Refactors binding module

binding/validate.go

@@ -0,0 +1,79 @@
+// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package binding
+
+import (
+	"errors"
+	"reflect"
+	"strings"
+)
+
+func Validate(obj interface{}) error {
+	return validate(obj, "{{ROOT}}")
+}
+
+func validate(obj interface{}, parent string) error {
+	typ, val := inspectObject(obj)
+	switch typ.Kind() {
+	case reflect.Struct:
+		return validateStruct(typ, val, parent)
+
+	case reflect.Slice:
+		return validateSlice(typ, val, parent)
+
+	default:
+		return errors.New("The object is not a slice or struct.")
+	}
+}
+
+func inspectObject(obj interface{}) (typ reflect.Type, val reflect.Value) {
+	typ = reflect.TypeOf(obj)
+	val = reflect.ValueOf(obj)
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+		val = val.Elem()
+	}
+	return
+}
+
+func validateSlice(typ reflect.Type, val reflect.Value, parent string) error {
+	if typ.Elem().Kind() == reflect.Struct {
+		for i := 0; i < val.Len(); i++ {
+			itemValue := val.Index(i).Interface()
+			if err := validate(itemValue, parent); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func validateStruct(typ reflect.Type, val reflect.Value, parent string) error {
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		// Allow ignored and unexported fields in the struct
+		// TODO should include  || field.Tag.Get("form") == "-"
+		if len(field.PkgPath) > 0 {
+			continue
+		}
+
+		fieldValue := val.Field(i).Interface()
+		requiredField := strings.Index(field.Tag.Get("binding"), "required") > -1
+
+		if requiredField {
+			zero := reflect.Zero(field.Type).Interface()
+			if reflect.DeepEqual(zero, fieldValue) {
+				return errors.New("Required " + field.Name + " in " + parent)
+			}
+		}
+		fieldType := field.Type.Kind()
+		if fieldType == reflect.Struct || fieldType == reflect.Slice {
+			if err := validate(fieldValue, field.Name); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}