utils.go

package phpfuncs

import (
	"math/rand"
	"net/url"
	"regexp"
	"strings"
	"time"
	"unicode/utf8"
)

// Since only this function is needed, this control function is taken from https://github.com/asaskevich/govalidator since it is an MIT license. Thanks for MIT license Alex!

// Basic regular expressions for validating strings
const (
	maxURLRuneCount        = 2083
	minURLRuneCount        = 3
	IP              string = `(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))`
	URLSchema       string = `((ftp|tcp|udp|wss?|https?):\/\/)`
	URLUsername     string = `(\S+(:\S*)?@)`
	URLPath         string = `((\/|\?|#)[^\s]*)`
	URLPort         string = `(:(\d{1,5}))`
	URLIP           string = `([1-9]\d?|1\d\d|2[01]\d|22[0-3]|24\d|25[0-5])(\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])){2}(?:\.([0-9]\d?|1\d\d|2[0-4]\d|25[0-5]))`
	URLSubdomain    string = `((www\.)|([a-zA-Z0-9]+([-_\.]?[a-zA-Z0-9])*[a-zA-Z0-9]\.[a-zA-Z0-9]+))`
	URL                    = `^` + URLSchema + `?` + URLUsername + `?` + `((` + URLIP + `|(\[` + IP + `\])|(([a-zA-Z0-9]([a-zA-Z0-9-_]+)?[a-zA-Z0-9]([-\.][a-zA-Z0-9]+)*)|(` + URLSubdomain + `?))?(([a-zA-Z\x{00a1}-\x{ffff}0-9]+-?-?)*[a-zA-Z\x{00a1}-\x{ffff}0-9]+)(?:\.([a-zA-Z\x{00a1}-\x{ffff}]{1,}))?))\.?` + URLPort + `?` + URLPath + `?$`
	SSN             string = `^\d{3}[- ]?\d{2}[- ]?\d{4}$`
)

var rxURL = regexp.MustCompile(URL)

// IsURL function
func IsURL(str string) bool {
	if str == "" || utf8.RuneCountInString(str) >= maxURLRuneCount || len(str) <= minURLRuneCount || strings.HasPrefix(str, ".") {
		return false
	}
	strTemp := str
	if strings.Contains(str, ":") && !strings.Contains(str, "://") {
		// 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)
}

const charset = "abcdefghijklmnopqrstuvwxyz" +
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

var seededRand *rand.Rand = rand.New(
	rand.NewSource(time.Now().UnixNano()))

// StringWithCharset - Create RAndom and Unique String
func StringWithCharset(length int, charset string) string {
	b := make([]byte, length)
	for i := range b {
		b[i] = charset[seededRand.Intn(len(charset))]
	}
	return string(b)
}