vendorify
diff --git a/go/vendor/github.com/asaskevich/govalidator/validator.go b/go/vendor/github.com/asaskevich/govalidator/validator.go
new file mode 100644
index 0000000..071f43c
--- /dev/null
+++ b/go/vendor/github.com/asaskevich/govalidator/validator.go
@@ -0,0 +1,1213 @@
+// Package govalidator is package of validators and sanitizers for strings, structs and collections.
+package govalidator
+
+import (
+	"bytes"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/url"
+	"reflect"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+	"unicode"
+	"unicode/utf8"
+)
+
+var (
+	fieldsRequiredByDefault bool
+	notNumberRegexp         = regexp.MustCompile("[^0-9]+")
+	whiteSpacesAndMinus     = regexp.MustCompile("[\\s-]+")
+	paramsRegexp            = regexp.MustCompile("\\(.*\\)$")
+)
+
+const maxURLRuneCount = 2083
+const minURLRuneCount = 3
+const RF3339WithoutZone = "2006-01-02T15:04:05"
+
+// SetFieldsRequiredByDefault causes validation to fail when struct fields
+// do not include validations or are not explicitly marked as exempt (using `valid:"-"` or `valid:"email,optional"`).
+// This struct definition will fail govalidator.ValidateStruct() (and the field values do not matter):
+//     type exampleStruct struct {
+//         Name  string ``
+//         Email string `valid:"email"`
+// This, however, will only fail when Email is empty or an invalid email address:
+//     type exampleStruct2 struct {
+//         Name  string `valid:"-"`
+//         Email string `valid:"email"`
+// Lastly, this will only fail when Email is an invalid email address but not when it's empty:
+//     type exampleStruct2 struct {
+//         Name  string `valid:"-"`
+//         Email string `valid:"email,optional"`
+func SetFieldsRequiredByDefault(value bool) {
+	fieldsRequiredByDefault = value
+}
+
+// IsEmail check if the string is an email.
+func IsEmail(email string) bool {
+	if len(email) < 6 || len(email) > 254 {
+		return false
+	}
+	at := strings.LastIndex(email, "@")
+	if at <= 0 || at > len(email)-3 {
+		return false
+	}
+	user := email[:at]
+	host := email[at+1:]
+	if len(user) > 64 {
+		return false
+	}
+	if userDotRegexp.MatchString(user) || !userRegexp.MatchString(user) || !hostRegexp.MatchString(host) {
+		return false
+	}
+	switch host {
+	case "localhost", "example.com":
+		return true
+	}
+	if _, err := net.LookupMX(host); err != nil {
+		if _, err := net.LookupIP(host); err != nil {
+			return false
+		}
+	}
+
+	return true
+}
+
+// IsURL check if the string is an URL.
+func IsURL(str string) bool {
+	if str == "" || utf8.RuneCountInString(str) >= maxURLRuneCount || len(str) <= minURLRuneCount || strings.HasPrefix(str, ".") {
+		return false
+	}
+	strTemp := str
+	if strings.Index(str, ":") >= 0 && strings.Index(str, "://") == -1 {
+		// support no indicated urlscheme but with colon for port number
+		// http:// is appended so url.Parse will succeed, strTemp used so it does not impact rxURL.MatchString
+		strTemp = "http://" + str
+	}
+	u, err := url.Parse(strTemp)
+	if err != nil {
+		return false
+	}
+	if strings.HasPrefix(u.Host, ".") {
+		return false
+	}
+	if u.Host == "" && (u.Path != "" && !strings.Contains(u.Path, ".")) {
+		return false
+	}
+	return rxURL.MatchString(str)
+}
+
+// IsRequestURL check if the string rawurl, assuming
+// it was received in an HTTP request, is a valid
+// URL confirm to RFC 3986
+func IsRequestURL(rawurl string) bool {
+	url, err := url.ParseRequestURI(rawurl)
+	if err != nil {
+		return false //Couldn't even parse the rawurl
+	}
+	if len(url.Scheme) == 0 {
+		return false //No Scheme found
+	}
+	return true
+}
+
+// IsRequestURI check if the string rawurl, assuming
+// it was received in an HTTP request, is an
+// absolute URI or an absolute path.
+func IsRequestURI(rawurl string) bool {
+	_, err := url.ParseRequestURI(rawurl)
+	return err == nil
+}
+
+// IsAlpha check if the string contains only letters (a-zA-Z). Empty string is valid.
+func IsAlpha(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxAlpha.MatchString(str)
+}
+
+//IsUTFLetter check if the string contains only unicode letter characters.
+//Similar to IsAlpha but for all languages. Empty string is valid.
