c# - Posting to a Web API using HttpClient and Web API method [FromBody] parameter ends up being null

Question

I am attempting to POST to a Web API using the HttpClient. When I put a breakpoint in the Save method of the Web API the [FromBody] Product is null. This means that something is wrong with the way I am posting the product over to the Web API. Can someone please take a look at the below code and see where I might be going wrong. I am assuming it is something to do with headers and content types.

POST call from a client repository to the Web API which should pass the product object through as JSON:

public async Task<Product> SaveProduct(Product product)
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri("http://localhost:99999/");
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        StringContent content = new StringContent(JsonConvert.SerializeObject(product));
        // HTTP POST
        HttpResponseMessage response = await client.PostAsync("api/products/save", content);
        if (response.IsSuccessStatusCode)
        {
            string data = await response.Content.ReadAsStringAsync();
            product = JsonConvert.DeserializeObject<Product>(data);
        }
    }
    return product;
}

Web API Controller Method:

[HttpPost]
[Route("save")]
public IActionResult Save([FromBody]Product product)
{
    if (customer == null)
    {
        return HttpBadRequest();
    }
    _manager.SaveCustomer(product);
    return CreatedAtRoute("Get", new { controller = "Product", id = product.Id }, product);
}

[FromBody] Product product parameter ends up being null.

Answer 1

Have you tried inspecting the request in something like fiddler? It needs the content-type to be application/json as you have pointed out. But you are only setting the accept header.

Try:

StringContent content = new StringContent(JsonConvert.SerializeObject(product), Encoding.UTF8, "application/json");