feat: use generics in handlers

ChristophBe · Dec 23, 2023 · 6112c96 · 6112c96
1 parent 18d5e80
commit 6112c96
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Showing 19 changed files with 272 additions and 209 deletions.
diff --git a/go.mod b/go.mod
@@ -1,3 +1,3 @@
 module github.com/ChristophBe/grud
 
-go 1.15
+go 1.18
diff --git a/handlers/create.go b/handlers/create.go
@@ -5,8 +5,8 @@ import (
 	"net/http"
 )
 
-// NewCreatHandler creates a http.Handler that handles the creation of a model
-func NewCreatHandler(service types.CreateService, responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
+// NewCreateHandler creates a http.Handler that handles the creation of a model
+func NewCreateHandler[Model any](service types.CreateService[Model], responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
 		ctx := request.Context()
 		dto, err := service.ParseDtoFromRequest(request)
@@ -20,13 +20,14 @@ func NewCreatHandler(service types.CreateService, responseWriter types.ResponseW
 			return
 		}
 
-		model, err := dto.AssignToModel(ctx, service.CreateEmptyModel(ctx))
+		var model Model
+		model, err = dto.AssignToModel(ctx, model)
 		if err != nil {
 			errorWriter(err, writer, request)
 			return
 		}
 
-		if model, err = model.Create(ctx); err != nil {
+		if model, err = service.CreateModel(ctx, model); err != nil {
 			errorWriter(err, writer, request)
 			return
 		}

diff --git a/handlers/create_test.go b/handlers/create_test.go
@@ -9,12 +9,15 @@ import (
 	"testing"
 )
 
+type testModel struct {
+	Value string
+}
 type parseDtoFromRequestServiceMock struct {
-	dto types.Dto
+	dto types.Dto[testModel]
 	err error
 }
 
-func (p parseDtoFromRequestServiceMock) ParseDtoFromRequest(_ *http.Request) (types.Dto, error) {
+func (p parseDtoFromRequestServiceMock) ParseDtoFromRequest(_ *http.Request) (types.Dto[testModel], error) {
 	return p.dto, p.err
 }
 
@@ -26,21 +29,34 @@ func (c createEmptyModelServiceMock) CreateEmptyModel(_ context.Context) types.M
 	return c.emptyModel
 }
 
+type createModelServiceMock struct {
+	createdModel testModel
+	err          error
+}
+
+func (c createModelServiceMock) CreateModel(_ context.Context, _ testModel) (testModel, error) {
+	return c.createdModel, c.err
+}
+
 type createServiceMock struct {
-	createEmptyModelServiceMock
+	createModelServiceMock
 	parseDtoFromRequestServiceMock
 }
 
 func TestCrudHandlersImpl_Create(t *testing.T) {
 
 	expectedResponseStatus := http.StatusAccepted
 
+	validModel := testModel{
+		Value: "value",
+	}
+
 	tt := []struct {
 		name                string
-		service             types.CreateService
+		service             types.CreateService[testModel]
 		responseWriterError error
 		expectedError       error
-		resultModel         modelMock
+		resultModel         testModel
 	}{
 		{
 			name: "parse dto form request turns error",
@@ -55,7 +71,7 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 			name: "dto is invalid",
 			service: createServiceMock{
 				parseDtoFromRequestServiceMock: parseDtoFromRequestServiceMock{
-					dto: dtoMock{
+					dto: dtoMock[testModel]{
 						validationError: errors.New("test"),
 					},
 				},
@@ -66,8 +82,8 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 			name: "dto assign to model failed",
 			service: createServiceMock{
 				parseDtoFromRequestServiceMock: parseDtoFromRequestServiceMock{
-					dto: dtoMock{
-						assignModelResult: modelErrorHolder{
+					dto: dtoMock[testModel]{
+						assignModelResult: modelErrorHolder[testModel]{
 							err: errors.New("test"),
 						},
 					},
@@ -79,32 +95,25 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 			name: "model save model failed",
 			service: createServiceMock{
 				parseDtoFromRequestServiceMock: parseDtoFromRequestServiceMock{
-					dto: dtoMock{
-						assignModelResult: modelErrorHolder{
-							model: modelMock{
-								createResult: modelErrorHolder{
-									err: errors.New("test"),
-								},
-							},
+					dto: dtoMock[testModel]{
+						assignModelResult: modelErrorHolder[testModel]{
+							model: testModel{Value: "test"},
 						},
 					},
 				},
+				createModelServiceMock: createModelServiceMock{
+					err: errors.New("test"),
+				},
 			},
 			expectedError: errors.New("test"),
 		},
 		{
 			name: "response writer returns error",
 			service: createServiceMock{
 				parseDtoFromRequestServiceMock: parseDtoFromRequestServiceMock{
-					dto: dtoMock{
-						assignModelResult: modelErrorHolder{
-							model: modelMock{
-								createResult: modelErrorHolder{
-									model: modelMock{
-										value: "test-value",
-									},
-								},
-							},
+					dto: dtoMock[testModel]{
+						assignModelResult: modelErrorHolder[testModel]{
+							model: validModel,
 						},
 					},
 				},
@@ -116,23 +125,18 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 			name: "success",
 			service: createServiceMock{
 				parseDtoFromRequestServiceMock: parseDtoFromRequestServiceMock{
-					dto: dtoMock{
-						assignModelResult: modelErrorHolder{
-							model: modelMock{
-								createResult: modelErrorHolder{
-									model: modelMock{
-										value: "test-value",
-									},
-								},
-							},
+					dto: dtoMock[testModel]{
+						assignModelResult: modelErrorHolder[testModel]{
+							model: validModel,
 						},
 					},
 				},
+				createModelServiceMock: createModelServiceMock{
+					createdModel: validModel,
+				},
 			},
 			expectedError: nil,
-			resultModel: modelMock{
-				value: "test-value",
-			},
+			resultModel:   validModel,
 		},
 	}
 