+func IsUTFLetter(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+
+	for _, c := range str {
+		if !unicode.IsLetter(c) {
+			return false
+		}
+	}
+	return true
+
+}
+
+// IsAlphanumeric check if the string contains only letters and numbers. Empty string is valid.
+func IsAlphanumeric(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxAlphanumeric.MatchString(str)
+}
+
+// IsUTFLetterNumeric check if the string contains only unicode letters and numbers. Empty string is valid.
+func IsUTFLetterNumeric(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	for _, c := range str {
+		if !unicode.IsLetter(c) && !unicode.IsNumber(c) { //letters && numbers are ok
+			return false
+		}
+	}
+	return true
+
+}
+
+// IsNumeric check if the string contains only numbers. Empty string is valid.
+func IsNumeric(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxNumeric.MatchString(str)
+}
+
+// IsUTFNumeric check if the string contains only unicode numbers of any kind.
+// Numbers can be 0-9 but also Fractions ¾,Roman Ⅸ and Hangzhou 〩. Empty string is valid.
+func IsUTFNumeric(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	if strings.IndexAny(str, "+-") > 0 {
+		return false
+	}
+	if len(str) > 1 {
+		str = strings.TrimPrefix(str, "-")
+		str = strings.TrimPrefix(str, "+")
+	}
+	for _, c := range str {
+		if unicode.IsNumber(c) == false { //numbers && minus sign are ok
+			return false
+		}
+	}
+	return true
+
+}
+
+// IsUTFDigit check if the string contains only unicode radix-10 decimal digits. Empty string is valid.
+func IsUTFDigit(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	if strings.IndexAny(str, "+-") > 0 {
+		return false
+	}
+	if len(str) > 1 {
+		str = strings.TrimPrefix(str, "-")
+		str = strings.TrimPrefix(str, "+")
+	}
+	for _, c := range str {
+		if !unicode.IsDigit(c) { //digits && minus sign are ok
+			return false
+		}
+	}
+	return true
+
+}
+
+// IsHexadecimal check if the string is a hexadecimal number.
+func IsHexadecimal(str string) bool {
+	return rxHexadecimal.MatchString(str)
+}
+
+// IsHexcolor check if the string is a hexadecimal color.
+func IsHexcolor(str string) bool {
+	return rxHexcolor.MatchString(str)
+}
+
+// IsRGBcolor check if the string is a valid RGB color in form rgb(RRR, GGG, BBB).
+func IsRGBcolor(str string) bool {
+	return rxRGBcolor.MatchString(str)
+}
+
+// IsLowerCase check if the string is lowercase. Empty string is valid.
+func IsLowerCase(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return str == strings.ToLower(str)
+}
+
+// IsUpperCase check if the string is uppercase. Empty string is valid.
+func IsUpperCase(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return str == strings.ToUpper(str)
+}
+
+// HasLowerCase check if the string contains at least 1 lowercase. Empty string is valid.
+func HasLowerCase(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxHasLowerCase.MatchString(str)
+}
+
+// HasUpperCase check if the string contians as least 1 uppercase. Empty string is valid.
+func HasUpperCase(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxHasUpperCase.MatchString(str)
+}
+
+// IsInt check if the string is an integer. Empty string is valid.
+func IsInt(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxInt.MatchString(str)
+}
+
+// IsFloat check if the string is a float.
+func IsFloat(str string) bool {
+	return str != "" && rxFloat.MatchString(str)
+}
+
+// IsDivisibleBy check if the string is a number that's divisible by another.
+// If second argument is not valid integer or zero, it's return false.
+// Otherwise, if first argument is not valid integer or zero, it's return true (Invalid string converts to zero).
+func IsDivisibleBy(str, num string) bool {
+	f, _ := ToFloat(str)
+	p := int64(f)
+	q, _ := ToInt(num)
+	if q == 0 {
+		return false
+	}
+	return (p == 0) || (p%q == 0)
+}
+
+// IsNull check if the string is null.
+func IsNull(str string) bool {
+	return len(str) == 0
+}
+
+// IsByteLength check if the string's length (in bytes) falls in a range.
+func IsByteLength(str string, min, max int) bool {
+	return len(str) >= min && len(str) <= max
+}
+
+// IsUUIDv3 check if the string is a UUID version 3.
+func IsUUIDv3(str string) bool {
+	return rxUUID3.MatchString(str)
+}
+
+// IsUUIDv4 check if the string is a UUID version 4.
+func IsUUIDv4(str string) bool {
+	return rxUUID4.MatchString(str)
+}
+
+// IsUUIDv5 check if the string is a UUID version 5.
