improvements to the x/errors pkg

_examples/routing/http-wire-errors/custom-validation-errors/main.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/x/errors"
+)
+
+func main() {
+	app := newApp()
+	app.Listen(":8080")
+}
+
+func newApp() *iris.Application {
+	app := iris.New()
+	app.Get("/", fireCustomValidationError)
+	app.Get("/multi", fireCustomValidationErrors)
+	app.Get("/invalid", fireInvalidError)
+	return app
+}
+
+type MyValidationError struct {
+	Field     string      `json:"field"`
+	Value     interface{} `json:"value"`
+	Reason    string      `json:"reason"`
+	Timestamp int64       `json:"timestamp"`
+}
+
+func (err MyValidationError) Error() string {
+	return fmt.Sprintf("field %q got invalid value of %v: reason: %s", err.Field, err.Value, err.Reason)
+}
+
+// Error, GetField, GetValue and GetReason completes
+// the x/errors.ValidationError interface which can be used
+// for faster rendering without the necessity of registering a custom
+// type (see at the end of the example).
+//
+// func (err MyValidationError) GetField() string {
+// 	return err.Field
+// }
+//
+// func (err MyValidationError) GetValue() interface{} {
+// 	return err.Value
+// }
+//
+// func (err MyValidationError) GetReason() string {
+// 	return err.Reason
+// }
+
+const shouldFail = true
+
+func fireCustomValidationError(ctx iris.Context) {
+	if shouldFail {
+		err := MyValidationError{
+			Field:     "username",
+			Value:     "",
+			Reason:    "empty string",
+			Timestamp: time.Now().Unix(),
+		}
+
+		// The "validation" field, when used, is always rendering as
+		// a JSON array, NOT a single object.
+		errors.InvalidArgument.Err(ctx, err)
+		return
+	}
+
+	ctx.WriteString("OK")
+}
+
+// Optionally register custom types that you may need
+// to be rendered as validation errors if the given "ErrorCodeName.Err.err"
+// input parameter is matched with one of these. Register once, at initialiation.
+func init() {
+	mapper := errors.NewValidationErrorTypeMapper(MyValidationError{} /*, OtherCustomType{} */)
+	errors.RegisterValidationErrorMapper(mapper)
+}
+
+// A custom type of the example validation error type
+// in order to complete the error interface, so it can be
+// pass through the errors.InvalidArgument.Err method.
+type MyValidationErrors []MyValidationError
+
+func (m MyValidationErrors) Error() string {
+	return "to be an error"
+}
+
+func fireCustomValidationErrors(ctx iris.Context) {
+	if shouldFail {
+		errs := MyValidationErrors{
+			{
+				Field:     "username",
+				Value:     "",
+				Reason:    "empty string",
+				Timestamp: time.Now().Unix(),
+			},
+			{
+				Field:     "birth_date",
+				Value:     "2022-01-01",
+				Reason:    "too young",
+				Timestamp: time.Now().Unix(),
+			},
+		}
+		errors.InvalidArgument.Err(ctx, errs)
+		return
+	}
+
+	ctx.WriteString("OK")
+}
+
+func fireInvalidError(ctx iris.Context) {
+	if shouldFail {
+		errors.InvalidArgument.Err(ctx, fmt.Errorf("just a custom error text"))
+		return
+	}
+
+	ctx.WriteString("OK")
+}