c# - DownloadString with WebClient - 404 Error

Question

I am trying to download string from discord webhook :("https://discordapp.com/api/webhooks/704770710509453432/GdR4absQHKDKjUiNMpw3aIpX2tx-9Z7nmPE2Sn3TUkQDM12zUczaV-m80orh7WGVzvGK")

When I normally open the site with browser string is : {"message": "Unknown Webhook", "code": 10015}

But when I do that with WebClient:

           WebClient wc = new WebClient();
           string site = "https://discordapp.com/api/webhooks/704770710509453432/GdR4absQHKDKjUiNMpw3aIpX2tx-9Z7nmPE2Sn3TUkQDM12zUczaV-m80orh7WGVzvGK";
           string x = wc.DownloadString(site);

It gives an "404 Error". Is there a way to get that {"message": "Unknown Webhook", "code": 10015} string with c#?

Answer 1

A rough guess would be that it's to do with the accept header. Check the documentation for the api, but my browser sent an additional 17 headers along with the request.

---

The simple answer would be, use HttpClient. It's recommended for new development and also gives the correct response here:

using System;
using System.Net.Http;
using System.Threading.Tasks;

namespace discordapi_headers
{
    class Program
    {
        static async Task Main(string[] args)
        {
            var client = new HttpClient();
            var response = await client.GetAsync("https://discordapp.com/api/webhooks/704770710509453432/GdR4absQHKDKjUiNMpw3aIpX2tx-9Z7nmPE2Sn3TUkQDM12zUczaV-m80orh7WGVzvGK");
            Console.WriteLine(await response.Content.ReadAsStringAsync());
        }
    }
}

However that doesn't help if you can't. Also I'm intrigued now...

---

Ha! I should have listened to my own advice. For web service related stuff, you can't beat fiddler and postman. It turns out that the api is returning a custom 404 to the browser that has json content.

Unfortunately DownloadString sees the 404 and throws a WebException.

Here's an updated version that works, using HttpClient and WebClient.

using System;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

namespace discordapi_headers
{
    class Program
    {
        static readonly string url = "https://discordapp.com/api/webhooks/704770710509453432/GdR4absQHKDKjUiNMpw3aIpX2tx-9Z7nmPE2Sn3TUkQDM12zUczaV-m80orh7WGVzvGK";

        static async Task Main(string[] args)
        {
            Console.WriteLine(await UseHttpClient(url));
            Console.WriteLine(await UseWebClient(url));
        }

        private static async Task<string> UseHttpClient(string url)
        {
            var client = new HttpClient();
            var response = await client.GetAsync(url);
            return await response.Content.ReadAsStringAsync();
        }

        private static async Task<string> UseWebClient(string url)
        {
            var client = new WebClient();
            try
            {
                var response = await client.DownloadStringTaskAsync(url);
                return response;
            }
            catch (WebException wex)
            {
                using (var s = wex.Response.GetResponseStream())
                {
                    var buffer = new byte[wex.Response.ContentLength];
                    var contentBytes = await s.ReadAsync(buffer, 0, buffer.Length);
                    var content = Encoding.UTF8.GetString(buffer);
                    return content;
                }
            }
        }
    }
}