YetAnotherHttpHandler brings the power of HTTP/2 to Unity and .NET Standard.

This library enables the use of HTTP/2, which Unity does not support. It allows you to use grpc-dotnet instead of the deprecated C-core gRPC library. It can also be used for asset downloading via HTTP/2, providing more functionality to your projects.

The library is implemented as a HttpHandler for HttpClient, so you can use the same API by just replacing the handler. (drop-in replacement)

Highlights

• Unity support (including Apple Silicon support)
• Compatible with gRPC (grpc-dotnet)
• Leveraging System.Net.Http.HttpClient API

Under the hood

The handler is built on top of hyper and Rustls. It is a binding library that brings the power of those libraries to Unity and .NET.

Supported platforms and runtimes

• Unity 2021.3 (LTS) or later

• ✔ (Tier 1): Verify that it works, and active development support.
• ☁ (Tier 2): The build is available, but not confirmed to work.
• 📆 (Planned): Currently, the build is not available yet.

Features

• HTTP/1.0, HTTP/1.1
• HTTP/2
  • Multiple streams on a single connection
  • Compatible with grpc-dotnet (Grpc.Net.Client)
  • HTTP/2 over cleartext
  • TLS 1.2/1.3 with ALPN
    • TLS support is powered by Rustls + webpki
    • Client certificate
  • Unix Domain Socket (macOS, Linux)

Not supported yet

• HTTP proxy support
• Verification of certificates by security features built into the OS
• More platform supports
  • Linux on Arm

Not supported (not planned)

• NTLM and Kerberos authentication
• Platforms
  • Unity 2021.2 or earlier
  • .NET 5+
  • 32bit architectures (x86)
  • tvOS, watchOS, Tizen
    • WebGL

Installation

Unity

This library depends on the following additional libraries:

• System.IO.Pipelines (netstandard2.1)
• System.Runtime.CompilerServices.Unsafe (netstandard2.1)

Method 1: Using NuGetForUnity + GitHub

1. Install NuGetForUnity to your Unity project
2. Install the following NuGet packages via NuGetForUnity:
   • System.IO.Pipelines
   • System.Runtime.CompilerServices.Unsafe
3. Specify the following URL in Add package from git URL... of Package Manager on Unity

https://github.com/Cysharp/YetAnotherHttpHandler.git?path=src/YetAnotherHttpHandler#{Version}

Method 2: Using UnityNuGet scope registry

1. Add the UnityNuget scope registry:

https://github.com/xoofx/UnityNuGet#add-scope-registry-manifestjson

2. Specify the following URL in Add package from git URL... of Package Manager on Unity. This is the package that resolves NuGet dependencies.

https://github.com/Cysharp/YetAnotherHttpHandler.git?path=src/YetAnotherHttpHandler.Dependencies#{Version}

3. Specify the following URL in Add package from git URL... of Package Manager on Unity. This is the main packagee.

https://github.com/Cysharp/YetAnotherHttpHandler.git?path=src/YetAnotherHttpHandler#{Version}

Method 3: Install from GitHub / Git repository

1. Please download and install Cysharp.Net.Http.YetAnotherHttpHandler.Dependencies.unitypackage from the dependency redistribution on the release page.

2. Specify the following URL in Add package from git URL... of Package Manager on Unity.

https://github.com/Cysharp/YetAnotherHttpHandler.git?path=src/YetAnotherHttpHandler#{Version}

Usage

Create an instance of YetAnotherHttpHandler and pass it to HttpClient.

using Cysharp.Net.Http;

using var handler = new YetAnotherHttpHandler();
var httpClient = new HttpClient(handler);

var result = await httpClient.GetStringAsync("https://www.example.com");

With these steps, your HttpClient is now compatible with HTTP/2.✨

YetAnotherHttpHandler and HttpClient can be held following best practices and shared across multiple threads or requests.

However, since it does not have features such as connection control by the number of streams, it is necessary to separate handler instances when explicitly creating different connections.

