1 // Copyright 2016 Qiang Xue. All rights reserved.
2 // Use of this source code is governed by a MIT-style
3 // license that can be found in the LICENSE file.
4 5 package validation
6 7 var (
8 // ErrRequired is the error that returns when a value is required.
9 ErrRequired = NewError("validation_required", "cannot be blank")
10 // ErrNilOrNotEmpty is the error that returns when a value is not nil and is empty.
11 ErrNilOrNotEmpty = NewError("validation_nil_or_not_empty_required", "cannot be blank")
12 )
13 14 // Required is a validation rule that checks if a value is not empty.
15 // A value is considered not empty if
16 // - integer, float: not zero
17 // - bool: true
18 // - string, array, slice, map: len() > 0
19 // - interface, pointer: not nil and the referenced value is not empty
20 // - any other types
21 var Required = RequiredRule{skipNil: false, condition: true}
22 23 // NilOrNotEmpty checks if a value is a nil pointer or a value that is not empty.
24 // NilOrNotEmpty differs from Required in that it treats a nil pointer as valid.
25 var NilOrNotEmpty = RequiredRule{skipNil: true, condition: true}
26 27 // RequiredRule is a rule that checks if a value is not empty.
28 type RequiredRule struct {
29 condition bool
30 skipNil bool
31 err Error
32 }
33 34 // Validate checks if the given value is valid or not.
35 func (r RequiredRule) Validate(value interface{}) error {
36 if r.condition {
37 value, isNil := Indirect(value)
38 if r.skipNil && !isNil && IsEmpty(value) || !r.skipNil && (isNil || IsEmpty(value)) {
39 if r.err != nil {
40 return r.err
41 }
42 if r.skipNil {
43 return ErrNilOrNotEmpty
44 }
45 return ErrRequired
46 }
47 }
48 return nil
49 }
50 51 // When sets the condition that determines if the validation should be performed.
52 func (r RequiredRule) When(condition bool) RequiredRule {
53 r.condition = condition
54 return r
55 }
56 57 // Error sets the error message for the rule.
58 func (r RequiredRule) Error(message string) RequiredRule {
59 if r.err == nil {
60 if r.skipNil {
61 r.err = ErrNilOrNotEmpty
62 } else {
63 r.err = ErrRequired
64 }
65 }
66 r.err = r.err.SetMessage(message)
67 return r
68 }
69 70 // ErrorObject sets the error struct for the rule.
71 func (r RequiredRule) ErrorObject(err Error) RequiredRule {
72 r.err = err
73 return r
74 }
75