OnConnectedAsync ist sometimes called with the wrong HubConnectionContext

[Machibuse]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have a c# SignalR Server and Client.

The connections are authenticated via a AuthenticationHandler that checks a http header and sets NameIdentifier claim on success.

I have overridden OnConnectedAsync like this:

public override Task OnConnectedAsync()
{
    Logger.LogDebug("OnConnectedAsync {UserIdentifier} {ConnectionId}", Context.UserIdentifier, Context.ConnectionId);
    return Task.CompletedTask;
}

Now i have 12 Clients connecting sequencially to the Host, everything works fine, i see 12 different Users and ConnectionIds in the log.

When i now restart the host, all 12 clients get disconnected an they reconnects after a few seconds. All nearly exact at the same time.

Now i can see 12 log entries in my log, but not all entries have different connection Ids. Some times there are 12 log entrys with the same ConnectionId and the Same UserIdentifier, sometimes 2 or 3 Different ConnectionIds.

But there are always Exact 12 Log entrys and all clients are connected.

Log looks like this

OnConnectedAsync bx-1112-a15b Auh6pXikG_Z_yv-DKd2f7w
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A
OnConnectedAsync bx-6d0d-a085 lAHrxx264qEiy3DVGyBr3A

Expected Behavior

The resulting log should look more like this

OnConnectedAsync bx-559c-bf6b -AuuForEsEmkekc7zl-MFg
OnConnectedAsync bx-8136-3d61 vGzZ3ueAEfXoywbvPRCe8w
OnConnectedAsync bx-a879-10bf q3R7KdUJNBIJX9NsCEZjUg
OnConnectedAsync bx-1112-a15b APXIiXndlvToA7EGRGp6Sg
OnConnectedAsync bx-6d0d-a085 vnigiIvux6uZTFUdJ8jaZQ
OnConnectedAsync bx-5074-7cdf UxnUyiiDnNExL9Zsi2BZGQ
OnConnectedAsync bx-ab74-7078 v_w2XHaL2hWFsdEz0biTFQ
OnConnectedAsync bx-f865-0aa5 hwKVxqG_PcHlhnBxTF7mnQ
OnConnectedAsync bx-078b-ba40 iZ4v7sCklCsSa1fYGBHTBA
OnConnectedAsync bx-4bb1-2f20 ymKoUF7OU0lwu1_otgkvkg
OnConnectedAsync bx-e8fa-cae0 GOVZoyQrHQH22qb5BiQi7g
OnConnectedAsync bx-8136-3d61 NRqC5IIPIBAL2Dz4fJH_kA

this.Context shoult point to the correct HubConnectionContext inside OnConnectedAsync

Steps To Reproduce

If you need ist, i can try to make a small sample Project that reproduces the problem. If you have questione or any ideas what i can try, feel free to ask me.

Exceptions (if any)

I have tested the behavior on different Computers and it seems that there are no problems when the Host ist running on a very slow machine

.NET Version

Microsoft.AspNetCore.App 8.0.1

Anything else?

No response

[davidfowl]

If you need ist, i can try to make a small sample Project that reproduces the problem. If you have questione or any ideas what i can try, feel free to ask me.

Yep we're going to need a minimal repro.

[Machibuse]

If you need ist, i can try to make a small sample Project that reproduces the problem. If you have questione or any ideas what i can try, feel free to ask me.

Yep we're going to need a minimal repro.

ok, i will try to create one

[Machibuse]

Hi I have written a small sample Project zu reproduce the problem

https://github.com/Machibuse/SignalRTest/tree/main

There is a test.bat file for testing.

• It compiles Host and client
• It starts 20 clients to connect to the host with usernames "user01" to "user20" connectiong to http://localhost:32638/myhub
• Then starting the Hub
• All 20 Clients get connected

The Log in the Server in OnConnectedAsync looks lite this

MyHub created
OnConnectedAsync user02 yJ4pu51S3HShegvfZPoZvw
OnConnectedAsync user02 yJ4pu51S3HShegvfZPoZvw
OnConnectedAsync user02 yJ4pu51S3HShegvfZPoZvw
OnConnectedAsync user02 yJ4pu51S3HShegvfZPoZvw
OnConnectedAsync user06 PVKgmTt0IqkWZtGV3npesw
OnConnectedAsync user07 nhYiJUEXfm1i7p2TF_dPkw
OnConnectedAsync user05 RAXwkw3wNpIIpcu8xJ9Dmw
OnConnectedAsync user10 iK4eBbE02PURlTfItvODIA
OnConnectedAsync user11 S29TN3g6PoCcSOlKP6Gxpg
OnConnectedAsync user08 TlBxt29NnzNv2DbwW1DJzQ
OnConnectedAsync user12 OIGlPesL4sNwmjkf18KItg
OnConnectedAsync user13 4mSyzMfQDh8gSgeldy8F5A
OnConnectedAsync user09 ULmuhLVtFgy16DGfLKmJhw
OnConnectedAsync user15 GA1OKXmBd1EUuDmROJEl_Q
OnConnectedAsync user14 Cgbyb5Ip2wlG7HltYL5Umw
OnConnectedAsync user19 F3B4Lub1B9jsjvLdqAmOjg
OnConnectedAsync user18 s_B9QGAFzccmTA9uvWWxpQ
OnConnectedAsync user20 Sr_et6mDwQNlTHIpcgkb_Q
OnConnectedAsync user16 rzFwPOKtlK9g95FgXcre9w
OnConnectedAsync user17 ooGFcnpOUPKD35uJusfMgg

