Version 1.2: Add error handling

API.go

@@ -1,13 +1,23 @@
 package main
 
 import (
+	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"net"
 	"net/http"
+	"os"
+	"sort"
+	"strings"
 )
 
 func getLocalIP() string {
-	resp, _ := http.Get("https://api.ipify.org")
+	resp, err := http.Get("https://api.ipify.org")
+	if err != nil {
+		fmt.Println("FATAL: Cannot get local IP.")
+		os.Exit(2)
+		return ""
+	}
 	body, _ := ioutil.ReadAll(resp.Body)
 	return string(body[:])
 }
@@ -24,3 +34,37 @@ func resolveDNSHostname(hostname string) string {
 	address, _ := net.LookupHost(hostname)
 	return address[0]
 }
+
+func getIPInfo(ipaddress string) IPAddressInfo {
+	apiEndpoint := "http://ip-api.com/json/" + ipaddress
+	resp, err := http.Get(apiEndpoint)
+	if err != nil {
+		fmt.Println("FATAL: Cannot contact IP address information API.")
+		os.Exit(3)
+	}
+	body, _ := ioutil.ReadAll(resp.Body)
+	infoString := string(body)
+	var info IPAddressInfo
+	err = json.Unmarshal([]byte(infoString), &info)
+	if err != nil {
+		fmt.Println("FATAL: Cannot serialize recieved IP address data.")
+		os.Exit(4)
+	}
+	return info
+}
+
+func getBGPPrefixes(as string) {
+	apiEndpoint := "https://api.hackertarget.com/aslookup/?q=" + as
+	resp, err := http.Get(apiEndpoint)
+	if err != nil {
+		fmt.Println("FATAL: Cannot contact BGP Prefixes API.")
+		os.Exit(5)
+	}
+	body, _ := ioutil.ReadAll(resp.Body)
+	prefixesString := string(body)
+	var prefixes = strings.Split(prefixesString, "\n")[1:]
+	sort.Strings(prefixes)
+	for index := range prefixes {
+		fmt.Println(prefixes[index])
+	}
+}

Header.go

@@ -11,4 +11,5 @@ func printHeader() {
 	fmt.Println("|      By Luke Tainton       |")
 	fmt.Println("|        @luketainton        |")
 	fmt.Println("------------------------------")
+	fmt.Println("")
 }

IPInfo.go

@@ -1,11 +1,8 @@
 package main
 
 import (
-	"encoding/json"
 	"fmt"
-	"io/ioutil"
-	"net/http"
-	"sort"
+	"os"
 	"strings"
 )
 
@@ -27,33 +24,10 @@ type IPAddressInfo struct {
 	IPAddress    string  `json:"query"`
 }
 
-func getIPInfo(ipaddress string) IPAddressInfo {
-	apiEndpoint := "http://ip-api.com/json/" + ipaddress
-	resp, _ := http.Get(apiEndpoint)
-	body, _ := ioutil.ReadAll(resp.Body)
-	infoString := string(body)
-	var info IPAddressInfo
-	err := json.Unmarshal([]byte(infoString), &info)
-	if err != nil {
-		fmt.Println(err)
-	}
-	return info
-}
-
-func getBGPPrefixes(as string) {
-	apiEndpoint := "https://api.hackertarget.com/aslookup/?q=" + as
-	resp, _ := http.Get(apiEndpoint)
-	body, _ := ioutil.ReadAll(resp.Body)
-	prefixesString := string(body)
-	var prefixes = strings.Split(prefixesString, "\n")[1:]
-	sort.Strings(prefixes)
-	for i := 0; i < len(prefixes); i++ {
-		fmt.Println(prefixes[i])
-	}
-}
-
 func printIPInfo(input string, wantPrefixes bool) {
 	var IPInfo IPAddressInfo = getIPInfo(input)
+	fmt.Printf("%+v\n", IPInfo)
+	os.Exit(200)
 	var location string = IPInfo.Country + "/" + IPInfo.RegionName + "/" + IPInfo.City
 	var bgpAS string = strings.Fields(IPInfo.AS)[0]
 	fmt.Println("IP Address:	", IPInfo.IPAddress)

Main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"os"
 )
 
 func main() {
@@ -10,20 +11,29 @@ func main() {
 
 	var input string
 	var wantPrefixes bool
-	localIPAddress := getLocalIP()
-	flag.StringVar(&input, "i", localIPAddress, "Specify IP address or domain name.")
+
+	flag.StringVar(&input, "i", "", "Specify IP address or domain name.")
 	flag.BoolVar(&wantPrefixes, "p", false, "Enable printing of advertised BGP prefixes.")
 	flag.Parse()
-	var isIPCorrect bool = checkIPSyntax(input)
-	if isIPCorrect == true {
-		printIPInfo(input, wantPrefixes)
+
+	if input == "" {
+		fmt.Println("FATAL: No IP address or domain name was specified.")
+		os.Exit(1)
 	} else {
-		ipaddress := resolveDNSHostname(input)
-		if checkIPSyntax(ipaddress) == true {
-			fmt.Println("Domain Name:	", input)
-			printIPInfo(ipaddress, wantPrefixes)
+		if input == "me" {
+			input = getLocalIP()
+		}
+		var isIPCorrect bool = checkIPSyntax(input)
+		if isIPCorrect == true {
+			printIPInfo(input, wantPrefixes)
 		} else {
-			fmt.Println("Invalid query.")
+			ipaddress := resolveDNSHostname(input)
+			if checkIPSyntax(ipaddress) == true {
+				fmt.Println("Domain Name:	", input)
+				printIPInfo(ipaddress, wantPrefixes)
+			} else {
+				fmt.Println("Invalid query.")
+			}
 		}
 	}