@@ -146,7 +150,7 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 
 			errorWriter := newMockErrorWriter(errorRecorder)
 
-			handler := NewCreatHandler(tc.service, responseWriter, errorWriter)
+			handler := NewCreateHandler[testModel](tc.service, responseWriter, errorWriter)
 			w := httptest.ResponseRecorder{}
 			handler.ServeHTTP(&w, new(http.Request))
 
@@ -168,13 +172,13 @@ func TestCrudHandlersImpl_Create(t *testing.T) {
 				if responseRecorder.status != expectedResponseStatus {
 					t.Errorf("expected response status to be %v, got %v", expectedResponseStatus, responseRecorder.status)
 				}
-				result, ok := responseRecorder.body.(modelMock)
+				result, ok := responseRecorder.body.(testModel)
 				if !ok {
 					t.Fatal("failed to cast model")
 				}
 
-				if tc.resultModel.value != result.value {
-					t.Errorf("expected result value to be %v, got %v", tc.resultModel.value, result.value)
+				if tc.resultModel.Value != result.Value {
+					t.Errorf("expected result value to be %v, got %v", tc.resultModel.Value, result.Value)
 				}
 
 			} else {

diff --git a/handlers/crud-handlers.go b/handlers/crud-handlers.go
@@ -16,46 +16,46 @@ type CrudHandlers interface {
 }
 
 // NewCrudHandlers creates a instance of CrudHandlers.
-func NewCrudHandlers(service types.Service, responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) CrudHandlers {
-	return crudHandlersImpl{
+func NewCrudHandlers[M types.ModelTypeInterface](service types.Service[M], responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) CrudHandlers {
+	return crudHandlersImpl[M]{
 		service:        service,
 		responseWriter: responseWriter,
 		errorWriter:    errorWriter,
 	}
 }
 
-type crudHandlersImpl struct {
-	service        types.Service
+type crudHandlersImpl[M types.ModelTypeInterface] struct {
+	service        types.Service[M]
 	responseWriter types.ResponseWriter
 	errorWriter    types.ErrorResponseWriter
 }
 
 // Create is a http.Handler that handles the creation of a model
-func (c crudHandlersImpl) Create(writer http.ResponseWriter, request *http.Request) {
-	NewCreatHandler(c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
+func (c crudHandlersImpl[M]) Create(writer http.ResponseWriter, request *http.Request) {
+	NewCreateHandler[M](c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
 }
 
 // GetAll is a http.Handler for fetch a list of model.
-func (c crudHandlersImpl) GetAll(writer http.ResponseWriter, request *http.Request) {
-	NewGetAllHandler(c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
+func (c crudHandlersImpl[M]) GetAll(writer http.ResponseWriter, request *http.Request) {
+	NewGetAllHandler[M](c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
 }
 
 // GetOne returns a http handler for handling requests one specific model.
-func (c crudHandlersImpl) GetOne(w http.ResponseWriter, r *http.Request) {
-	NewGetOneHandler(c.service, c.responseWriter, c.errorWriter)(w, r)
+func (c crudHandlersImpl[M]) GetOne(w http.ResponseWriter, r *http.Request) {
+	NewGetOneHandler[M](c.service, c.responseWriter, c.errorWriter)(w, r)
 }
 
 // Update is a http.Handler that handles partial updates for existing models.
-func (c crudHandlersImpl) Update(writer http.ResponseWriter, request *http.Request) {
-	NewUpdateHandler(c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
+func (c crudHandlersImpl[M]) Update(writer http.ResponseWriter, request *http.Request) {
+	NewUpdateHandler[M](c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
 }
 
