Golang : Validate hostname
Problem :
You need to validate if a given string is a valid hostname or not. Hostnames such as :
www.socketloop.com
socketloop.com
google.com
digitalocean.com
Solution :
Use regexp.Compile
function to validate the string.
For example :
package main
import (
"fmt"
"regexp"
"strings"
)
func validHost(host string) bool {
host = strings.Trim(host, " ")
re, _ := regexp.Compile(`^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$`)
if re.MatchString(host) {
return true
}
return false
}
func main() {
host1 := "socketloop.com"
vHost := validHost(host1)
fmt.Printf("%s is a valid hostname : %v \n", host1, vHost)
host2 := "socketloop_com"
vHost2 := validHost(host2)
fmt.Printf("%s is a valid hostname : %v \n", host2, vHost2)
host3 := "socketloop/com"
vHost3 := validHost(host3)
fmt.Printf("%s is a valid hostname : %v \n", host3, vHost3)
host4 := "www.socketloop.com"
vHost4 := validHost(host4)
fmt.Printf("%s is a valid hostname : %v \n", host4, vHost4)
}
Output :
socketloop.com is a valid hostname : true
socketloop_com is a valid hostname : false
socketloop/com is a valid hostname : false
www.socketloop.com is a valid hostname : true
See also : Golang : Validate IP address
By Adam Ng
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