I am not getting any output and i don't know why

Question

using System;
using System.Text;

namespace ConsoleApp7
{
    class Program
    {
        static void Main(string[] args)
        {
            YourClient client = new YourClient();
            
            client.Put();
        }

        public class YourClient
        {
            private readonly HttpClient _client;

            public YourClient()
            {
                _client = new HttpClient();
            }

            public async Task Put() // must be async
            {
                using (var request = new HttpRequestMessage(HttpMethod.Put, "https://api.minecraftservices.com/minecraft/profile/name/egg"))
                {
                    request.Headers.Add("Authorization", "Bearer token");
                    request.Content = new StringContent("body", Encoding.UTF8, "content-type");

                    using (var response = await _client.SendAsync(request))
                    {
                        var data = await response.Content.ReadAsStringAsync();
                        var code = response.StatusCode;
                        Console.WriteLine(Convert.ToString(code));

                        // do something with data
                    }
                }
            }
        }
    }
}

I'm not getting any output and I don't know why. I'm trying to print the response code of the request but nothing is output, is it to do with my method?

I have tried printing hi after Client.Put() and it was printed, so I know that my code is actually running, I just don't know why it isn't printing the status code ...

Answer 1

The excellent comment by Prolog points out one of two issues. If your Console app is built on < C# 7.1 you will need a workaround to prevent the app from exiting (before the request has time to process) so in this case add Console.ReadKey() as the very last line. This will spin the message loop until you hit a key. But this is not the main issue and I would like to offer a couple of debugging tips.

The big issue is this:

• If I run your code, your http request is failing and is throwing a System.FormatException
• Usually this type of exception is not set to Break when Thrown. (You can verify this by looking in the Exception Settings window.) Unfortunately, this is giving you a silent failure in this case, so you must take matters into your own hands to observe it.

Suggestions for debugging your code

1. Use a try-catch block around any code that has any likelihood of failing.

2. Use System.Diagnostics.Debug.Assert which will cause your program to break on a line if any condition expression evaluates to false (but only when you're running in Debug mode not Release mode).

3. Add output statements to trace execution. Using Debug.WriteLine will send messages to the Output window (but again, only in Debug mode). Alternatively, since we have a Console app here, I'm using the main app window to output trace statements.

Example using 1-3:

public async Task Put() // must be async
{
    Console.WriteLine("Begin Put()");
    try
    {
        using (var request = new HttpRequestMessage(HttpMethod.Put, "https://api.minecraftservices.com/minecraft/profile/name/egg"))
        {
            request.Headers.Add("Authorization", "Bearer token");
            request.Content = new StringContent("body", Encoding.UTF8, "content-type");

            using (var response = await _client.SendAsync(request))
            {
                var data = await response.Content.ReadAsStringAsync();
                var code = response.StatusCode;
                Console.WriteLine(Convert.ToString(code));

                // do something with data
            }
        }
    }
    catch (Exception ex)
    {
        System.Diagnostics.Debug.Assert(condition: false, message: ex.Message);
    }
    Console.WriteLine("End Put()");
}

Now, if I run the code it will break and show what the problem is.

4. Use the Exception Settings window to turn on all exceptions (if in doubt). Now the code will break on the exact line that is the problem.

5. Verify that you are Setting Authorization Header of HttpClient correctly as this may be part of the root cause of the exception.

Finally, if you continue after the Debug.Assert you will see the following text in your console which will confirm whether your Put method has had a chance to complete or not.

Hope these suggestions help you solve this problem and future ones!

---

// This workaround for C# versions below 7.1 attempts to 
// mimic an `async Main` method. 
static void Main(string[] args)
{
    RunAsync();
    Console.ReadKey();
}

private static async void RunAsync()
{
    YourClient client = new YourClient();
    // Put() should be awaited inside an async method
    await client.Put();
}