Add Get and Post handlers with simple storage

cmd/shortener/main.go

@@ -1,3 +1,96 @@
 package main
 
-func main() {}
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+type Storage struct {
+	storage map[string]string
+}
+
+func (s *Storage) Add(short string, url string) {
+	s.storage[short] = url
+}
+
+func (s *Storage) Get(short string) (string, bool) {
+	url, ok := s.storage[short]
+	return url, ok
+}
+
+func CreateStorage() *Storage {
+	return &Storage{storage: make(map[string]string)}
+}
+
+var urlStorage = CreateStorage()
+
+func shortenURL(url string) string {
+	// Решил использовать хэширование и первые символы результата, как короткую форму URL
+	hash := md5.Sum([]byte(url))
+	hashString := hex.EncodeToString(hash[:])
+	shortURL := hashString[:8]
+	return shortURL
+}
+
+func main() {
+	mux := http.NewServeMux()
+	mux.HandleFunc(`/`, defineHandler)
+
+	err := http.ListenAndServe(`:8080`, mux)
+
+	if err != nil {
+		fmt.Println("Error:", err)
+	}
+}
+
+func defineHandler(res http.ResponseWriter, req *http.Request) {
+	if req.Method == http.MethodPost && req.URL.Path == "/" {
+		postHandler(res, req)
+	} else if req.Method == http.MethodGet && req.URL.Path != "/" {
+		getHandler(res, req)
+	} else {
+		invalidRequestHandler(res, req)
+	}
+}
+
+func postHandler(res http.ResponseWriter, req *http.Request) {
+	body, err := io.ReadAll(req.Body)
+	if err != nil {
+		http.Error(res, "Error reading request body", http.StatusInternalServerError)
+		return
+	}
+	defer req.Body.Close()
+
+	url := string(body)
+	short := shortenURL(url)
+
+	urlStorage.Add(short, url)
+
+	res.Header().Set("Content-Type", "text/plain")
+	res.WriteHeader(http.StatusCreated)
+	res.Write([]byte("http://localhost:8080/" + short))
+}
+
+func getHandler(res http.ResponseWriter, req *http.Request) {
+	id := req.URL.Path[len("/"):]
+	if id == "" || strings.Contains(id, "/") {
+		http.Error(res, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	url, ok := urlStorage.Get(id)
+	if !ok {
+		http.NotFound(res, req)
+		return
+	}
+	res.Header().Set("Location", url)
+	res.WriteHeader(http.StatusTemporaryRedirect)
+}
+
+func invalidRequestHandler(res http.ResponseWriter, req *http.Request) {
+	http.Error(res, "Bad Request", http.StatusBadRequest)
+}

go.mod

@@ -0,0 +1,5 @@
+module github.com/shilin-anton/urlreducer
+
+go 1.21.3
+
+require github.com/gorilla/mux v1.8.1 // indirect