+func IsUUIDv5(str string) bool {
+	return rxUUID5.MatchString(str)
+}
+
+// IsUUID check if the string is a UUID (version 3, 4 or 5).
+func IsUUID(str string) bool {
+	return rxUUID.MatchString(str)
+}
+
+// IsCreditCard check if the string is a credit card.
+func IsCreditCard(str string) bool {
+	sanitized := notNumberRegexp.ReplaceAllString(str, "")
+	if !rxCreditCard.MatchString(sanitized) {
+		return false
+	}
+	var sum int64
+	var digit string
+	var tmpNum int64
+	var shouldDouble bool
+	for i := len(sanitized) - 1; i >= 0; i-- {
+		digit = sanitized[i:(i + 1)]
+		tmpNum, _ = ToInt(digit)
+		if shouldDouble {
+			tmpNum *= 2
+			if tmpNum >= 10 {
+				sum += ((tmpNum % 10) + 1)
+			} else {
+				sum += tmpNum
+			}
+		} else {
+			sum += tmpNum
+		}
+		shouldDouble = !shouldDouble
+	}
+
+	if sum%10 == 0 {
+		return true
+	}
+	return false
+}
+
+// IsISBN10 check if the string is an ISBN version 10.
+func IsISBN10(str string) bool {
+	return IsISBN(str, 10)
+}
+
+// IsISBN13 check if the string is an ISBN version 13.
+func IsISBN13(str string) bool {
+	return IsISBN(str, 13)
+}
+
+// IsISBN check if the string is an ISBN (version 10 or 13).
+// If version value is not equal to 10 or 13, it will be check both variants.
+func IsISBN(str string, version int) bool {
+	sanitized := whiteSpacesAndMinus.ReplaceAllString(str, "")
+	var checksum int32
+	var i int32
+	if version == 10 {
+		if !rxISBN10.MatchString(sanitized) {
+			return false
+		}
+		for i = 0; i < 9; i++ {
+			checksum += (i + 1) * int32(sanitized[i]-'0')
+		}
+		if sanitized[9] == 'X' {
+			checksum += 10 * 10
+		} else {
+			checksum += 10 * int32(sanitized[9]-'0')
+		}
+		if checksum%11 == 0 {
+			return true
+		}
+		return false
+	} else if version == 13 {
+		if !rxISBN13.MatchString(sanitized) {
+			return false
+		}
+		factor := []int32{1, 3}
+		for i = 0; i < 12; i++ {
+			checksum += factor[i%2] * int32(sanitized[i]-'0')
+		}
+		if (int32(sanitized[12]-'0'))-((10-(checksum%10))%10) == 0 {
+			return true
+		}
+		return false
+	}
+	return IsISBN(str, 10) || IsISBN(str, 13)
+}
+
+// IsJSON check if the string is valid JSON (note: uses json.Unmarshal).
+func IsJSON(str string) bool {
+	var js json.RawMessage
+	return json.Unmarshal([]byte(str), &js) == nil
+}
+
+// IsMultibyte check if the string contains one or more multibyte chars. Empty string is valid.
+func IsMultibyte(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxMultibyte.MatchString(str)
+}
+
+// IsASCII check if the string contains ASCII chars only. Empty string is valid.
+func IsASCII(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxASCII.MatchString(str)
+}
+
+// IsPrintableASCII check if the string contains printable ASCII chars only. Empty string is valid.
+func IsPrintableASCII(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxPrintableASCII.MatchString(str)
+}
+
+// IsFullWidth check if the string contains any full-width chars. Empty string is valid.
+func IsFullWidth(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxFullWidth.MatchString(str)
+}
+
+// IsHalfWidth check if the string contains any half-width chars. Empty string is valid.
+func IsHalfWidth(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxHalfWidth.MatchString(str)
+}
+
+// IsVariableWidth check if the string contains a mixture of full and half-width chars. Empty string is valid.
+func IsVariableWidth(str string) bool {
+	if IsNull(str) {
+		return true
+	}
+	return rxHalfWidth.MatchString(str) && rxFullWidth.MatchString(str)
+}
+
+// IsBase64 check if a string is base64 encoded.
+func IsBase64(str string) bool {
+	return rxBase64.MatchString(str)
+}
+
+// IsFilePath check is a string is Win or Unix file path and returns it's type.
