Creating an envelope struct type inside our helpers file to update our writeJSON data type method's parameter. Updating healthcheckHandler and showMovieHandler with this new type to update our responses.

cmd/api/healthcheck.go

@@ -13,13 +13,13 @@ initialize it in main()
 */
 func (app *application) healthcheckHandler(w http.ResponseWriter, r *http.Request) {
 	// Create a map which holds the information that we want to send in the response.
-	data := map[string]string{
+	env := envelope{
 		"status":      "available",
 		"environment": app.config.env,
 		"version":     version,
 	}
 
-	err := app.writeJSON(w, http.StatusOK, data, nil)
+	err := app.writeJSON(w, http.StatusOK, env, nil)
 	if err != nil {
 		app.logger.Error(err.Error())
 		http.Error(w, "The server encountered a problem and could not process your request", http.StatusInternalServerError)

cmd/api/helpers.go

@@ -43,12 +43,14 @@ func (app *application) readIDParam(r *http.Request) (int64, error) {
 	return id, nil
 }
 
+type envelope map[string]any
+
 /*
 Define a writeJSON() helper for sending responses. This takes the destination
 http.ResponseWriter, the HTTP status code to send, the data to encode to JSON, and a
 header map containing any additional HTTP headers we want to include in the response.
 */
-func (app *application) writeJSON(w http.ResponseWriter, status int, data any, headers http.Header) error {
+func (app *application) writeJSON(w http.ResponseWriter, status int, data envelope, headers http.Header) error {
 	/*
 		Use the json.MarshalIndent() function so that whitespace is added to
 		the encoded JSON. Here we use no line prefix ("") and tab indents ("\t") for each element.

cmd/api/movies.go

@@ -36,7 +36,7 @@ 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, movie, nil)
+	err = app.writeJSON(w, http.StatusOK, envelope{"movie": movie}, nil)
 	if err != nil {
 		app.logger.Error(err.Error())
 		http.Error(w, "The server encountered a problem and could not process your request", http.StatusInternalServerError)