 // Replace is a http.Handler that handles replacing an exing model.
-func (c crudHandlersImpl) Replace(writer http.ResponseWriter, request *http.Request) {
-	NewReplaceHandler(c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
+func (c crudHandlersImpl[M]) Replace(writer http.ResponseWriter, request *http.Request) {
+	NewReplaceHandler[M](c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
 }
 
 // Delete is a http handler for handling the deletion of specific model.
-func (c crudHandlersImpl) Delete(writer http.ResponseWriter, request *http.Request) {
-	NewDeleteHandler(c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
+func (c crudHandlersImpl[M]) Delete(writer http.ResponseWriter, request *http.Request) {
+	NewDeleteHandler[M](c.service, c.responseWriter, c.errorWriter).ServeHTTP(writer, request)
 }
diff --git a/handlers/delete.go b/handlers/delete.go
@@ -6,15 +6,15 @@ import (
 )
 
 // NewDeleteHandler returns a http handler for that handles the deletion of one specific model.
-func NewDeleteHandler(service types.GetOneService, responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
+func NewDeleteHandler[M types.ModelTypeInterface](service types.DeleteService[M], responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
 		model, err := service.GetOne(request)
 		if err != nil {
 			errorWriter(err, writer, request)
 			return
 		}
 
-		if err = model.Delete(request.Context()); err != nil {
+		if err = service.DeleteModel(request.Context(), model); err != nil {
 			errorWriter(err, writer, request)
 			return
 		}

diff --git a/handlers/delete_test.go b/handlers/delete_test.go
@@ -1,40 +1,64 @@
 package handlers
 
 import (
+	"context"
 	"errors"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 )
 
+type deleteMockServiceMock struct {
+	deletionError error
+}
+
+func (d deleteMockServiceMock) DeleteModel(_ context.Context, _ testModel) error {
+	return d.deletionError
+}
+
+type deleteServiceMock struct {
+	getOneServiceMock
+	deleteMockServiceMock
+}
+
 func TestCrudHandlersImpl_Delete(t *testing.T) {
 
 	expectedResponseStatus := http.StatusNoContent
 
 	tt := []struct {
 		name string
-		getOneServiceMock
+		deleteServiceMock
 		responseWriterError error
 		expectedError       error
 	}{
 		{
 			name: "service returns error",
-			getOneServiceMock: getOneServiceMock{
-				err: errors.New("test"),
+			deleteServiceMock: deleteServiceMock{
+				getOneServiceMock: getOneServiceMock{
+					err: errors.New("test"),
+				},
 			},
 			expectedError: errors.New("test"),
 		},
 		{
-			name:                "response writer returns error",
-			getOneServiceMock:   getOneServiceMock{},
+			name: "response writer returns error",
+			deleteServiceMock: deleteServiceMock{
+				getOneServiceMock: getOneServiceMock{},
+			},
 			responseWriterError: errors.New("test-error"),
 			expectedError:       errors.New("test-error"),
 		},
 		{
 			name: "delete function returns error",
-			getOneServiceMock: getOneServiceMock{
-				model: modelMock{deleteResult: errors.New("test-error")},
+			deleteServiceMock: deleteServiceMock{
+				getOneServiceMock: getOneServiceMock{
+					model: testModel{"test-value"},
+				},
+				deleteMockServiceMock: deleteMockServiceMock{
+					deletionError: errors.New("test-error"),
+				},
 			},
+
 			expectedError: errors.New("test-error"),
 		},
 		{
@@ -53,7 +77,7 @@ func TestCrudHandlersImpl_Delete(t *testing.T) {
 
 			errorWriter := newMockErrorWriter(errorRecorder)
 
-			handler := NewDeleteHandler(tc.getOneServiceMock, responseWriter, errorWriter)
+			handler := NewDeleteHandler[testModel](tc.deleteServiceMock, responseWriter, errorWriter)
 			w := httptest.ResponseRecorder{}
 			handler.ServeHTTP(&w, new(http.Request))
 

diff --git a/handlers/function.go b/handlers/function.go
@@ -6,7 +6,7 @@ import (
 )
 
 // NewFunctionHandler creates a http.Handler that handles the creation of a model
-func NewFunctionHandler(service types.FunctionHandlerService, responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
+func NewFunctionHandler[Dto types.Validatable, Result any](service types.FunctionHandlerService[Dto, Result], responseWriter types.ResponseWriter, errorWriter types.ErrorResponseWriter) http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
 		ctx := request.Context()
 		dto, err := service.ParseValidatableFromRequest(request)