+func IsFilePath(str string) (bool, int) {
+	if rxWinPath.MatchString(str) {
+		//check windows path limit see:
+		//  http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx#maxpath
+		if len(str[3:]) > 32767 {
+			return false, Win
+		}
+		return true, Win
+	} else if rxUnixPath.MatchString(str) {
+		return true, Unix
+	}
+	return false, Unknown
+}
+
+// IsDataURI checks if a string is base64 encoded data URI such as an image
+func IsDataURI(str string) bool {
+	dataURI := strings.Split(str, ",")
+	if !rxDataURI.MatchString(dataURI[0]) {
+		return false
+	}
+	return IsBase64(dataURI[1])
+}
+
+// IsISO3166Alpha2 checks if a string is valid two-letter country code
+func IsISO3166Alpha2(str string) bool {
+	for _, entry := range ISO3166List {
+		if str == entry.Alpha2Code {
+			return true
+		}
+	}
+	return false
+}
+
+// IsISO3166Alpha3 checks if a string is valid three-letter country code
+func IsISO3166Alpha3(str string) bool {
+	for _, entry := range ISO3166List {
+		if str == entry.Alpha3Code {
+			return true
+		}
+	}
+	return false
+}
+
+// IsISO693Alpha2 checks if a string is valid two-letter language code
+func IsISO693Alpha2(str string) bool {
+	for _, entry := range ISO693List {
+		if str == entry.Alpha2Code {
+			return true
+		}
+	}
+	return false
+}
+
+// IsISO693Alpha3b checks if a string is valid three-letter language code
+func IsISO693Alpha3b(str string) bool {
+	for _, entry := range ISO693List {
+		if str == entry.Alpha3bCode {
+			return true
+		}
+	}
+	return false
+}
+
+// IsDNSName will validate the given string as a DNS name
+func IsDNSName(str string) bool {
+	if str == "" || len(strings.Replace(str, ".", "", -1)) > 255 {
+		// constraints already violated
+		return false
+	}
+	return !IsIP(str) && rxDNSName.MatchString(str)
+}
+
+// IsHash checks if a string is a hash of type algorithm.
+// Algorithm is one of ['md4', 'md5', 'sha1', 'sha256', 'sha384', 'sha512', 'ripemd128', 'ripemd160', 'tiger128', 'tiger160', 'tiger192', 'crc32', 'crc32b']
+func IsHash(str string, algorithm string) bool {
+	len := "0"
+	algo := strings.ToLower(algorithm)
+
+	if algo == "crc32" || algo == "crc32b" {
+		len = "8"
+	} else if algo == "md5" || algo == "md4" || algo == "ripemd128" || algo == "tiger128" {
+		len = "32"
+	} else if algo == "sha1" || algo == "ripemd160" || algo == "tiger160" {
+		len = "40"
+	} else if algo == "tiger192" {
+		len = "48"
+	} else if algo == "sha256" {
+		len = "64"
+	} else if algo == "sha384" {
+		len = "96"
+	} else if algo == "sha512" {
+		len = "128"
+	} else {
+		return false
+	}
+
+	return Matches(str, "^[a-f0-9]{"+len+"}$")
+}
+
+// IsDialString validates the given string for usage with the various Dial() functions
+func IsDialString(str string) bool {
+
+	if h, p, err := net.SplitHostPort(str); err == nil && h != "" && p != "" && (IsDNSName(h) || IsIP(h)) && IsPort(p) {
+		return true
+	}
+
+	return false
+}
+
+// IsIP checks if a string is either IP version 4 or 6.
+func IsIP(str string) bool {
+	return net.ParseIP(str) != nil
+}
+
+// IsPort checks if a string represents a valid port
+func IsPort(str string) bool {
+	if i, err := strconv.Atoi(str); err == nil && i > 0 && i < 65536 {
+		return true
+	}
+	return false
+}
+
+// IsIPv4 check if the string is an IP version 4.
+func IsIPv4(str string) bool {
+	ip := net.ParseIP(str)
+	return ip != nil && strings.Contains(str, ".")
+}
+
+// IsIPv6 check if the string is an IP version 6.
+func IsIPv6(str string) bool {
+	ip := net.ParseIP(str)
+	return ip != nil && strings.Contains(str, ":")
+}
+
+// IsCIDR check if the string is an valid CIDR notiation (IPV4 & IPV6)
+func IsCIDR(str string) bool {
+	_, _, err := net.ParseCIDR(str)
+	return err == nil
+}
+
+// IsMAC check if a string is valid MAC address.
+// Possible MAC formats:
+// 01:23:45:67:89:ab
+// 01:23:45:67:89:ab:cd:ef
+// 01-23-45-67-89-ab
+// 01-23-45-67-89-ab-cd-ef
+// 0123.4567.89ab
+// 0123.4567.89ab.cdef
+func IsMAC(str string) bool {
+	_, err := net.ParseMAC(str)
+	return err == nil
+}
+
+// IsHost checks if the string is a valid IP (both v4 and v6) or a valid DNS name
+func IsHost(str string) bool {
+	return IsIP(str) || IsDNSName(str)
+}
+
+// IsMongoID check if the string is a valid hex-encoded representation of a MongoDB ObjectId.
