[PR] Add debug function (#3)

* [debug] add debugConnection(url)

* [flag] add debug

* [debug] add debug logic

fgit.go

@@ -4,12 +4,77 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
+	"net"
+	"net/http"
 	"os"
 	"os/exec"
 	"path"
 	"strings"
 )
 
+func debugConnection(url string) bool {
+	fmt.Print("Test connection...")
+	response, err := http.Head(url)
+	if err != nil {
+		fmt.Println("Failed")
+		fmt.Println("Response create failed\n", err)
+		return false
+	}
+	if response.StatusCode != http.StatusOK {
+		fmt.Println("Failed")
+		return false
+	} else {
+		fmt.Println("Success")
+		return true
+	}
+}
+
+func debug(url string) bool {
+	if url != "--help" {
+		fmt.Println("" +
+			"FastGit Debug Tool\n" +
+			"==================\n" +
+			"Remote Address:", url)
+		fmt.Print("IP Address: ")
+		addr, err := net.LookupIP(strings.Replace(strings.Replace(url, "https://", "", -1), "http://", "", -1))
+		if err != nil {
+			fmt.Println("Unknown")
+		} else {
+			fmt.Println(addr)
+		}
+
+		fmt.Print("Local Address: ")
+		resp, err := http.Get("https://api.ip.sb/ip")
+		defer resp.Body.Close()
+		if err != nil {
+			fmt.Println("Unknown -> ", err)
+		} else {
+			s, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				fmt.Println("Unknown -> ", err)
+			} else {
+				fmt.Printf("[%s]\n", strings.Replace(string(s), "\n", "", -1))
+			}
+		}
+
+		return debugConnection(url)
+	} else {
+		fmt.Println("" +
+			"FastGit Debug Command Line Tool\n" +
+			"===============================\n" +
+			"SYNTAX\n" +
+			"    fgit debug [URL<string>] [--help]\n" +
+			"REMARKS\n" +
+			"    URL is an optional parameter\n" +
+			"    We debug https://hub.fastgit.org by default\n" +
+			"    If you want to debug another URL, enter URL param\n" +
+			"EXAMPLE\n" +
+			"    fgit debug\n" +
+			"    fgit debug https://fastgit.org")
+		return true
+	}
+}
+
 func convertToFastGit() bool {
 	return convertHelper("https://github.com", "https://hub.fastgit.org")
 }
@@ -48,18 +113,40 @@ func checkErr(err error, msg string, exitCode int) {
 }
 
 func main() {
-	if len(os.Args) == 1 {
+	if len(os.Args) == 1 || (len(os.Args) == 2 && os.Args[1] == "--help") {
 		fmt.Println("" +
 			"FastGit Command Line Tool\n" +
 			"=========================\n" +
-			"We will convert GitHub to FastGit automatically\n" +
-			"Do everything like git\n" +
-			"Build by KevinZonda with GoLang")
+			"REMARKS\n" +
+			"    We will convert GitHub to FastGit automatically\n" +
+			"    Do everything like git\n" +
+			"    Build by KevinZonda with GoLang\n" +
+			"EXTRA-SYNTAX\n" +
+			"    fgit debug [URL<string>] [--help]\n" +
+			"    If you wan to known more about extra-syntax, try to use --help")
 		os.Exit(0)
 	}
 
 	isConvertToFastGit := false
 	isPush := false
+
+	if os.Args[1] == "debug" {
+		var isConnectOk bool
+		switch len(os.Args) {
+		case 2:
+			isConnectOk = debug("https://hub.fastgit.org")
+		case 3:
+			isConnectOk = debug(os.Args[2])
+		default:
+			fmt.Println("Invalid args for debug. If help wanted, use --help arg.")
+		}
+		if isConnectOk {
+			os.Exit(0)
+		} else {
+			os.Exit(1)
+		}
+	}
+
 	for i := range os.Args {
 		if os.Args[i] == "push" {
 			isPush = true