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

Author: joshuaslate

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

@@ -1221,14 +1221,21 @@ 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.
 Although empty value and Local value are allowed by time.LoadLocation golang function, they are not allowed by this validator.
 More information on https://golang.org/pkg/time/#LoadLocation
 
 	Usage: timezone
-  
+
 
 Alias Validators and Tags
 

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")
+}