使用HttpClient通过GET连接到WebApi时出现404错误

Question

I'm getting a 404 error when trying to use an HttpClient to connect to a WebApi service using GET. However, POST works without any problem. In the code below, I have a CreditCard class that I use throughout.

Here's my routing configuration:

config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

Here's my code that calls the async operation:

Task task1 = RegisterCard(card, false);
Task task2 = FetchCard(cardid, false);

Here's my code that contains the the async operations:

private async Task RegisterCard(CreditCard card, bool runAsync)
{
    try
    {
        using (HttpClient client = new HttpClient())
        {
            client.BaseAddress = new Uri("http://localhost:63801/");
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            HttpResponseMessage response = runAsync
                                            ? await client.PostAsJsonAsync("api/card", card)
                                            : client.PostAsJsonAsync("api/card", card).Result;

            response.EnsureSuccessStatusCode();
        }
    }
    catch (HttpRequestException ex)
    {
        throw new HttpRequestException(ex.Message, ex.InnerException);
    }
}

private async Task FetchCard(int cardid, bool runAsync)
{
    CreditCard card = new CreditCard();

    try
    {
        using (HttpClient client = new HttpClient())
        {
            client.BaseAddress = new Uri("http://localhost:63801/");
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            HttpResponseMessage response = runAsync
                                            ? await client.GetAsync("api/card/" + cardid)
                                            : client.GetAsync("api/card/" + cardid).Result;

            response.EnsureSuccessStatusCode();
            }
        }
    }
    catch (HttpRequestException ex)
    {
        throw new HttpRequestException(ex.Message, ex.InnerException);
    }
}

Here's my code for the apiController:

[HttpPost]
public HttpResponseMessage Register(CreditCard card)
{
    HttpResponseMessage result;

    try
    {
        RegisterResponse response = _cardRepository.Register(card);

        result = Request.CreateResponse(HttpStatusCode.Created, response);
    }
    catch (Exception ex)
    {
        // TODO: add logging
        result = Request.CreateErrorResponse(HttpStatusCode.BadRequest, "failed to register card");
    }
    finally
    {
        // TODO: add audit logging of what attempted and who attempted it
    }

    return result;
}

[HttpGet]
public CreditCard Fetch(int cardid)
{
    CreditCard card = new CreditCard();

    try
    {
        card = _cardRepository.Fetch(cardid);
    }
    catch (Exception ex)
    {
        // TODO: add logging
    }
    finally
    {
        // TODO: add audit logging of what attempted and who attempted it
    }

    return card;
}

And my code for the CardRepository:

public RegisterResponse Register(Models.CreditCard card)
{
    using (CreditCardContext ccContext = new CreditCardContext())
    {
        card.MaskedNumber = "XXXXXXXXXXXX" + card.Number.Substring(card.Number.Length - 4, 4);
        card.Number = Crypto.EncryptData_Aes(card.Number, KeyType.CardNumberKey);
        card.CardGuid = Guid.NewGuid().ToString();
        ccContext.CreditCards.Add(card);
        ccContext.SaveChanges();
    }
    card.ResetSensitive();

    RegisterResponse response = new RegisterResponse
    {
        IsSuccess = true,
        Message = "successfully registered card",
        CreditCard = card
    };

    return response;
}

public CreditCard Fetch(int cardid) // , bool masked
{
    CreditCard card;

    using (CreditCardContext ccContext = new CreditCardContext())
    {
        card = ccContext.CreditCards.SingleOrDefault(x => x.Card_ID == cardid);
    }

    return card;
}

QUESTION: Why am I getting a 404 error when using an HttpClient object to connect to my WebApi service using HttpGet, but when I use HttpPost, it works correctly?

Answer 1

The problem is the parameter naming in your Fetch method.

If you change it to id as per the route specified it should work:

[HttpGet]
public CreditCard Fetch(int id) // , bool masked
{
   ...
}

Or, alternatively, you could call the api with the named param (eg api/card/?cardid=2 )

Answer 2

In Web API 2 you can use Attribute Routing

[Route("api/card/{cardid:int}")]
[HttpGet]
public CreditCard Fetch(int cardid)
{
    ...
}