Angular - Using HttpClient for handling POST requests

The example provided in the official Angular HttpClient documentation demonstrates how to make a POST request to a backend server.

/** POST: add a new hero to the database */
addHero (hero: Hero): Observable<Hero> {
  return this.http.post<Hero>(this.heroesUrl, hero, httpOptions)
    .pipe(
      catchError(this.handleError('addHero', hero))
    );
}

I find it puzzling that the Observable is returning Hero data instead of just a success code for a POST request. While I grasp the concept of type assertion for GET requests, I'm struggling to comprehend its use in this scenario.

angulartypescripthttppost

Answer №1

Yes, it is true that a successful POST request will return with a success code. The reason for this specific mention in the documentation might be unclear, but I can explain based on my understanding.

The response from a POST request can vary depending on how your API is implemented. For instance, if your database has default values set for certain fields like the createDate of a Hero, and you want to access this field in your Angular application, you would need to send the Hero data from the API.

In the example provided in the docs, they are using a mock-api. If you were to log the response, you would typically see a status of 204. By default, when this status is returned, no body is sent with the response. However, you can configure your mock service to include the body by modifying it as follows:

HttpClientInMemoryWebApiModule.forRoot(InMemHeroService, {put204: false, post204: false})

With this configuration, you will receive a 200 response along with the Hero body.

Answer №2

Exploring the given scenario, addHero appears to be a component of a superhero "utility" that is inserted into the SuperheroesComponent. The SuperheroesComponent then listens to the utility method and adds the new superhero returned from the database to the superheroes list.

Let's observe the SuperheroesComponent subscribing to the addSuperhero observable. The SuperheroesComponent triggers the POST action by subscribing to the observable provided by the utility method:

this.superheroesUtility.addSuperhero(newSuperhero)
  .subscribe(superhero => this.superheroesList.push(superhero));

Answer №3

One of the main advantages of using a Web API that accepts POST requests is that it typically sends back the newly created object as part of the response.

This backend functionality becomes particularly valuable when you require specific properties such as ID or creation time that are only accessible after the object has been successfully added through the POST request on the server side.

For additional information, refer to .

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