Implement map method to check longurl exist or not

Signed-off-by: viveksahu26 <vivekkumarsahu650@gmail.com>

README.md

@@ -5,10 +5,10 @@
 1) go run main.go
 
 2)  
-    Enter your URL after *http://localhost:8080/short-url?longURL=*
+    Enter your URL after *http://localhost:8080/enterLongURL?longURL=*
     And let's say your URL is *http://google.com/1346461234567890123456789/get/vivekkumarsahu*
     Finally you complete URL will look like:
-```http://localhost:8080/short-url?longURL=http://google.com/1346461234567890123456789/get/vivekkumarsahu```
+```http://localhost:8080/enterLongURL?longURL=http://google.com/1346461234567890123456789/get/vivekkumarsahu```
 
 3) You will get output
 ```
@@ -49,11 +49,16 @@
 
     Example:
     Now, copy and paste to your browser:
-
-    http://localhost:49154/short-url?longURL=http://google.com/1346461234567890123456789/get/viveksahu26
+
+## Step:3
+    http://localhost:8090/enterLongURL?longURL=http://google.com/1346461234567890123456789/get/viveksahu26
+
+    OR
+
+    http://localhost:49154/enterLongURL?longURL=http://google.com/1346461234567890123456789/get/viveksahu26
 
 
 
-    DockerHub: https://hub.docker.com/repository/docker/viveksahu26/my-url-shortner
+    Docker Image: https://hub.docker.com/repository/docker/viveksahu26/my-url-shortner:v1.0.0
 
     *NOTE*: Do not forget to change port number(49154) and also replace this url(http://google.com/1346461234567890123456789/get/viveksahu26) with your URL.

main.go

@@ -14,7 +14,7 @@ func handleShortURL(writer http.ResponseWriter, req *http.Request) {
 	fmt.Println("originalURL: ", originalURL)
 
 	// generate random shortURL
-	shortURL := src.GenerateShortURL()
+	shortURL := src.GenerateShortURL(originalURL)
 	fmt.Println("shortURL: ", shortURL)
 
 	// save short and long URL to file
@@ -46,8 +46,8 @@ func main() {
 		ReadTimeout:  30 * time.Second,
 	}
 
-	// handleShortUrl function mapped to /short-url
-	serveMux.HandleFunc("/short-url", handleShortURL)
+	// handleShortUrl function mapped to /enterLongURL
+	serveMux.HandleFunc("/enterLongURL", handleShortURL)
 
 	// Server Listing on "localhost:8080"
 	srv.ListenAndServe()

src/saveInfile.go

@@ -2,6 +2,7 @@ package src
 
 import (
 	"errors"
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
@@ -11,38 +12,60 @@ import (
 // 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) {
-		os.Create(fileName)
-		os.WriteFile(fileName, []byte(prop+"\n"), 0o644)
-	} else {
+	isFileExist, _ := IsFileExist(fileName)
 
-		input, err := ioutil.ReadFile(fileName)
-		if err != nil {
-			log.Fatalln(err)
-		}
+	combinedURL := shortURL + "=" + longURL
 
-		lines := strings.Split(string(input), "\n")
+	if !isFileExist {
+		fmt.Printf("New file %s is created.", fileName)
+		os.Create(fileName)
+		os.WriteFile(fileName, []byte(combinedURL+"\n"), 0o644)
 
-		var flag bool
-		for i, line := range lines {
-			if strings.Contains(line, shortURL) {
-				lines[i] = prop
-				flag = true
-			}
-		}
-		if flag {
-			output := strings.Join(lines, "\n")
-			err = ioutil.WriteFile(fileName, []byte(output), 0o644)
-			if err != nil {
-				log.Fatalln(err)
-			}
-		} else {
+	} else {
+		fmt.Printf("File %s already exist.", fileName)
+		_, msg, fileContainLongURL := IsLongURLPresentInFile(fileName, longURL)
+		fmt.Println("\n", msg)
+
+		if !fileContainLongURL {
 			file, err := os.OpenFile(fileName, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
 			if err != nil {
 				panic(err)
 			}
-			_, _ = file.WriteString(prop + "\n")
+			_, _ = file.WriteString(combinedURL + "\n")
+		}
+	}
+}
+
+func IsFileExist(fileName string) (bool, error) {
+	if _, err := os.Stat(fileName); errors.Is(err, os.ErrNotExist) {
+		return false, err
+	}
+	return true, nil
+}
+
+func IsLongURLPresentInFile(fileName, longURL string) (map[string]string, string, bool) {
+	fileBytes, err := ioutil.ReadFile(fileName)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	fileContent := strings.Split(string(fileBytes), "\n")
+
+	var fileContainLongURL bool
+	var message string
+	ShortAndLongURLValue := make(map[string]string)
+	for _, line := range fileContent {
+		totalURL := strings.Split(line, "=")
+		if len(totalURL) == 2 {
+			ShortAndLongURLValue[totalURL[1]] = totalURL[0]
+		}
+
+		if strings.Contains(line, longURL) {
+			message = fmt.Sprintln("Yes, URL is already present in the file")
+			fileContainLongURL = true
+			return ShortAndLongURLValue, message, fileContainLongURL
 		}
+		message = fmt.Sprintln("URL is not present in the file.")
 	}
+	fmt.Println("\n", message)
+	return ShortAndLongURLValue, message, fileContainLongURL
 }

src/shortURLGenerator.go

@@ -10,7 +10,23 @@ type Result struct {
 }
 
 // Generate Random URL of 10 characters
-func GenerateShortURL() string {
+// First check LongURL is present in the file or not
+// If present, then get that existing shortURL corresponditing to that LongURL
+// Otherwise generate new ShortURL
+func GenerateShortURL(longURL string) string {
+	fileName := "url.properties"
+	isFilePresent, _ := IsFileExist(fileName)
+
+	if isFilePresent {
+		shortAndLongURLKeyValuePair, _, fileContainLongURL := IsLongURLPresentInFile(fileName, longURL)
+
+		if fileContainLongURL {
+			// then retrieve ShortURL from there.
+			if shorturl, ok := shortAndLongURLKeyValuePair[longURL]; ok {
+				return shorturl
+			}
+		}
+	}
 	allCharacters := []rune("%$#@!*^+0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 	randomChar := make([]rune, 10)
 	for i := range randomChar {