+func IsMongoID(str string) bool {
+	return rxHexadecimal.MatchString(str) && (len(str) == 24)
+}
+
+// IsLatitude check if a string is valid latitude.
+func IsLatitude(str string) bool {
+	return rxLatitude.MatchString(str)
+}
+
+// IsLongitude check if a string is valid longitude.
+func IsLongitude(str string) bool {
+	return rxLongitude.MatchString(str)
+}
+
+// IsRsaPublicKey check if a string is valid public key with provided length
+func IsRsaPublicKey(str string, keylen int) bool {
+	bb := bytes.NewBufferString(str)
+	pemBytes, err := ioutil.ReadAll(bb)
+	if err != nil {
+		return false
+	}
+	block, _ := pem.Decode(pemBytes)
+	if block != nil && block.Type != "PUBLIC KEY" {
+		return false
+	}
+	var der []byte
+
+	if block != nil {
+		der = block.Bytes
+	} else {
+		der, err = base64.StdEncoding.DecodeString(str)
+		if err != nil {
+			return false
+		}
+	}
+
+	key, err := x509.ParsePKIXPublicKey(der)
+	if err != nil {
+		return false
+	}
+	pubkey, ok := key.(*rsa.PublicKey)
+	if !ok {
+		return false
+	}
+	bitlen := len(pubkey.N.Bytes()) * 8
+	return bitlen == int(keylen)
+}
+
+func toJSONName(tag string) string {
+	if tag == "" {
+		return ""
+	}
+
+	// JSON name always comes first. If there's no options then split[0] is
+	// JSON name, if JSON name is not set, then split[0] is an empty string.
+	split := strings.SplitN(tag, ",", 2)
+
+	name := split[0]
+
+	// However it is possible that the field is skipped when
+	// (de-)serializing from/to JSON, in which case assume that there is no
+	// tag name to use
+	if name == "-" {
+		return ""
+	}
+	return name
+}
+
+// ValidateStruct use tags for fields.
+// result will be equal to `false` if there are any errors.
+func ValidateStruct(s interface{}) (bool, error) {
+	if s == nil {
+		return true, nil
+	}
+	result := true
+	var err error
+	val := reflect.ValueOf(s)
+	if val.Kind() == reflect.Interface || val.Kind() == reflect.Ptr {
+		val = val.Elem()
+	}
+	// we only accept structs
+	if val.Kind() != reflect.Struct {
+		return false, fmt.Errorf("function only accepts structs; got %s", val.Kind())
+	}
+	var errs Errors
+	for i := 0; i < val.NumField(); i++ {
+		valueField := val.Field(i)
+		typeField := val.Type().Field(i)
+		if typeField.PkgPath != "" {
+			continue // Private field
+		}
+		structResult := true
+		if (valueField.Kind() == reflect.Struct ||
+			(valueField.Kind() == reflect.Ptr && valueField.Elem().Kind() == reflect.Struct)) &&
+			typeField.Tag.Get(tagName) != "-" {
+			var err error
+			structResult, err = ValidateStruct(valueField.Interface())
+			if err != nil {
+				errs = append(errs, err)
+			}
+		}
+		resultField, err2 := typeCheck(valueField, typeField, val, nil)
+		if err2 != nil {
+
+			// Replace structure name with JSON name if there is a tag on the variable
+			jsonTag := toJSONName(typeField.Tag.Get("json"))
+			if jsonTag != "" {
+				switch jsonError := err2.(type) {
+				case Error:
+					jsonError.Name = jsonTag
+					err2 = jsonError
+				case Errors:
+					for i2, err3 := range jsonError {
+						switch customErr := err3.(type) {
+						case Error:
+							customErr.Name = jsonTag
+							jsonError[i2] = customErr
+						}
+					}
+
+					err2 = jsonError
+				}
+			}
+
+			errs = append(errs, err2)
+		}
+		result = result && resultField && structResult
+	}
+	if len(errs) > 0 {
+		err = errs
+	}
+	return result, err
+}
+
+// parseTagIntoMap parses a struct tag `valid:required~Some error message,length(2|3)` into map[string]string{"required": "Some error message", "length(2|3)": ""}
+func parseTagIntoMap(tag string) tagOptionsMap {
+	optionsMap := make(tagOptionsMap)
+	options := strings.Split(tag, ",")
+
+	for _, option := range options {
+		option = strings.TrimSpace(option)
+
+		validationOptions := strings.Split(option, "~")
+		if !isValidTag(validationOptions[0]) {
+			continue
+		}
+		if len(validationOptions) == 2 {
+			optionsMap[validationOptions[0]] = validationOptions[1]
+		} else {
+			optionsMap[validationOptions[0]] = ""
+		}
+	}
+	return optionsMap
+}
+
+func isValidTag(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, c := range s {
+		switch {
+		case strings.ContainsRune("\\'\"!#$%&()*+-./:<=>?@[]^_{|}~ ", c):
+			// Backslash and quote chars are reserved, but
+			// otherwise any punctuation chars are allowed
+			// in a tag name.
