HTTP Errors When Using POST Methods - asp.net-core

Question

I can't quite seem to figure out how to call HTTP POST functions from my Blazor WASM project hosted with ASP.NET. I am having trouble finding any examples of using POST methods past .NET 6 likely because it's so new. I've tried setting content-headers to JSON and many different ways of retrieving the request body from the actual controller function, but I just get 500, 415, and 400 errors. I've also tried not using model binding the the controller function, but to no avail. I do not believe this is the issue though, as using the [ApiController] attribute infers proper model binding as far as I know. I can only imagine the issue stems from the HTTP call.
The service that calls the method:
public async Task CreateUser(User user)
{
await _httpClient.PostAsJsonAsync("users", user);
}
The controller function:
[HttpPost]
public async Task PostUser(User user)
{
_context.Users.Add(user);
await _context.SaveChangesAsync();
}
The given from the above code is just a simple 400 error.
Also, I've added a test user into the database manually, and I'm able to retrieve it without any issues.

Answer 1

Here's some code from one of my demo projects showing API calls to get WeatherForecast records.
Here's the Web Assembly project DataBroker:
public class WeatherForecastAPIDataBroker : IWeatherForecastDataBroker
{
private readonly HttpClient? httpClient;
public WeatherForecastAPIDataBroker(HttpClient httpClient)
=> this.httpClient = httpClient!;
public async ValueTask<bool> AddForecastAsync(WeatherForecast record)
{
var response = await this.httpClient!.PostAsJsonAsync<WeatherForecast>($"/api/weatherforecast/add", record);
var result = await response.Content.ReadFromJsonAsync<bool>();
return result;
}
public async ValueTask<bool> DeleteForecastAsync(Guid Id)
{
var response = await this.httpClient!.PostAsJsonAsync<Guid>($"/api/weatherforecast/delete", Id);
var result = await response.Content.ReadFromJsonAsync<bool>();
return result;
}
public async ValueTask<List<WeatherForecast>> GetWeatherForecastsAsync()
{
var list = await this.httpClient!.GetFromJsonAsync<List<WeatherForecast>>($"/api/weatherforecast/list");
return list!;
}
}
And here's the controller it's calling:
namespace Blazr.Demo.Controllers;
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
private IWeatherForecastDataBroker weatherForecastDataBroker;
public WeatherForecastController(IWeatherForecastDataBroker weatherForecastDataBroker)
=> this.weatherForecastDataBroker = weatherForecastDataBroker;
[Route("/api/weatherforecast/list")]
[HttpGet]
public async Task<List<WeatherForecast>> GetForecastAsync()
=> await weatherForecastDataBroker.GetWeatherForecastsAsync();
[Route("/api/weatherforecast/add")]
[HttpPost]
public async Task<bool> AddRecordAsync([FromBody] WeatherForecast record)
=> await weatherForecastDataBroker.AddForecastAsync(record);
[Route("/api/weatherforecast/delete")]
[HttpPost]
public async Task<bool> DeleteRecordAsync([FromBody] Guid Id)
=> await weatherForecastDataBroker.DeleteForecastAsync(Id);
}
The Repo for the Demo Project Blazor.Demo
Controller Code
Data Broker Code