feat: permissions, middleware authentication, migrations

projects/greenlight/cmd/api/errors.go

@@ -88,3 +88,18 @@ func (app *application) invalidAuthenticationTokenResponse(w http.ResponseWriter
 	message := "invalid or missing authentication token"
 	app.errorResponse(w, r, http.StatusUnauthorized, message)
 }
+
+func (app *application) authenticationRequiredResponse(w http.ResponseWriter, r *http.Request) {
+	message := "you must be authenticated to access this resource"
+	app.errorResponse(w, r, http.StatusUnauthorized, message)
+}
+
+func (app *application) inactiveAccountResponse(w http.ResponseWriter, r *http.Request) {
+	message := "your user account must be activated to access this resource"
+	app.errorResponse(w, r, http.StatusForbidden, message)
+}
+
+func (app *application) notPermittedResponse(w http.ResponseWriter, r *http.Request) {
+	message := "your user account doesn't have the necessary permissions to access this resource"
+	app.errorResponse(w, r, http.StatusForbidden, message)
+}

projects/greenlight/cmd/api/middleware.go

@@ -181,3 +181,66 @@ func (app *application) authenticate(next http.Handler) http.Handler {
 		next.ServeHTTP(w, r)
 	})
 }
+
+// anonymous.
+func (app *application) requireAuthenticatedUser(next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user := app.contextGetUser(r)
+
+		if user.IsAnonymous() {
+			app.authenticationRequiredResponse(w, r)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+// Checks that a user is both authenticated and activated.
+func (app *application) requireActivatedUser(next http.HandlerFunc) http.HandlerFunc {
+	// Rather than returning this http.HandlerFunc we assign it to the variable fn.
+	fn := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user := app.contextGetUser(r)
+
+		// Check that a user is activated.
+		if !user.Activated {
+			app.inactiveAccountResponse(w, r)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+
+	// Wrap fn with the requireAuthenticatedUser() middleware before returning it.
+	return app.requireAuthenticatedUser(fn)
+}
+
+// Note that the first parameter for the middleware function is the permission code that
+// we require the user to have.
+func (app *application) requirePermission(code string, next http.HandlerFunc) http.HandlerFunc {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		// Retrieve the user from the request context.
+		user := app.contextGetUser(r)
+
+		// Get the slice of permissions for the user.
+		permissions, err := app.models.Permissions.GetAllForUser(user.ID)
+		if err != nil {
+			app.serverErrorResponse(w, r, err)
+			return
+		}
+
+		// Check if the slice includes the required permission. If it doesn't, then
+		// return a 403 Forbidden response.
+		if !permissions.Include(code) {
+			app.notPermittedResponse(w, r)
+			return
+		}
+
+		// Otherwise they have the required permission so we call the next handler in
+		// the chain.
+		next.ServeHTTP(w, r)
+	}
+
+	// Wrap this with the requireActivatedUser() middleware before returning it.
+	return app.requireActivatedUser(fn)
+}

projects/greenlight/cmd/api/routes.go

@@ -9,24 +9,24 @@ import (
 func (app *application) routes() http.Handler {
 	router := httprouter.New()
 
-	// Convert the notFoundResponse() helper to a http.Handler using the
-	// http.HandlerFunc() adapter, and then set it as the custom error handler for 404
-	// Not Found responses.
 	router.NotFound = http.HandlerFunc(app.notFoundResponse)
-
-	// Likewise, convert the methodNotAllowedResponse() helper to a http.Handler and set
-	// it as the custom error handler for 405 Method Not Allowed responses.
 	router.MethodNotAllowed = http.HandlerFunc(app.methodNotAllowedResponse)
-	router.HandlerFunc(http.MethodGet, "/v1/movies", app.listMoviesHandler)
+
 	router.HandlerFunc(http.MethodGet, "/v1/healthcheck", app.healthcheckHandler)
-	router.HandlerFunc(http.MethodPost, "/v1/movies", app.createMovieHandler)
-	router.HandlerFunc(http.MethodGet, "/v1/movies/:id", app.showMovieHandler)
-	router.HandlerFunc(http.MethodPatch, "/v1/movies/:id", app.updateMovieHandler)
-	router.HandlerFunc(http.MethodDelete, "/v1/movies/:id", app.deleteMovieHandler)
+
+	// Use the requirePermission() middleware on each of the /v1/movies** endpoints,
+	// passing in the required permission code as the first parameter.
+	router.HandlerFunc(http.MethodGet, "/v1/movies", app.requirePermission("movies:read", app.listMoviesHandler))
+	router.HandlerFunc(http.MethodPost, "/v1/movies", app.requirePermission("movies:write", app.createMovieHandler))
+	router.HandlerFunc(http.MethodGet, "/v1/movies/:id", app.requirePermission("movies:read", app.showMovieHandler))
+	router.HandlerFunc(http.MethodPatch, "/v1/movies/:id", app.requirePermission("movies:write", app.updateMovieHandler))
+	router.HandlerFunc(http.MethodDelete, "/v1/movies/:id", app.requirePermission("movies:write", app.deleteMovieHandler))
+
 	router.HandlerFunc(http.MethodPost, "/v1/users", app.registerUserHandler)
 	router.HandlerFunc(http.MethodPut, "/v1/users/activated", app.activateUserHandler)
-	router.HandlerFunc(http.MethodPost, "/v1/tokens/authentication", app.createAuthenticationTokenHandler)
-	// Wrap the router with the rateLimit() middleware.
-	// Use the authenticate() middleware on all requests.
+
+	router.HandlerFunc(http.MethodPost, "/v1/tokens/authentication",
+		app.createAuthenticationTokenHandler)
+
 	return app.recoverPanic(app.rateLimit(app.authenticate(router)))
 }