = protoSchema.MinLength
+			schema.Pattern = protoSchema.Pattern
+			schema.MaxItems = protoSchema.MaxItems
+			schema.MinItems = protoSchema.MinItems
+			schema.UniqueItems = protoSchema.UniqueItems
+			schema.MaxProperties = protoSchema.MaxProperties
+			schema.MinProperties = protoSchema.MinProperties
+			schema.Required = protoSchema.Required
 			if protoSchema.schemaCore.Type != "" || protoSchema.schemaCore.Ref != "" {
 				schema.schemaCore = protoSchema.schemaCore
 			}
@@ -318,6 +332,7 @@ func schemaOfField(f *descriptor.Field, reg *descriptor.Registry, refs refMap) s
 			core = schemaCore{Type: ft.String(), Format: "UNKNOWN"}
 		}
 	}
+
 	switch aggregate {
 	case array:
 		return swaggerSchemaObject{
@@ -334,7 +349,13 @@ func schemaOfField(f *descriptor.Field, reg *descriptor.Registry, refs refMap) s
 			AdditionalProperties: &swaggerSchemaObject{schemaCore: core},
 		}
 	default:
-		return swaggerSchemaObject{schemaCore: core}
+		ret := swaggerSchemaObject{
+			schemaCore: core,
+		}
+		if j, err := extractJSONSchemaFromFieldDescriptor(fd); err == nil {
+			updateSwaggerObjectFromJSONSchema(&ret, j)
+		}
+		return ret
 	}
 }
 
@@ -1263,28 +1284,73 @@ func extractSwaggerOptionFromFileDescriptor(file *pbdescriptor.FileDescriptorPro
 	return opts, nil
 }
 
-func swaggerSchemaFromProtoSchema(s *swagger_options.Schema, reg *descriptor.Registry, refs refMap) swaggerSchemaObject {
-	ret := swaggerSchemaObject{
-		ExternalDocs: protoExternalDocumentationToSwaggerExternalDocumentation(s.GetExternalDocs()),
-		Title:        s.GetJsonSchema().GetTitle(),
-		Description:  s.GetJsonSchema().GetDescription(),
-		// TODO(johanbrandhorst): Add more fields?
+func extractJSONSchemaFromFieldDescriptor(fd *pbdescriptor.FieldDescriptorProto) (*swagger_options.JSONSchema, error) {
+	if fd.Options == nil {
+		return nil, nil
 	}
-	if s.GetJsonSchema().GetRef() != "" {
-		swaggerName := fullyQualifiedNameToSwaggerName(s.GetJsonSchema().GetRef(), reg)
+	if !proto.HasExtension(fd.Options, swagger_options.E_Openapiv2Field) {
+		return nil, nil
+	}
+	ext, err := proto.GetExtension(fd.Options, swagger_options.E_Openapiv2Field)
+	if err != nil {
+		return nil, err
+	}
+	opts, ok := ext.(*swagger_options.JSONSchema)
+	if !ok {
+		return nil, fmt.Errorf("extension is %T; want a JSONSchema object", ext)
+	}
+	return opts, nil
+}
+
+func protoJSONSchemaToSwaggerSchemaCore(j *swagger_options.JSONSchema, reg *descriptor.Registry, refs refMap) schemaCore {
+	ret := schemaCore{}
+
+	if j.GetRef() != "" {
+		swaggerName := fullyQualifiedNameToSwaggerName(j.GetRef(), reg)
 		if swaggerName != "" {
-			ret.schemaCore.Ref = "#/definitions/" + swaggerName
+			ret.Ref = "#/definitions/" + swaggerName
 			if refs != nil {
-				refs[s.GetJsonSchema().GetRef()] = struct{}{}
+				refs[j.GetRef()] = struct{}{}
 			}
 		} else {
-			ret.schemaCore.Ref += s.GetJsonSchema().GetRef()
+			ret.Ref += j.GetRef()
 		}
 	} else {
-		f, t := protoJSONSchemaTypeToFormat(s.GetJsonSchema().GetType())
-		ret.schemaCore.Format = f
-		ret.schemaCore.Type = t
+		f, t := protoJSONSchemaTypeToFormat(j.GetType())
+		ret.Format = f
+		ret.Type = t
 	}
+
+	return ret
+}
+
+func updateSwaggerObjectFromJSONSchema(s *swaggerSchemaObject, j *swagger_options.JSONSchema) {
+	s.Title = j.GetTitle()
+	s.Description = j.GetDescription()
+	s.MultipleOf = j.GetMultipleOf()
+	s.Maximum = j.GetMaximum()
+	s.ExclusiveMaximum = j.GetExclusiveMaximum()
+	s.Minimum = j.GetMinimum()
+	s.ExclusiveMinimum = j.GetExclusiveMinimum()
+	s.MaxLength = j.GetMaxLength()
+	s.MinLength = j.GetMinLength()
+	s.Pattern = j.GetPattern()
+	s.MaxItems = j.GetMaxItems()
+	s.MinItems = j.GetMinItems()
+	s.UniqueItems = j.GetUniqueItems()
+	s.MaxProperties = j.GetMaxProperties()
+	s.MinProperties = j.GetMinProperties()
+	s.Required = j.GetRequired()
+}
+
+func swaggerSchemaFromProtoSchema(s *swagger_options.Schema, reg *descriptor.Registry, refs refMap) swaggerSchemaObject {
+	ret := swaggerSchemaObject{
+		ExternalDocs: protoExternalDocumentationToSwaggerExternalDocumentation(s.GetExternalDocs()),
+	}
+
+	ret.schemaCore = protoJSONSchemaToSwaggerSchemaCore(s.GetJsonSchema(), reg, refs)
+	updateSwaggerObjectFromJSONSchema(&ret, s.GetJsonSchema())
+
 	return ret
 }
 

protoc-gen-swagger/genswagger/types.go

@@ -204,6 +204,21 @@ type swaggerSchemaObject struct {
 	Title       string `json:"title,omitempty"`
 
 	ExternalDocs *swaggerExternalDocumentationObject `json:"externalDocs,omitempty"`
+
+	MultipleOf       float64  `json:"multiple_of,omitempty"`
+	Maximum          float64  `json:"maximum,omitempty"`
+	ExclusiveMaximum bool     `json:"exclusive_maximum,omitempty"`
+	Minimum          float64  `json:"minimum,omitempty"`
+	ExclusiveMinimum bool     `json:"exclusive_minimum,omitempty"`
+	MaxLength        uint64   `json:"max_length,omitempty"`
+	MinLength        uint64   `json:"min_length,omitempty"`
+	Pattern          string   `json:"pattern,omitempty"`
+	MaxItems         uint64   `json:"max_items,omitempty"`
+	MinItems         uint64   `json:"min_items,omitempty"`
+	UniqueItems      bool     `json:"unique_items,omitempty"`
+	MaxProperties    uint64   `json:"max_properties,omitempty"`
+	MinProperties    uint64   `json:"min_properties,omitempty"`
+	Required         []string `json:"required,omitempty"`
 }
 
 // http://swagger.io/specification/#referenceObject

protoc-gen-swagger/options/annotations.proto

@@ -35,3 +35,10 @@ extend google.protobuf.ServiceOptions {
   // different descriptor messages.
   Tag openapiv2_tag = 1042;
 }
+extend google.protobuf.FieldOptions {
+  // ID assigned by [email protected] for grpc-gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  JSONSchema openapiv2_field = 1042;
+}