first commit

.gitignore

@@ -19,3 +19,6 @@
 
 # Go workspace file
 go.work
+
+.vscode/
+.env

go.mod

@@ -0,0 +1,18 @@
+module github.com/zhang2092/go-url-shortener
+
+go 1.21.5
+
+require (
+	github.com/gorilla/mux v1.8.1
+	github.com/itchyny/base58-go v0.2.1
+	github.com/redis/go-redis/v9 v9.3.1
+	github.com/stretchr/testify v1.8.4
+)
+
+require (
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,24 @@
+github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
+github.com/bsm/ginkgo/v2 v2.12.0/go.mod h1:SwYbGRRDovPVboqFv0tPTcG1sN61LM1Z4ARdbAV9g4c=
+github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
+github.com/bsm/gomega v1.27.10/go.mod h1:JyEr/xRbxbtgWNi8tIEVPUYZ5Dzef52k01W3YH0H+O0=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
+github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
+github.com/itchyny/base58-go v0.2.1 h1:wtnhAVdOcW3WuHEASmGHMms4juOB8yEpj/KJxlB57+k=
+github.com/itchyny/base58-go v0.2.1/go.mod h1:BNvrKeAtWNSca1GohNbyhfff9/v0IrZjzWCAGeAvZZE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/redis/go-redis/v9 v9.3.1 h1:KqdY8U+3X6z+iACvumCNxnoluToB+9Me+TvyFa21Mds=
+github.com/redis/go-redis/v9 v9.3.1/go.mod h1:hdY0cQFCN4fnSYT6TkisLufl/4W5UIXyv0b/CLO2V2M=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

handler/handlers.go

@@ -0,0 +1,74 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/zhang2092/go-url-shortener/shortener"
+	"github.com/zhang2092/go-url-shortener/store"
+)
+
+type UrlCreationRequest struct {
+	LongUrl string `json:"long_url"`
+	UserId  string `json:"user_id"`
+}
+
+type UrlCreationResponse struct {
+	Message  string `json:"message"`
+	ShortUrl string `json:"short_url"`
+}
+
+func CreateShortUrl(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	var req UrlCreationRequest
+	err := json.NewDecoder(r.Body).Decode(&req)
+	if err != nil {
+		http.Error(w, "invalid parameter", http.StatusInternalServerError)
+		return
+	}
+
+	shortUrl, err := shortener.GenerateShortLink(req.LongUrl, req.UserId)
+	if err != nil {
+		http.Error(w, "failed to generate short link", http.StatusInternalServerError)
+		return
+	}
+
+	err = store.SaveUrlMapping(shortUrl, req.LongUrl, req.UserId)
+	if err != nil {
+		http.Error(w, "failed to store url mapping", http.StatusInternalServerError)
+		return
+	}
+
+	scheme := "http://"
+	if r.TLS != nil {
+		scheme = "https://"
+	}
+
+	res := &UrlCreationResponse{
+		Message:  "short url created successfully",
+		ShortUrl: scheme + r.Host + "/" + shortUrl,
+	}
+
+	b, err := json.Marshal(res)
+	if err != nil {
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	w.Write(b)
+}
+
+func HandleShortUrlRedirect(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	shorUrl := vars["shortUrl"]
+	link, err := store.RetrieveInitialUrl(shorUrl)
+	if err != nil {
+		http.Error(w, "failed to get url", http.StatusInternalServerError)
+		return
+	}
+
+	http.Redirect(w, r, link, http.StatusFound)
+}

main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/gorilla/mux"
+	"github.com/zhang2092/go-url-shortener/handler"
+	"github.com/zhang2092/go-url-shortener/store"
+)
+
+func main() {
+	router := mux.NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("Wecome to the URL Shortener API"))
+	}).Methods(http.MethodGet)
+
+	router.HandleFunc("/create-short-url", handler.CreateShortUrl).Methods(http.MethodPost)
+	router.HandleFunc("/{shortUrl}", handler.HandleShortUrlRedirect).Methods(http.MethodGet)
+
+	store.InitializeStore()
+
+	srv := &http.Server{
+		Addr:         "0.0.0.0:9090",
+		Handler:      router,
+		WriteTimeout: 15 * time.Second,
+		ReadTimeout:  15 * time.Second,
+	}
+
+	go func() {
+		if err := srv.ListenAndServe(); err != nil {
+			log.Printf("failed to start server on :9000, err: %v", err)
+		}
+	}()
+
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt)
+	<-c
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	store.CloseStoreRedisConn()
+
+	srv.Shutdown(ctx)
+	log.Println("shutting down")
+	os.Exit(0)
+}

shortener/shortener.go

@@ -0,0 +1,35 @@
+package shortener
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"math/big"
+
+	"github.com/itchyny/base58-go"
+)
+
+func sha256Of(input string) []byte {
+	algorithm := sha256.New()
+	algorithm.Write([]byte(input))
+	return algorithm.Sum(nil)
+}
+
+func base58Encoded(bytes []byte) (string, error) {
+	encoded, err := base58.BitcoinEncoding.Encode(bytes)
+	if err != nil {
+		return "", err
+	}
+
+	return string(encoded), nil
+}
+
+func GenerateShortLink(originUrl string, userId string) (string, error) {
+	urlHashByte := sha256Of(originUrl + userId)
+	generateNumber := new(big.Int).SetBytes(urlHashByte).Uint64()
+	result, err := base58Encoded([]byte(fmt.Sprintf("%d", generateNumber)))
+	if err != nil {
+		return "", err
+	}
+
+	return result, nil
+}

shortener/shortener_test.go

@@ -0,0 +1,26 @@
+package shortener
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const userId = "7c729139-7ff4-445f-976b-2d842f55cb0e"
+
+func TestGenerateShortLink(t *testing.T) {
+	link1 := "https://www.baidu.com/"
+	short1, err := GenerateShortLink(link1, userId)
+	assert.NoError(t, err)
+	assert.Equal(t, short1, "egtq236P5f3")
+
+	link2 := "https://www.163.com/"
+	short2, err := GenerateShortLink(link2, userId)
+	assert.NoError(t, err)
+	assert.Equal(t, short2, "DiCqg9YpV89")
+
+	link3 := "https://www.qq.com/"
+	short3, err := GenerateShortLink(link3, userId)
+	assert.NoError(t, err)
+	assert.Equal(t, short3, "4QhQ62cZem1")
+}

store/store.go

@@ -0,0 +1,54 @@
+package store
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+type StorageService struct {
+	redisClient *redis.Client
+}
+
+var (
+	storeService = &StorageService{}
+	ctx          = context.Background()
+)
+
+const CacheDuration = 6 * time.Hour
+
+func InitializeStore() {
+	redisClient := redis.NewClient(&redis.Options{
+		Addr:     "localhost:6378",
+		Password: "secret",
+		DB:       0,
+	})
+
+	pong, err := redisClient.Ping(ctx).Result()
+	if err != nil {
+		log.Fatalf("failed to init redis: %v", err)
+	}
+
+	fmt.Printf("Redis started successfully, ping message = %s\n", pong)
+	storeService.redisClient = redisClient
+}
+
+func CloseStoreRedisConn() {
+	storeService.redisClient.Close()
+}
+
+func SaveUrlMapping(shortUrl string, originUrl string, userId string) error {
+	return storeService.redisClient.Set(ctx, shortUrl, originUrl, CacheDuration).Err()
+}
+
+func RetrieveInitialUrl(shortUrl string) (string, error) {
+	result, err := storeService.redisClient.Get(ctx, shortUrl).Result()
+	if err != nil {
+		return "", err
+	}
+
+	return result, nil
+}