+		default:
+			if !unicode.IsLetter(c) && !unicode.IsDigit(c) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// IsSSN will validate the given string as a U.S. Social Security Number
+func IsSSN(str string) bool {
+	if str == "" || len(str) != 11 {
+		return false
+	}
+	return rxSSN.MatchString(str)
+}
+
+// IsSemver check if string is valid semantic version
+func IsSemver(str string) bool {
+	return rxSemver.MatchString(str)
+}
+
+// IsTime check if string is valid according to given format
+func IsTime(str string, format string) bool {
+	_, err := time.Parse(format, str)
+	return err == nil
+}
+
+// IsRFC3339 check if string is valid timestamp value according to RFC3339
+func IsRFC3339(str string) bool {
+	return IsTime(str, time.RFC3339)
+}
+
+// IsRFC3339WithoutZone check if string is valid timestamp value according to RFC3339 which excludes the timezone.
+func IsRFC3339WithoutZone(str string) bool {
+	return IsTime(str, RF3339WithoutZone)
+}
+
+// IsISO4217 check if string is valid ISO currency code
+func IsISO4217(str string) bool {
+	for _, currency := range ISO4217List {
+		if str == currency {
+			return true
+		}
+	}
+
+	return false
+}
+
+// ByteLength check string's length
+func ByteLength(str string, params ...string) bool {
+	if len(params) == 2 {
+		min, _ := ToInt(params[0])
+		max, _ := ToInt(params[1])
+		return len(str) >= int(min) && len(str) <= int(max)
+	}
+
+	return false
+}
+
+// RuneLength check string's length
+// Alias for StringLength
+func RuneLength(str string, params ...string) bool {
+	return StringLength(str, params...)
+}
+
+// IsRsaPub check whether string is valid RSA key
+// Alias for IsRsaPublicKey
+func IsRsaPub(str string, params ...string) bool {
+	if len(params) == 1 {
+		len, _ := ToInt(params[0])
+		return IsRsaPublicKey(str, int(len))
+	}
+
+	return false
+}
+
+// StringMatches checks if a string matches a given pattern.
+func StringMatches(s string, params ...string) bool {
+	if len(params) == 1 {
+		pattern := params[0]
+		return Matches(s, pattern)
+	}
+	return false
+}
+
+// StringLength check string's length (including multi byte strings)
+func StringLength(str string, params ...string) bool {
+
+	if len(params) == 2 {
+		strLength := utf8.RuneCountInString(str)
+		min, _ := ToInt(params[0])
+		max, _ := ToInt(params[1])
+		return strLength >= int(min) && strLength <= int(max)
+	}
+
+	return false
+}
+
+// Range check string's length
+func Range(str string, params ...string) bool {
+	if len(params) == 2 {
+		value, _ := ToFloat(str)
+		min, _ := ToFloat(params[0])
+		max, _ := ToFloat(params[1])
+		return InRange(value, min, max)
+	}
+
+	return false
+}
+
+func isInRaw(str string, params ...string) bool {
+	if len(params) == 1 {
+		rawParams := params[0]
+
+		parsedParams := strings.Split(rawParams, "|")
+
+		return IsIn(str, parsedParams...)
