How to capture an error occurring on a webapi server?

Question

I have a server where runs a Webapi service, in the client I run the call to a POST URL so:

try
{
   HttpWebRequest request;

   request = (HttpWebRequest)WebRequest.Create(URL);

   request.Method = "POST";
   request.Proxy = null;
   request.ContentType = "application/json";

   byte[] dataStream = Encoding.UTF8.GetBytes(DATA);
   Stream newStream = request.GetRequestStream();
   newStream.Write(dataStream, 0, dataStream.Length);
   newStream.Close();

   request.GetResponse();
}
catch (Exception ex)
{

   //QUERO LER O ERRO AQUI
}

On the server I do the treatment like this:

try
{

...

}
catch (Exception ex)
{

   return Request.CreateErrorResponse(HttpStatusCode.InternalServerError,ex);
}

The problem is that in the customer he comes a exception saying that made mistake 500, I know that the exception not "coming" from the server, which is generated in the client, but I would like to know how I get the inner all generated in the CreateErrorResponse

Answer 1

By default, details of the exception occurring on the server are not placed in the HTTP response. This is to not show details of the server implementation to the client - it is a security measure. The less the client knows about the innards of the server, the better.

The exception details are only placed on the HTTP response if the client is local, that is, if the client and the server were on the same computer.

However, if this API is for internal consumption, you can choose to display the exception details for all customers, using HttpConfiguration.IncludeErrorDetailPolicy.

In the file WebApiConfig.cs, adds:

config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;

On the server, the exception will be converted to an instance of HttpError and serialized in the body of the answer. Then, on the client side, just convert back to HttpError.

Note: it is preferable to use the HttpClient instead of WebRequest to make HTTP requests, as it has a high-level API and avoids dealing directly with byte streams. This whole code can be written like this:

using (var client = new HttpClient())
{
    var response = await client.PostAsJsonAsync("url", data);

    if (response.IsSuccessStatusCode)
    {
        var error = await response.Content.ReadAsAsync<HttpError>();
    }
    else
    {
        var responseData = await response.Content.ReadAsAsync<Model>();
    }
}