Adds error handling midleware

dispatcher.go

@@ -21,6 +21,14 @@ type RequestHandler interface {
 // RequestMiddlewere is interface for request middleweres
 type RequestMiddlewere func(next RequestHandler) RequestHandler
 
+// RequestHandlerFunc is a function that implements RequestHandler interface
+type RequestHandlerFunc func(conn Connection, req Request) error
+
+// Handle implements RequestHandler interface
+func (f RequestHandlerFunc) Handle(conn Connection, req Request) error {
+	return f(conn, req)
+}
+
 // NewPipeDispatcher creates new instance of PipeDispatcher
 func NewPipeDispatcher(backend Backend) *PipeDispatcher {
 	return &PipeDispatcher{backend: backend}

middleware/request/error_handler.go

@@ -0,0 +1,19 @@
+package request
+
+import "github.com/ksysoev/wasabi"
+
+type ErrorHandler func(conn wasabi.Connection, req wasabi.Request, err error) error
+
+func NewErrorHandlingMiddleware(onError ErrorHandler) func(next wasabi.RequestHandler) wasabi.RequestHandler {
+	return func(next wasabi.RequestHandler) wasabi.RequestHandler {
+		return wasabi.RequestHandlerFunc(func(conn wasabi.Connection, req wasabi.Request) error {
+			err := next.Handle(conn, req)
+
+			if err != nil {
+				return onError(conn, req, err)
+			}
+
+			return nil
+		})
+	}
+}