THREAD IT

main.go

@@ -1,8 +1,11 @@
 package main
 
 import (
+	"bufio"
 	"fmt"
 	"log"
+	"os"
+	"sync"
 	"time"
 
 	"github.com/likexian/whois"
@@ -10,36 +13,45 @@ import (
 )
 
 func main() {
+	var wg sync.WaitGroup
+
+	i := 1
+	for r := 'a'; r <= 'z'; r++ {
+		wg.Add(1)
+		go runForLetter(&wg, i, fmt.Sprintf("%c", r))
+		i++
+	}
+
+	wg.Wait()
+	log.Printf("Done!")
+}
+
+func runForLetter(wg *sync.WaitGroup, id int, letter string) {
+	defer wg.Done()
 	freeDomains := []string{}
 
 	domainsToCheck := generateInput()
 
 	for _, domain := range domainsToCheck {
-		resp, err := checkDomain(domain)
+		log.Printf("Checking " + letter + domain + ".nz")
+		resp, err := checkDomain(letter + domain + ".nz")
 		if err != nil {
 			log.Fatal(err)
 		}
 
 		if resp {
-			log.Printf("%s is free!", domain)
-			freeDomains = append(freeDomains, domain)
-		} else {
-			log.Printf("%s is not free!", domain)
+			freeDomains = append(freeDomains, letter+domain+".nz")
 		}
 	}
 
-	log.Println()
-	log.Println("Free Domains:")
-
-	for _, v := range freeDomains {
-		log.Print(v)
-	}
+	writeLinesToFile(letter, freeDomains)
 
+	fmt.Printf("Worker %v: Finished\n", id)
 }
 
 // checkDomain - True if available, error/false if not
 func checkDomain(domain string) (bool, error) {
-	time.Sleep(time.Second * 5)
+	time.Sleep(time.Millisecond * 100)
 	resultRaw, err := whois.Whois(domain, "whois.srs.net.nz")
 	if err != nil {
 		return false, err
@@ -60,11 +72,31 @@ func checkDomain(domain string) (bool, error) {
 func generateInput() []string {
 	output := []string{}
 
-	for o := 'a'; o <= 'z'; o++ {
-		for r := 'a'; r <= 'z'; r++ {
-			output = append(output, fmt.Sprintf("%c", o)+fmt.Sprintf("%c", r))
+	for r := 'a'; r <= 'z'; r++ {
+		for x := 'a'; x <= 'z'; x++ {
+			output = append(output, fmt.Sprintf("%c", r)+fmt.Sprintf("%c", x))
 		}
 	}
 
 	return output
 }
+
+func writeLinesToFile(letter string, str []string) {
+	if len(str) == 0 {
+		return
+	}
+
+	file, err := os.OpenFile(letter+".char.txt", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+
+	if err != nil {
+		log.Fatalf("failed creating file: %s", err)
+	}
+	datawriter := bufio.NewWriter(file)
+
+	for _, data := range str {
+		_, _ = datawriter.WriteString(data + "\n")
+	}
+
+	datawriter.Flush()
+	file.Close()
+}