add authentication; refactoring and bugs fixing

internal/greenlight/auth.go

@@ -19,10 +19,10 @@ func NewAuthService(secret string) *AuthService {
 	}
 }
 
-func (a *AuthService) Create(ctx context.Context, id int64) (token string, err error) {
+func (a *AuthService) CreateToken(ctx context.Context, userID int64) (token string, err error) {
 	now := time.Now()
 	claims := &jwt.RegisteredClaims{
-		Subject:   strconv.FormatInt(id, 10),
+		Subject:   strconv.FormatInt(userID, 10),
 		IssuedAt:  jwt.NewNumericDate(now),
 		NotBefore: jwt.NewNumericDate(now),
 		ExpiresAt: jwt.NewNumericDate(now.Add(24 * time.Hour)),
@@ -32,3 +32,21 @@ func (a *AuthService) Create(ctx context.Context, id int64) (token string, err e
 
 	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString([]byte(a.secret))
 }
+
+func (a *AuthService) ParseToken(tokenString string) (userID int64, err error) {
+	token, err := jwt.Parse(
+		tokenString,
+		func(t *jwt.Token) (interface{}, error) {
+			return []byte(a.secret), nil
+		},
+		jwt.WithValidMethods([]string{jwt.SigningMethodHS256.Alg()}),
+		jwt.WithExpirationRequired(),
+		jwt.WithIssuer("github.com./denpeshkov/greenlight"),
+		jwt.WithAudience("github.com./denpeshkov/greenlight"),
+	)
+
+	if err != nil {
+		return 0, NewUnauthorizedError("Invalid or missing authentication token.")
+	}
+	return strconv.ParseInt(token.Claims.(*jwt.RegisteredClaims).Subject, 10, 64)
+}

internal/greenlight/context.go

@@ -0,0 +1,18 @@
+package greenlight
+
+import "context"
+
+type ctxKey string
+
+const (
+	userIDCtxKey ctxKey = "userID"
+)
+
+func NewContextWithUserID(ctx context.Context, userID int64) context.Context {
+	return context.WithValue(ctx, userIDCtxKey, userID)
+}
+
+func UserIDFromContext(ctx context.Context) int64 {
+	userID, _ := ctx.Value(userIDCtxKey).(int64)
+	return userID
+}

internal/http/auth.go

@@ -49,7 +49,7 @@ func (s *Server) handleCreateToken(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	token, err := s.authService.Create(r.Context(), u.ID)
+	token, err := s.authService.CreateToken(r.Context(), u.ID)
 	if err != nil {
 		s.Error(w, r, fmt.Errorf("%s: %w", op, err))
 		return

internal/http/middleware.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"strings"
 	"sync"
 	"time"
 
@@ -126,3 +127,33 @@ func (s *Server) rateLimit(h http.Handler) http.Handler {
 		h.ServeHTTP(w, r)
 	})
 }
+
+func (s *Server) authenticate(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		op := "http.Server.authenticate"
+
+		// This indicates to any caches that the response may vary based on the value of the Authorization header in the request.
+		w.Header().Add("Vary", "Authorization")
+
+		authzHeader := r.Header.Get("Authorization")
+
+		if authzHeader == "" {
+			s.Error(w, r, fmt.Errorf("%s: %w", op, greenlight.NewUnauthorizedError("You must be authenticated to access this resource.")))
+			return
+		}
+
+		headerParts := strings.Split(authzHeader, " ")
+		if len(headerParts) != 2 || headerParts[0] != "Bearer" {
+			s.Error(w, r, fmt.Errorf("%s: %w", op, greenlight.NewUnauthorizedError("Invalid or missing authentication token.")))
+			return
+		}
+
+		userId, err := s.authService.ParseToken(headerParts[1])
+		if err != nil {
+			s.Error(w, r, fmt.Errorf("%s: %w", op, err))
+			return
+		}
+		r = r.WithContext(greenlight.NewContextWithUserID(r.Context(), userId))
+		h.ServeHTTP(w, r)
+	})
+}

internal/http/movie.go

@@ -12,11 +12,11 @@ import (
 )
 
 func (s *Server) registerMovieHandlers() {
-	s.router.HandleFunc("GET /v1/movies/{id}", s.handleMovieGet)
-	s.router.HandleFunc("GET /v1/movies", s.handleMoviesGet)
-	s.router.HandleFunc("POST /v1/movies", s.handleMovieCreate)
-	s.router.HandleFunc("PATCH /v1/movies/{id}", s.handleMovieUpdate)
-	s.router.HandleFunc("DELETE /v1/movies/{id}", s.handleMovieDelete)
+	s.router.Handle("GET /v1/movies/{id}", s.authenticate(http.HandlerFunc(s.handleMovieGet)))
+	s.router.Handle("GET /v1/movies", s.authenticate(http.HandlerFunc(s.handleMoviesGet)))
+	s.router.Handle("POST /v1/movies", s.authenticate(http.HandlerFunc(s.handleMovieCreate)))
+	s.router.Handle("PATCH /v1/movies/{id}", s.authenticate(http.HandlerFunc(s.handleMovieUpdate)))
+	s.router.Handle("DELETE /v1/movies/{id}", s.authenticate(http.HandlerFunc(s.handleMovieDelete)))
 }
 
 // handleMovieGet handles requests to get a specified movie.

internal/http/server.go

@@ -53,9 +53,7 @@ func NewServer(addr string, movieService greenlight.MovieService, userService gr
 func (s *Server) Open() error {
 	op := "http.Server.Start"
 
-	handler := s.recoverPanic(s.rateLimit(s.notFound(s.methodNotAllowed(s.router))))
-
-	s.server.Handler = handler
+	s.server.Handler = s.recoverPanic(s.rateLimit(s.notFound(s.methodNotAllowed(s.router))))
 	s.server.ErrorLog = slog.NewLogLogger(s.logger.Handler(), slog.LevelError)
 
 	s.server.IdleTimeout = s.opts.idleTimeout