Init: lab4 done

middlewares/errorHandler.go

@@ -0,0 +1,56 @@
+package middlewares
+
+import (
+	"net/http"
+
+	"github.com/uptrace/bunrouter"
+	"go.uber.org/zap"
+)
+
+type HTTPError struct {
+	StatusCode  int    `json:"code"`
+	Message     string `json:"message"`
+	OriginError error  `json:"-"`
+}
+
+func (e HTTPError) Error() string {
+	return e.Message
+}
+
+func NewHTTPError(err error) HTTPError {
+	return HTTPError{
+		StatusCode:  http.StatusInternalServerError,
+		Message:     "Internal server error with unknown reason",
+		OriginError: err,
+	}
+}
+
+func ErrorHandler(next bunrouter.HandlerFunc) bunrouter.HandlerFunc {
+	return func(w http.ResponseWriter, req bunrouter.Request) error {
+		err := next(w, req)
+
+		var httpErr HTTPError
+		switch err := err.(type) {
+		case nil:
+			return nil
+
+		case HTTPError:
+			httpErr = err
+
+		default:
+			httpErr = NewHTTPError(err)
+		}
+
+		if httpErr.OriginError == nil {
+			zap.L().Warn(httpErr.Message)
+		} else {
+			zap.L().Warn(httpErr.Message,
+				zap.Error(httpErr.OriginError))
+		}
+
+		w.WriteHeader(httpErr.StatusCode)
+		_ = bunrouter.JSON(w, httpErr)
+
+		return err
+	}
+}