You see in my sample OnConnectedAsync for user02 called 4 times, OnConnectedAsync for user 01 03 and 04 are missing.

you can press any key to stop and restart the hub and somthing like this happens again, exactly 20 on connected events but not 20 different connections

OnConnectedAsync user10 ili3BMKdilmaCxz5bKhcIA
OnConnectedAsync user10 ili3BMKdilmaCxz5bKhcIA
OnConnectedAsync user10 ili3BMKdilmaCxz5bKhcIA
OnConnectedAsync user01 bFlau9P62ZUOgato2g5xNQ
OnConnectedAsync user10 ili3BMKdilmaCxz5bKhcIA
OnConnectedAsync user10 ili3BMKdilmaCxz5bKhcIA
OnConnectedAsync user08 ZGYH9CPQc8mw0jzxuwqFlg
OnConnectedAsync user06 GiTMbOfrUklQtHGeROSSbA
OnConnectedAsync user15 yq3uchIYIYdUpEbOCL-1ag
OnConnectedAsync user07 J3xfJTQTMjms75y-RqSHHw
OnConnectedAsync user07 J3xfJTQTMjms75y-RqSHHw
OnConnectedAsync user11 0QhIAAQU7Bh0XMjYIF2YTg
OnConnectedAsync user04 5Sqt-n879UnBQ5HmTtlx8w
OnConnectedAsync user19 yaGnYkB2VDzk-9NNQH20hg
OnConnectedAsync user16 vQQFUuTsYgAfnep-sAtqCQ
OnConnectedAsync user18 NKOPyNByuyuSAFAo4KSXlg
OnConnectedAsync user09 85Hjxb4mLlENeGpl6ybHzQ
OnConnectedAsync user17 MpD0PJMEfDjBvD5crqXj6Q
OnConnectedAsync user14 rn0VsE4l7X4n3TMXGbO7xw
OnConnectedAsync user13 V12dbdJ1nHchMzgR1yxNew

[Machibuse]

Problem stays the same is you remove the Authentication part

20 OnConnectedAsync events, but xj0RG1C-AYAGQS9Q7wNmQQ is connected 9 times

OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync xj0RG1C-AYAGQS9Q7wNmQQ
OnConnectedAsync 6ORsez4_f6XWOWUL2z1jUg
OnConnectedAsync S0di3pluUE0KqUJeRTOTLg
OnConnectedAsync g576e19kkDYXVfIy5l1k6A
OnConnectedAsync iEzyUH4X9vIR8li5iL2qVA
OnConnectedAsync R2XQJzjLef8rVwhChMuRQg
OnConnectedAsync nI82pY9Gxa7Q6e9AqOgBSA
OnConnectedAsync VABSUGrt8N9JKuwhdNlm-w
OnConnectedAsync 46tzPWYyN2acOCCejNNB2Q
OnConnectedAsync ndCaeFqZhaJEatneZq9zGg
OnConnectedAsync CWdtv6bo_889VcQGDGNkyg
OnConnectedAsync n3AB4uo5n2Xf28x0vwZQ5w

[davidfowl]

Problem stays the same is you remove the Authentication part

Can you remove it then?

[Machibuse]

Problem stays the same is you remove the Authentication part

Can you remove it then?

i found the problem

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSignalR();
builder.Services.AddSingleton<MyHub>();
builder.WebHost.UseUrls("http://*:32638/");

var app = builder.Build();

app.MapHub<MyHub>("/myhub");

var task = app.RunAsync();

when i remove the line

builder.Services.AddSingleton();

it works as expected. i will commit a smaller version

[davidfowl]

@BrennanConroy we should just throw when people add singleton hubs. This is a foot gun. @Machibuse hubs are supposed to be transient.

[Machibuse]

ok, i have updated the repo.

i think this could be fatal also for other people. I can use AddSingleton and everything works fine for a long Time, and users did not detect that they have problems. Because they only occures when there are many connections at the same time.

i hope it is possible for you to detect this for you an raise an error, to beware other people from the same " foot gun" :-)

[BrennanConroy]

@BrennanConroy we should just throw when people add singleton hubs.

I tried in the past #40396

[BrennanConroy]

Dupe of #46707

[dotnet-policy-service]

This issue has been resolved and has not had any activity for 1 day. It will be closed for housekeeping purposes.

See our Issue Management Policies for more information.