GetDomainname()

README.md

@@ -1,3 +1,6 @@
 Get() the full hostname for the OS.
 
 * only cares about the hostname in DNS
+* I wrote this before or not being aware of os.Hostname()
+
+probably this package should go away

common.go

@@ -11,7 +11,7 @@ var ErrorEmptyDomainName error = errors.New("domain name is empty")
 var ErrorDomainNameMisconfigured error = errors.New("your OS domain name is not configured correctly")
 
 // returns 'hostname', 'domainname'
-func Split(s string) (string, string) {
+func SplitOld(s string) (string, string) {
 	parts := strings.Fields(s)
 	if len(parts) == 0 {
 		return "", ""
@@ -24,7 +24,7 @@ func Split(s string) (string, string) {
 
 // checks to make sure there is a domainname
 func ValidDomainname(s string) error {
-	_, domainname := Split(s)
+	_, domainname := SplitOld(s)
 	if domainname == "" {
 		return ErrorEmptyDomainName
 	}

domainname.go

@@ -0,0 +1,62 @@
+package hostname
+
+import (
+	"fmt"
+	"strings"
+)
+
+// for www.corp.wit.com retuns:
+// "www", "corp.wit.com", nil
+func GetDomainname() (string, string, error) {
+	hname, err := osGetHostname()
+	if err != nil {
+		return hname, "", err
+	}
+	hname = strings.TrimSpace(hname)
+	hname = strings.Trim(hname, ".")
+	parts := strings.Split(hname, ".")
+	if len(parts) == 0 {
+		return "", "", fmt.Errorf("domainname not set")
+	}
+
+	if len(parts) == 1 {
+		return parts[0], "", fmt.Errorf("domainname not set")
+	}
+
+	dname := strings.Join(parts[1:], ".")
+
+	return hname, dname, nil
+}
+
+// splits hostname into first and last part
+// for www.corp.wit.com retuns:
+// "www", "corp.wit.com", nil
+func Split(hname string) (string, string, error) {
+	hname = strings.TrimSpace(hname)
+	hname = strings.Trim(hname, ".")
+	parts := strings.Split(hname, ".")
+	if len(parts) == 0 {
+		return "", "", fmt.Errorf("domainname not set")
+	}
+
+	if len(parts) == 1 {
+		return parts[0], "", fmt.Errorf("domainname not set")
+	}
+
+	dname := strings.Join(parts[1:], ".")
+
+	return hname, dname, nil
+}
+
+func Join(hname string, dname string) string {
+	hname = strings.TrimSpace(hname)
+	hname = strings.Trim(hname, ".")
+	dname = strings.TrimSpace(dname)
+	dname = strings.Trim(dname, ".")
+
+	fullname := strings.Join([]string{hname, dname}, ".")
+	fullname = strings.TrimSpace(fullname)
+	fullname = strings.Trim(fullname, ".")
+
+	return fullname
+}

get.go

@@ -1,9 +1,17 @@
 package hostname
 
+import "fmt"
+
 // returns the hostname
 // hostname is always set to the best effort
 // error is set if hostname isn't real
 func Get() (string, error) {
 	hostname, err := osGetHostname()
+	if hostname == "" {
+		if err == nil {
+			err = fmt.Errorf("your machines' hostname is not set")
+		}
+		hostname = "unconfigured.hostname"
+	}
 	return hostname, err
 }

get_darwin.go

@@ -12,12 +12,12 @@ import (
 // scutil --set HostName my-mac.example.com
 
 func osGetHostname() (string, error) {
-	return scutil([]string{"-get", "HostName"})
+	return scutil([]string{"--get", "HostName"})
 }
 
 // getDomainName executes the 'domainname' command and returns its output.
 func scutil(args []string) (string, error) {
-	cmd := exec.Command("scutil", args)
+	cmd := exec.Command("scutil", args...)
 	var out bytes.Buffer
 	cmd.Stdout = &out
 	if err := cmd.Run(); err != nil {

whois.go

@@ -0,0 +1,47 @@
+package hostname
+
+import (
+	"io"
+	"net"
+)
+
+// GetWhois performs a raw whois query for a given domain.
+// Note: This does not recursively find the right server; it uses a known one.
+func GetWhois(domain, server string) (string, error) {
+	// Connect to the whois server on port 43
+	conn, err := net.Dial("tcp", net.JoinHostPort(server, "43"))
+	if err != nil {
+		return "", err
+	}
+	defer conn.Close()
+
+	// Send the domain query
+	_, err = conn.Write([]byte(domain + "\r\n"))
+	if err != nil {
+		return "", err
+	}
+
+	// Read the entire response
+	result, err := io.ReadAll(conn)
+	if err != nil {
+		return "", err
+	}
+
+	return string(result), nil
+}
+
+/*
+func main() {
+// We have to know the server for .com domains
+const whoisServer = "whois.verisign-grs.com"
+  domain :="google.com"
+
+  whoisData, err := GetWhois(domain, whoisServer)
+if err != nil {
+          log.Fatal"Error getting whois info: %v", err)
+  }
+
+  fmt.Println(whoisData)
+}
+
+*/