+	}
+
+	return false
+}
+
+// IsIn check if string str is a member of the set of strings params
+func IsIn(str string, params ...string) bool {
+	for _, param := range params {
+		if str == param {
+			return true
+		}
+	}
+
+	return false
+}
+
+func checkRequired(v reflect.Value, t reflect.StructField, options tagOptionsMap) (bool, error) {
+	if requiredOption, isRequired := options["required"]; isRequired {
+		if len(requiredOption) > 0 {
+			return false, Error{t.Name, fmt.Errorf(requiredOption), true, "required"}
+		}
+		return false, Error{t.Name, fmt.Errorf("non zero value required"), false, "required"}
+	} else if _, isOptional := options["optional"]; fieldsRequiredByDefault && !isOptional {
+		return false, Error{t.Name, fmt.Errorf("Missing required field"), false, "required"}
+	}
+	// not required and empty is valid
+	return true, nil
+}
+
+func typeCheck(v reflect.Value, t reflect.StructField, o reflect.Value, options tagOptionsMap) (isValid bool, resultErr error) {
+	if !v.IsValid() {
+		return false, nil
+	}
+
+	tag := t.Tag.Get(tagName)
+
+	// Check if the field should be ignored
+	switch tag {
+	case "":
+		if !fieldsRequiredByDefault {
+			return true, nil
+		}
+		return false, Error{t.Name, fmt.Errorf("All fields are required to at least have one validation defined"), false, "required"}
+	case "-":
+		return true, nil
+	}
+
+	isRootType := false
+	if options == nil {
+		isRootType = true
+		options = parseTagIntoMap(tag)
+	}
+
+	if isEmptyValue(v) {
+		// an empty value is not validated, check only required
+		return checkRequired(v, t, options)
+	}
+
+	var customTypeErrors Errors
+	for validatorName, customErrorMessage := range options {
+		if validatefunc, ok := CustomTypeTagMap.Get(validatorName); ok {
+			delete(options, validatorName)
+
+			if result := validatefunc(v.Interface(), o.Interface()); !result {
+				if len(customErrorMessage) > 0 {
+					customTypeErrors = append(customTypeErrors, Error{Name: t.Name, Err: fmt.Errorf(customErrorMessage), CustomErrorMessageExists: true, Validator: stripParams(validatorName)})
+					continue
+				}
+				customTypeErrors = append(customTypeErrors, Error{Name: t.Name, Err: fmt.Errorf("%s does not validate as %s", fmt.Sprint(v), validatorName), CustomErrorMessageExists: false, Validator: stripParams(validatorName)})
+			}
+		}
+	}
+
+	if len(customTypeErrors.Errors()) > 0 {
+		return false, customTypeErrors
+	}
+
+	if isRootType {
+		// Ensure that we've checked the value by all specified validators before report that the value is valid
+		defer func() {
+			delete(options, "optional")
+			delete(options, "required")
+
+			if isValid && resultErr == nil && len(options) != 0 {
+				for validator := range options {
+					isValid = false
+					resultErr = Error{t.Name, fmt.Errorf(
+						"The following validator is invalid or can't be applied to the field: %q", validator), false, stripParams(validator)}
+					return
+				}
+			}
+		}()
+	}
+
+	switch v.Kind() {
+	case reflect.Bool,
+		reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
+		reflect.Float32, reflect.Float64,
+		reflect.String:
+		// for each tag option check the map of validator functions
+		for validatorSpec, customErrorMessage := range options {
+			var negate bool
+			validator := validatorSpec
+			customMsgExists := len(customErrorMessage) > 0
+
+			// Check whether the tag looks like '!something' or 'something'
+			if validator[0] == '!' {
+				validator = validator[1:]
+				negate = true
+			}
+
+			// Check for param validators
+			for key, value := range ParamTagRegexMap {
+				ps := value.FindStringSubmatch(validator)
+				if len(ps) == 0 {
+					continue
+				}
+
+				validatefunc, ok := ParamTagMap[key]
+				if !ok {
+					continue
+				}
+
+				delete(options, validatorSpec)
+
+				switch v.Kind() {
+				case reflect.String,
+					reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+					reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+					reflect.Float32, reflect.Float64:
+
+					field := fmt.Sprint(v) // make value into string, then validate with regex
+					if result := validatefunc(field, ps[1:]...); (!result && !negate) || (result && negate) {
+						if customMsgExists {
+							return false, Error{t.Name, fmt.Errorf(customErrorMessage), customMsgExists, stripParams(validatorSpec)}
+						}
+						if negate {
+							return false, Error{t.Name, fmt.Errorf("%s does validate as %s", field, validator), customMsgExists, stripParams(validatorSpec)}
+						}
+						return false, Error{t.Name, fmt.Errorf("%s does not validate as %s", field, validator), customMsgExists, stripParams(validatorSpec)}
+					}
+				default:
+					// type not yet supported, fail
+					return false, Error{t.Name, fmt.Errorf("Validator %s doesn't support kind %s", validator, v.Kind()), false, stripParams(validatorSpec)}
+				}
+			}
+
+			if validatefunc, ok := TagMap[validator]; ok {
+				delete(options, validatorSpec)
+
+				switch v.Kind() {
+				case reflect.String:
+					field := fmt.Sprint(v) // make value into string, then validate with regex
+					if result := validatefunc(field); !result && !negate || result && negate {
+						if customMsgExists {
+							return false, Error{t.Name, fmt.Errorf(customErrorMessage), customMsgExists, stripParams(validatorSpec)}
+						}
+						if negate {
+							return false, Error{t.Name, fmt.Errorf("%s does validate as %s", field, validator), customMsgExists, stripParams(validatorSpec)}
+						}
+						return false, Error{t.Name, fmt.Errorf("%s does not validate as %s", field, validator), customMsgExists, stripParams(validatorSpec)}
+					}
+				default:
+					//Not Yet Supported Types (Fail here!)
