feat: add bcp 47 language tag validator (#730)

baked_in.go

@@ -18,6 +18,7 @@ import (
 	"unicode/utf8"
 
 	"golang.org/x/crypto/sha3"
+	"golang.org/x/text/language"
 
 	urn "github.com/leodido/go-urn"
 )
@@ -188,6 +189,7 @@ var (
 		"iso3166_1_alpha2":        isIso3166Alpha2,
 		"iso3166_1_alpha3":        isIso3166Alpha3,
 		"iso3166_1_alpha_numeric": isIso3166AlphaNumeric,
+		"bcp47_language_tag":      isBCP47LanguageTag,
 	}
 )
 
@@ -2286,3 +2288,15 @@ func isIso3166AlphaNumeric(fl FieldLevel) bool {
 	}
 	return iso3166_1_alpha_numeric[code]
 }
+
+// isBCP47LanguageTag is the validation function for validating if the current field's value is a valid BCP 47 language tag, as parsed by language.Parse
+func isBCP47LanguageTag(fl FieldLevel) bool {
+	field := fl.Field()
+
+	if field.Kind() == reflect.String {
+		_, err := language.Parse(field.String())
+		return err == nil
+	}
+
+	panic(fmt.Sprintf("Bad field type %T", field.Interface()))
+}

doc.go

@@ -1221,6 +1221,13 @@ see: https://www.iso.org/iso-3166-country-codes.html
 
 	Usage: iso3166_1_alpha3
 
+BCP 47 Language Tag
+
+This validates that a string value is a valid BCP 47 language tag, as parsed by language.Parse.
+More information on https://pkg.go.dev/golang.org/x/text/language
+
+	Usage: bcp47_language_tag
+
 TimeZone
 
 This validates that a string value is a valid time zone based on the time zone database present on the system.

go.mod

@@ -8,4 +8,5 @@ require (
 	github.com/go-playground/universal-translator v0.17.0
 	github.com/leodido/go-urn v1.2.0
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
+	golang.org/x/text v0.3.2 // indirect
 )

go.sum

@@ -10,17 +10,22 @@ github.com/leodido/go-urn v1.2.0 h1:hpXL4XnriNwQ/ABnpepYM/1vCLWNDfUNts8dX3xTG6Y=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 h1:psW17arqaxU48Z5kZ0CQnkZWQJsqcURM6tKiBApRjXI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

validator_test.go

@@ -11158,3 +11158,46 @@ func TestDurationType(t *testing.T) {
 		})
 	}
 }
+
+func TestBCP47LanguageTagValidation(t *testing.T) {
+	tests := []struct {
+		value    string `validate:"bcp47_language_tag"`
+		tag      string
+		expected bool
+	}{
+		{"en-US", "bcp47_language_tag", true},
+		{"en_GB", "bcp47_language_tag", true},
+		{"es", "bcp47_language_tag", true},
+		{"English", "bcp47_language_tag", false},
+		{"ESES", "bcp47_language_tag", false},
+		{"az-Cyrl-AZ", "bcp47_language_tag", true},
+		{"en-029", "bcp47_language_tag", true},
+		{"xog", "bcp47_language_tag", true},
+	}
+
+	validate := New()
+
+	for i, test := range tests {
+
+		errs := validate.Var(test.value, test.tag)
+
+		if test.expected {
+			if !IsEqual(errs, nil) {
+				t.Fatalf("Index: %d locale failed Error: %s", i, errs)
+			}
+		} else {
+			if IsEqual(errs, nil) {
+				t.Fatalf("Index: %d locale failed Error: %s", i, errs)
+			} else {
+				val := getError(errs, "", "")
+				if val.Tag() != "bcp47_language_tag" {
+					t.Fatalf("Index: %d locale failed Error: %s", i, errs)
+				}
+			}
+		}
+	}
+
+	PanicMatches(t, func() {
+		_ = validate.Var(2, "bcp47_language_tag")
+	}, "Bad field type int")
+}