schema/field: add rune length validators for string fields (#4398)

Signed-off-by: liangminhua <ben302010@live.cn>

schema/field/field.go

@@ -15,6 +15,7 @@ import (
 	"regexp"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"entgo.io/ent/schema"
 )
@@ -222,6 +223,18 @@ func (b *stringBuilder) MinLen(i int) *stringBuilder {
 	return b
 }
 
+// MinRuneLen adds a rune length validator for this field.
+// Operation fails if the rune count of the string is less than the given value.
+func (b *stringBuilder) MinRuneLen(i int) *stringBuilder {
+	b.desc.Validators = append(b.desc.Validators, func(v string) error {
+		if utf8.RuneCountInString(v) < i {
+			return errors.New("value is less than the required rune length")
+		}
+		return nil
+	})
+	return b
+}
+
 // NotEmpty adds a length validator for this field.
 // Operation fails if the length of the string is zero.
 func (b *stringBuilder) NotEmpty() *stringBuilder {
@@ -241,6 +254,19 @@ func (b *stringBuilder) MaxLen(i int) *stringBuilder {
 	return b
 }
 
+// MaxRuneLen adds a rune length validator for this field.
+// Operation fails if the rune count of the string is greater than the given value.
+func (b *stringBuilder) MaxRuneLen(i int) *stringBuilder {
+	b.desc.Size = i
+	b.desc.Validators = append(b.desc.Validators, func(v string) error {
+		if utf8.RuneCountInString(v) > i {
+			return errors.New("value is greater than the required rune length")
+		}
+		return nil
+	})
+	return b
+}
+
 // Validate adds a validator for this field. Operation fails if the validation fails.
 func (b *stringBuilder) Validate(fn func(string) error) *stringBuilder {
 	b.desc.Validators = append(b.desc.Validators, fn)

schema/field/field_test.go

@@ -975,3 +975,43 @@ func TestTypeConstName(t *testing.T) {
 	typ = 21
 	assert.Equal(t, "invalid", typ.ConstName())
 }
+
+func TestString_MinRuneLen(t *testing.T) {
+	fd := field.String("name").MinRuneLen(5).Descriptor()
+	assert.Len(t, fd.Validators, 1)
+
+	err := fd.Validators[0].(func(string) error)("hello")
+	assert.NoError(t, err)
+
+	err = fd.Validators[0].(func(string) error)("hi")
+	assert.EqualError(t, err, "value is less than the required rune length")
+
+	err = fd.Validators[0].(func(string) error)("你好")
+	assert.EqualError(t, err, "value is less than the required rune length")
+
+	err = fd.Validators[0].(func(string) error)("你好世界！")
+	assert.NoError(t, err)
+
+	err = fd.Validators[0].(func(string) error)("")
+	assert.Error(t, err)
+}
+
+func TestString_MaxRuneLen(t *testing.T) {
+	fd := field.String("name").MaxRuneLen(5).Descriptor()
+	assert.Len(t, fd.Validators, 1)
+
+	err := fd.Validators[0].(func(string) error)("hello")
+	assert.NoError(t, err)
+
+	err = fd.Validators[0].(func(string) error)("hello world")
+	assert.EqualError(t, err, "value is greater than the required rune length")
+
+	err = fd.Validators[0].(func(string) error)("你好世界你好")
+	assert.EqualError(t, err, "value is greater than the required rune length")
+
+	err = fd.Validators[0].(func(string) error)("你好世界！")
+	assert.NoError(t, err)
+
+	err = fd.Validators[0].(func(string) error)("")
+	assert.NoError(t, err)
+}