From 6c68afcc5be4f8fd2b007bba1f8623d479285035 Mon Sep 17 00:00:00 2001
From: viveksahu26 <vivekkumarsahu650@gmail.com>
Date: Wed, 14 Sep 2022 21:01:13 +0530
Subject: [PATCH 1/2] updating main with simpler readbility

Signed-off-by: viveksahu26 <vivekkumarsahu650@gmail.com>
---
 main.go                              | 40 +++++++++++++++-------------
 src/buildURLresponse.go              |  4 +--
 src/{savetofile.go => saveInfile.go} |  3 ++-
 src/shortURLGenerator.go             | 11 ++++----
 4 files changed, 32 insertions(+), 26 deletions(-)
 rename src/{savetofile.go => saveInfile.go} (90%)

diff --git a/main.go b/main.go
index c62aa60..396aa41 100644
--- a/main.go
+++ b/main.go
@@ -1,14 +1,14 @@
 package main
 
 import (
-	"encoding/json"
 	"fmt"
 	"net/http"
+	"time"
 
 	"github.com/viveksahu26/url_shortner/src"
 )
 
-func handleShortUrl(writer http.ResponseWriter, req *http.Request) {
+func handleShortURL(writer http.ResponseWriter, req *http.Request) {
 	// get original URL from GET method by quering
 	originalURL := req.URL.Query().Get("longURL")
 	fmt.Println("originalURL: ", originalURL)
@@ -18,33 +18,37 @@ func handleShortUrl(writer http.ResponseWriter, req *http.Request) {
 	fmt.Println("shortURL: ", shortURL)
 
 	// save short and long URL to file
-	src.SaveToFile(shortURL, originalURL)
+	src.SaveInFile(shortURL, originalURL)
 
-	host := req.Host
+	host := "www.simplifyurl.com"
 
 	// build Response
-	resp := src.BuildURLResponse(host, shortURL, originalURL)
+	resp := src.BuildURLWithResponse(host, shortURL, originalURL)
 	fmt.Println("response: ", resp)
 
-	// Converting response  JSON form
-	jsonBytes, err := json.Marshal(resp)
+	err := src.RespondWithJSON(writer, 200, resp)
 	if err != nil {
-		writer.Write([]byte("Failed to generate response"))
+		writer.Write([]byte("Failed to respond with JSON"))
 	}
-
-	writer.Header().Set("Content-Type", "application/json")
-	writer.WriteHeader(http.StatusOK)
-	writer.Write(jsonBytes)
 }
 
+const addr = "localhost:8080"
+
 func main() {
-	fmt.Println("URL Shorten Service")
+	fmt.Println("URL Shorten Service Starts ...")
+
+	// multiplexer: It provides seperate server interface for each request.
+	serveMux := http.NewServeMux()
+	srv := http.Server{
+		Handler:      serveMux,
+		Addr:         addr,
+		WriteTimeout: 30 * time.Second,
+		ReadTimeout:  30 * time.Second,
+	}
 
 	// handleShortUrl function mapped to /short-url
-	http.HandleFunc("/short-url", handleShortUrl)
+	serveMux.HandleFunc("/short-url", handleShortURL)
 
-	err := http.ListenAndServe(":8080", nil)
-	if err != nil {
-		panic(err)
-	}
+	// Server Listing on "localhost:8080"
+	srv.ListenAndServe()
 }
diff --git a/src/buildURLresponse.go b/src/buildURLresponse.go
index 52a5601..c9043bb 100644
--- a/src/buildURLresponse.go
+++ b/src/buildURLresponse.go
@@ -5,8 +5,8 @@ type URLResponse struct {
 	ShortURL    string `json:"shortURL"`
 }
 
-// It returns short URL as response
-func BuildURLResponse(host string, shortURL string, originalURL string) *URLResponse {
+// builds shortURL as response
+func BuildURLWithResponse(host string, shortURL string, originalURL string) *URLResponse {
 	resp := &URLResponse{
 		OriginalURL: originalURL,
 		ShortURL:    "http://" + host + "/" + shortURL,
diff --git a/src/savetofile.go b/src/saveInfile.go
similarity index 90%
rename from src/savetofile.go
rename to src/saveInfile.go
index c09c13b..557df27 100644
--- a/src/savetofile.go
+++ b/src/saveInfile.go
@@ -8,7 +8,8 @@ import (
 	"strings"
 )
 
-func SaveToFile(shortURL string, longURL string) {
+// Saving LongURL corresponding to ShortURL
+func SaveInFile(shortURL string, longURL string) {
 	fileName := "url.properties"
 	prop := shortURL + "=" + longURL
 	if _, err := os.Stat(fileName); errors.Is(err, os.ErrNotExist) {
diff --git a/src/shortURLGenerator.go b/src/shortURLGenerator.go
index 9874f4d..f6c83fb 100644
--- a/src/shortURLGenerator.go
+++ b/src/shortURLGenerator.go
@@ -9,11 +9,12 @@ type Result struct {
 	ShortURL    string `json:"shortURL"`
 }
 
+// Generate Random URL of 10 characters
 func GenerateShortURL() string {
-	letterRunes := []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789%$#@!*^+")
-	b := make([]rune, 8)
-	for i := range b {
-		b[i] = letterRunes[rand.Intn(len(letterRunes))]
+	allCharacters := []rune("%$#@!*^+0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	randomChar := make([]rune, 10)
+	for i := range randomChar {
+		randomChar[i] = allCharacters[rand.Intn(len(allCharacters))]
 	}
-	return string(b)
+	return string(randomChar)
 }

From 45cea2d704803188b5835c570b2a63586e78b14d Mon Sep 17 00:00:00 2001
From: viveksahu26 <vivekkumarsahu650@gmail.com>
Date: Wed, 14 Sep 2022 21:01:33 +0530
Subject: [PATCH 2/2] respond with JSON format

Signed-off-by: viveksahu26 <vivekkumarsahu650@gmail.com>
---
 src/respondWithJSON.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 src/respondWithJSON.go

diff --git a/src/respondWithJSON.go b/src/respondWithJSON.go
new file mode 100644
index 0000000..448abdc
--- /dev/null
+++ b/src/respondWithJSON.go
@@ -0,0 +1,18 @@
+package src
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// Responding with JSON format
+func RespondWithJSON(w http.ResponseWriter, status int, resp interface{}) error {
+	response, err := json.Marshal(resp)
+	if err != nil {
+		return err
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	w.Write(response)
+	return nil
+}