.NET HTTP3 interop scenarios

[ladeak]

I have been experimenting with this library. I have a tool that is written in .NET 8, AOT compiled, and I try to use the C# API from a VS Code Extension (electron) app.
When the tool uses HTTP2 to make HTTP requests with HttpClient in the .NET assembly, the request is sent, and a response is received.

However, when using HTTP3 in the .NET assembly (which uses msquic on Windows), I got an empty response. I would like to better understand what could be the reason behind it: likely that it cannot access the msquic lib.
So far, I tested that the native AOT package when simply used as an executable it can make the HTTP3 requests, and responses are received.

Could you point me to the right direction to continue my investigation on this?

[jasongin]

it cannot access the msquic lib

I am aware there is currently a problem when an assembly depends on a native library that it expects to load from the same directory. So far I haven't found a good general solution. If that is the issue here, you should be able to work around the problem by explicitly loading the msquic native library with dotnet.load(). See the WPF example, which explicitly loads a couple native libraries that the WPF assemblies depend on.

[ladeak]

msquic his is not loaded from the same directory, myquic is installed with a windows update, and I see dotnet loads it like this:
And this is how .NET does it: https://source.dot.net/#System.Net.Quic/System/Net/Quic/Internal/MsQuicApi.cs,87

I am using the .NET Publish AOT solution, so I am not sure if I can use the suggested dotnet.load()

https://github.com/microsoft/msquic/blob/main/docs/Platforms.md - I just found this:

MsQuic is shipped in-box in the Windows kernel in the form of the msquic.sys driver, to support built-in HTTP and SMB features. User mode applications use msquic.dll (built from here) and package it with their app.

What confuses me is that when I "simply" run the .NET AOT app from a console it can load msquic, but not from a VS Code plugin.

I wonder if this is related: dotnet/runtime#73290

Interestingly, when I try to load the library myself by hand in .NET like this:

bool loaded = NativeLibrary.TryLoad("C:\\Windows\\System32\\drivers\\msquic.sys", out msQuicHandle);

it returns success.

[ladeak]

I will close this issue, as I think this is now an issue to be opened in .NET 8. See my comment in dotnet/runtime#73290