Visual studio 2019 : Debugging session ended unexpectedly

Question

Visual studio 2019 : Debugging session ended unexpectedly

SSinhg 316

Hi,
Code block - is post method for creating
I'm using VS-2019 Community

debbging session ended unexpectedly... I have googled so much and tried various things but nothing has worked...
This never hits exception block...
On fiddler - request has no body but it should have... even then it should it hit the exception block!

Any help will be highly appreciated.

  var json = JsonCustomResponse.JForCreate(issuesToCreate[i]);                        
                        var content = new StringContent(json, Encoding.UTF8, "application/json");


                        using (var client = new HttpClient())
                        {
                            ConfigureHttpClient(client, restUrl);
// this is where it breaks
                            var response = await client.PostAsync(restUrl, content);
}

P a u l 10,761 Reputation points

2021-09-17T17:36:31.317+00:00

Your comment line says that it breaks on the line before the client.PostAsync, but you said that you can see a request in Fiddler. Just checking, does it it terminate when executing client.PostAsync? If not would you mind posting your ConfigureHttpClient method?

SSinhg 316

TThanks @P a u l
it teminates while executing client.PostAsync

Just tried something and it worked...
var response = await client.PostAsync(restUrl, content).Result; //This means its not async

Requested Code

    private static void ConfigureHttpClient(HttpClient client, string restUrl)  
    {  
        client.BaseAddress = new Uri(restUrl);  
        client.DefaultRequestHeaders.Authorization =  
            new AuthenticationHeaderValue("Basic", GetEncodedCredentials(userName, apiToken));  
    }  

    private static string GetEncodedCredentials(string userid, string password)  
    {  
        string mergedCredentials = string.Format("{0}:{1}", userid, password);  
        byte[] byteCredentials = UTF8Encoding.UTF8.GetBytes(mergedCredentials);  
        return Convert.ToBase64String(byteCredentials);  
    }

P a u l 10,761 Reputation points

2021-09-17T18:31:09.293+00:00

Ah, this sounds like somewhere in the callstack of your method something isn't awaiting your method, and because the execution ends before your HTTP request comes back the execution never returns to the next line after your await call.

Calling .Result does indeed block the current thread, which ideally should be avoided. There's a bit more info here:
https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task-1.result?redirectedfrom=MSDN&view=net-5.0#remarks

P a u l 10,761

An extra snippet to highlight what's happening:

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

namespace Test {
    class Program {
        static async Task Main(string[] args) {
            Test();

            // Remove this line and the program will exit before the HTTP returns
            await Task.Delay(1000);
        }

        private static async Task Test() {
            var endpoint = "https://jsonplaceholder.typicode.com/posts";

            var content = new StringContent("", Encoding.UTF8, "application/json");

            using (var client = new HttpClient()) {
                var response = await client.PostAsync(endpoint, content);

                Console.WriteLine();
            }
        }
    }
}

In this situation I can see that the Test method is highlighted as a warning in VS as the call is not awaited, but there are less obvious scenarios when this can occur.

SSinhg 316 Reputation points

2021-09-17T20:48:37.537+00:00

Thanks @Anonymous , so how do I resolve it?

should I force it to delay? and wait
P a u l 10,761 Reputation points

2021-09-17T21:04:07.3+00:00

The delay was just to demonstrate really. It depends on where your code above is run from, so I'd need to see that to get a better idea.

Just fyi in case you're wondering why we might avoid using .Wait() or .Result, it's because if the thread that's currently executing that code is the UI thread of the application then blocking that thread to wait for some async execution to complete can cause deadlocks. Here's a brief article on what situations these deadlocks might occur and also what can be done to mitigate them:
https://blog.stephencleary.com/2012/07/dont-block-on-async-code.html

Your answer

P a u l 10,761 Reputation points

2021-09-17T17:36:31.317+00:00

Your comment line says that it breaks on the line before the client.PostAsync, but you said that you can see a request in Fiddler. Just checking, does it it terminate when executing client.PostAsync? If not would you mind posting your ConfigureHttpClient method?
SSinhg 316 Reputation points

2021-09-17T17:54:10.84+00:00

TThanks @P a u l
it teminates while executing client.PostAsync

Just tried something and it worked...
var response = await client.PostAsync(restUrl, content).Result; //This means its not async

Requested Code

private static void ConfigureHttpClient(HttpClient client, string restUrl) { client.BaseAddress = new Uri(restUrl); client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", GetEncodedCredentials(userName, apiToken)); } private static string GetEncodedCredentials(string userid, string password) { string mergedCredentials = string.Format("{0}:{1}", userid, password); byte[] byteCredentials = UTF8Encoding.UTF8.GetBytes(mergedCredentials); return Convert.ToBase64String(byteCredentials); }
P a u l 10,761 Reputation points

2021-09-17T18:31:09.293+00:00

Ah, this sounds like somewhere in the callstack of your method something isn't awaiting your method, and because the execution ends before your HTTP request comes back the execution never returns to the next line after your await call.

Calling .Result does indeed block the current thread, which ideally should be avoided. There's a bit more info here:
https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task-1.result?redirectedfrom=MSDN&view=net-5.0#remarks
P a u l 10,761 Reputation points

2021-09-17T18:39:30.993+00:00

An extra snippet to highlight what's happening:

using System; using System.Net.Http; using System.Text; using System.Threading.Tasks; namespace Test { class Program { static async Task Main(string[] args) { Test(); // Remove this line and the program will exit before the HTTP returns await Task.Delay(1000); } private static async Task Test() { var endpoint = "https://jsonplaceholder.typicode.com/posts"; var content = new StringContent("", Encoding.UTF8, "application/json"); using (var client = new HttpClient()) { var response = await client.PostAsync(endpoint, content); Console.WriteLine(); } } } }

In this situation I can see that the Test method is highlighted as a warning in VS as the call is not awaited, but there are less obvious scenarios when this can occur.
SSinhg 316 Reputation points

2021-09-17T20:48:37.537+00:00

Thanks @Anonymous , so how do I resolve it?

should I force it to delay? and wait
P a u l 10,761 Reputation points

2021-09-17T21:04:07.3+00:00

The delay was just to demonstrate really. It depends on where your code above is run from, so I'd need to see that to get a better idea.

Just fyi in case you're wondering why we might avoid using .Wait() or .Result, it's because if the thread that's currently executing that code is the UI thread of the application then blocking that thread to wait for some async execution to complete can cause deadlocks. Here's a brief article on what situations these deadlocks might occur and also what can be done to mitigate them:
https://blog.stephencleary.com/2012/07/dont-block-on-async-code.html

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Visual studio 2019 : Debugging session ended unexpectedly

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