muonsoft / validation

package is

import (

	"net"

	"net/url"

	"regexp"

	"strings"

	"github.com/muonsoft/validation/validate"

)

// Email is used for simplified validation of an email address. It allows all values

// with an "@" symbol in, and a "." in the second host part of the email address.

func Email(value string) bool {

	return looseEmailRegex.MatchString(value)

}

// HTML5Email is used for validation of an email address based on pattern for HTML5

// (see https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address).

func HTML5Email(value string) bool {

	return html5EmailRegex.MatchString(value)

}

// URL is used to validate that value is a valid URL string. You can use a list of restrictions

// to additionally check for a restricted set of URLs. By default, if no restrictions are passed,

// the function checks for the http:// and https:// schemas.

//

// Use the callable option to configure the list of expected schemas. If an empty string

// is passed as a schema, then URL value may be treated as relative (without schema, e.g. "//example.com").

//

// Use the [github.com/muonsoft/validation/validate.RestrictURLHosts] or

// [github.com/muonsoft/validation/validate.RestrictURLHostByPattern] option to configure

// the list of allowed hosts.

func URL(value string, restrictions ...func(u *url.URL) error) bool {

	return validate.URL(value, restrictions...) == nil

}

// IP checks that a value is a valid IP address (IPv4 or IPv6). You can use a list

// of restrictions to additionally check for a restricted range of IPs.

func IP(value string, restrictions ...func(ip net.IP) error) bool {

	return validate.IP(value, restrictions...) == nil

}

// IPv4 checks that a value is a valid IPv4 address. You can use a list

// of restrictions to additionally check for a restricted range of IPs.

func IPv4(value string, restrictions ...func(ip net.IP) error) bool {

	return validate.IPv4(value, restrictions...) == nil

}

// IPv6 checks that a value is a valid IPv6 address. You can use a list

// of restrictions to additionally check for a restricted range of IPs.

func IPv6(value string, restrictions ...func(ip net.IP) error) bool {

	return validate.IPv6(value, restrictions...) == nil

}

// Hostname checks that a value is a valid hostname. It checks that each label

// within a valid hostname may be no more than 63 octets long. Also, it checks that

// the total length of the hostname must not exceed 255 characters.

//

// See [StrictHostname] for additional checks.

func Hostname(value string) bool {

	return hostnameRegex.MatchString(value) && len(strings.ReplaceAll(value, ".", "")) <= 255

}

// StrictHostname checks that a value is a valid hostname. Beside checks from Hostname function

// it checks that hostname is fully qualified and include its top-level domain name (TLD).

// For instance, example.com is valid but example is not.

//

// Additionally it checks for reserved top-level domains according to RFC 2606 and

// that's why hostnames containing them are not considered valid:

// .example, .invalid, .localhost, and .test.

func StrictHostname(value string) bool {

	if !Hostname(value) {

		return false

	}

	domains := strings.Split(value, ".")

	if len(domains) < 2 {

		return false

	}

	tld := domains[len(domains)-1]

	for _, reservedTLD := range reservedTopLevelDomains {

		if tld == reservedTLD {

			return false

		}

	}

	return true

}

var reservedTopLevelDomains = []string{

	"example",

	"invalid",

	"localhost",

	"test",

}

const (

	looseEmailPattern = `^.+\@\S+\.\S+$`

	html5EmailPattern = "^[a-zA-Z0-9.!#$%&\\'*+\\\\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)+$"

	// source https://stackoverflow.com/questions/106179/regular-expression-to-match-dns-hostname-or-ip-address

	hostnamePattern = `^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])(\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9]))*$`

)

var (

	looseEmailRegex = regexp.MustCompile(looseEmailPattern)

	html5EmailRegex = regexp.MustCompile(html5EmailPattern)

	hostnameRegex   = regexp.MustCompile(hostnamePattern)

)