Using the new error's helper methods inside our current API endpoint and with our httprouter Handlers NotFound and MethodNotAllowed (will override the default responses with our helper's methods)

cmd/api/healthcheck.go

@@ -21,7 +21,7 @@ func (app *application) healthcheckHandler(w http.ResponseWriter, r *http.Reques
 
 	err := app.writeJSON(w, http.StatusOK, env, nil)
 	if err != nil {
-		app.logger.Error(err.Error())
+		// Use the new serverErrorResponse() helper
-		http.Error(w, "The server encountered a problem and could not process your request", http.StatusInternalServerError)
+		app.serverErrorResponse(w, r, err)
 	}
 }

cmd/api/movies.go

@@ -17,7 +17,8 @@ func (app *application) showMovieHandler(w http.ResponseWriter, r *http.Request)
 	id, err := app.readIDParam(r)
 
 	if err != nil || id < 1 {
-		http.NotFound(w, r)
+		// Use the new notFoundResponse() helper
+		app.notFoundResponse(w, r)
 		return
 	}
 
@@ -38,7 +39,7 @@ func (app *application) showMovieHandler(w http.ResponseWriter, r *http.Request)
 	// Encode the struct to JSON and send it as the HTTP response.
 	err = app.writeJSON(w, http.StatusOK, envelope{"movie": movie}, nil)
 	if err != nil {
-		app.logger.Error(err.Error())
+		// Use the new serverErrorResponse() helper
-		http.Error(w, "The server encountered a problem and could not process your request", http.StatusInternalServerError)
+		app.serverErrorResponse(w, r, err)
 	}
 }

cmd/api/routes.go

@@ -9,6 +9,12 @@ func (app *application) routes() http.Handler {
 	// Initialize a new httprouter router instance
 	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)
+
 	/*
 		Register the relevant methods, URL patterns and handler functions for our
 		endpoints using the HandlerFunc() method. Note that http.MethodGet and