+					err := fmt.Errorf("Validator %s doesn't support kind %s for value %v", validator, v.Kind(), v)
+					return false, Error{t.Name, err, false, stripParams(validatorSpec)}
+				}
+			}
+		}
+		return true, nil
+	case reflect.Map:
+		if v.Type().Key().Kind() != reflect.String {
+			return false, &UnsupportedTypeError{v.Type()}
+		}
+		var sv stringValues
+		sv = v.MapKeys()
+		sort.Sort(sv)
+		result := true
+		for _, k := range sv {
+			var resultItem bool
+			var err error
+			if v.MapIndex(k).Kind() != reflect.Struct {
+				resultItem, err = typeCheck(v.MapIndex(k), t, o, options)
+				if err != nil {
+					return false, err
+				}
+			} else {
+				resultItem, err = ValidateStruct(v.MapIndex(k).Interface())
+				if err != nil {
+					return false, err
+				}
+			}
+			result = result && resultItem
+		}
+		return result, nil
+	case reflect.Slice, reflect.Array:
+		result := true
+		for i := 0; i < v.Len(); i++ {
+			var resultItem bool
+			var err error
+			if v.Index(i).Kind() != reflect.Struct {
+				resultItem, err = typeCheck(v.Index(i), t, o, options)
+				if err != nil {
+					return false, err
+				}
+			} else {
+				resultItem, err = ValidateStruct(v.Index(i).Interface())
+				if err != nil {
+					return false, err
+				}
+			}
+			result = result && resultItem
+		}
+		return result, nil
+	case reflect.Interface:
+		// If the value is an interface then encode its element
+		if v.IsNil() {
+			return true, nil
+		}
+		return ValidateStruct(v.Interface())
+	case reflect.Ptr:
+		// If the value is a pointer then check its element
+		if v.IsNil() {
+			return true, nil
+		}
+		return typeCheck(v.Elem(), t, o, options)
+	case reflect.Struct:
+		return ValidateStruct(v.Interface())
+	default:
+		return false, &UnsupportedTypeError{v.Type()}
+	}
+}
+
+func stripParams(validatorString string) string {
+	return paramsRegexp.ReplaceAllString(validatorString, "")
+}
+
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.String, reflect.Array:
+		return v.Len() == 0
+	case reflect.Map, reflect.Slice:
+		return v.Len() == 0 || v.IsNil()
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+
+	return reflect.DeepEqual(v.Interface(), reflect.Zero(v.Type()).Interface())
+}
+
+// ErrorByField returns error for specified field of the struct
+// validated by ValidateStruct or empty string if there are no errors
+// or this field doesn't exists or doesn't have any errors.
+func ErrorByField(e error, field string) string {
+	if e == nil {
+		return ""
+	}
+	return ErrorsByField(e)[field]
+}
+
+// ErrorsByField returns map of errors of the struct validated
+// by ValidateStruct or empty map if there are no errors.
+func ErrorsByField(e error) map[string]string {
+	m := make(map[string]string)
+	if e == nil {
+		return m
+	}
+	// prototype for ValidateStruct
+
+	switch e.(type) {
+	case Error:
+		m[e.(Error).Name] = e.(Error).Err.Error()
+	case Errors:
+		for _, item := range e.(Errors).Errors() {
+			n := ErrorsByField(item)
+			for k, v := range n {
+				m[k] = v
+			}
+		}
+	}
+
+	return m
+}
+
+// Error returns string equivalent for reflect.Type
+func (e *UnsupportedTypeError) Error() string {
+	return "validator: unsupported type: " + e.Type.String()
+}
+
+func (sv stringValues) Len() int           { return len(sv) }
+func (sv stringValues) Swap(i, j int)      { sv[i], sv[j] = sv[j], sv[i] }
+func (sv stringValues) Less(i, j int) bool { return sv.get(i) < sv.get(j) }
+func (sv stringValues) get(i int) string   { return sv[i].String() }