Using gRPC (grpc-dotnet) library

To use grpc-dotnet (Grpc.Net.Client), add the following additional libraries:

• Grpc.Core.Api
• Grpc.Net.Client
• Grpc.Net.Common
• Microsoft.Extensions.Logging.Abstractions
• System.Diagnostics.DiagnosticSource

Method 1: Using NuGetForUnity

1. Install Grpc.Net.Client from NuGet via NuGetForUnity

Method 2: Using UnityNuget scope registry

To use grpc-dotnet (Grpc.Net.Client), add the following additional library to manifest.json:

{
  "dependencies": {
    "org.nuget.grpc.net.client": "{version}"
  }
}

Method 3: Install pre-built package or install the libraries manually.

Please download and install Grpc.Net.Client.Dependencies.unitypackage from the dependency redistribution on the release page, or obtain the library from NuGet.

Using GrpcChannel with YetAnotherHttpHandler

Create an instance of YetAnotherHttpHandler and pass it to GrpcChannelOptions.HttpHandler property.

using Cysharp.Net.Http;

using var handler = new YetAnotherHttpHandler();
using var channel = GrpcChannel.ForAddress("https://api.example.com", new GrpcChannelOptions() { HttpHandler = handler });
var greeter = new GreeterClient(channel);

var result = await greeter.SayHelloAsync(new HelloRequest { Name = "Alice" });

// -- OR --

using var channel = GrpcChannel.ForAddress("https://api.example.com", new GrpcChannelOptions() { HttpHandler = new YetAnotherHttpHandler(), DisposeHttpClient = true });
var greeter = new GreeterClient(channel);

var result = await greeter.SayHelloAsync(new HelloRequest { Name = "Alice" });

Configurations

When creating a YetAnotherHttpHandler instance, you can configure the following HTTP client settings.

Once the handler sends a request, these settings become immutable and cannot be changed.

Most of them expose hyper client settings, so please check those as well.

Advanced

Using HTTP/2 over cleartext (h2c)

gRPC requires communication over HTTP/2, but when it's a non-HTTPS connection, it defaults to attempting a connection with HTTP/1, causing connection issues. In this case, setting the YetAnotherHttpHandle.Http2Only property to true allows for connections via HTTP/2 over cleartext (h2c).

using var handler = new YetAnotherHttpHandler() { Http2Only = true };

Using custom root certificates

Currently, YetAnotherHttpHandler uses Mozilla's root certificates derived from webpki as the root CA.

If you want to use a self-signed certificate or a certificate issued by your organization, you need to set a custom root CA. In this case, you can specify the root certificates in pem format to RootCertificates property.

var rootCerts = @"
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
";
using var handler = new YetAnotherHttpHandler() { RootCertificates = rootCerts };

Ignore certificate validation errors

We strongly not recommend this, but in some cases, you may want to skip certificate validation when connecting via HTTPS. In this scenario, you can ignore certificate errors by setting the SkipCertificateVerification property to true.

Handling server certificate verification

You can customize the server certificate verification process by setting the OnVerifyServerCertificate property.

The callback should return true or false based on the verification result. If the property is set, the root CA verification is not performed.

using var httpHandler = new YetAnotherHttpHandler()
{
    OnVerifyServerCertificate = (serverName, certificate, now) =>
    {
        var cert = new X509Certificate2(certificate);
        return serverName == "api.example.com" &&
               cert.Subject == "CN=api.example.com";
    }
};

Using Unix Domain Sockets as HTTP transport layer

Unix Domain Sockets can be used as the HTTP transport layer for local usecases (e.g. IPC based on gRPC), instead of network-based TCP.

Set the UnixDomainSocketPath property to enable UDS-based communication to a server listening at the given path:

using var handler = new YetAnotherHttpHandler() { Http2Only = true, UnixDomainSocketPath = "/tmp/example.sock" };
using var channel = GrpcChannel.ForAddress("http://localhost", new GrpcChannelOptions() { HttpHandler = handler });

Note:

• HTTPS is not supported over UDS. All HTTPS related configuration properties are ignored if UDS is enabled.
• The grpc-dotnet library doesn't handle non-HTTP schemes (like "unix://"), so keep passing an HTTP URI to GrpcChannel, e.g. http://localhost. The actual HTTP requests will be redirected to UnixDomainSocketPath by YetAnotherHttpHandler internally.
• When using Kestrel on the server, you need to set the KestrelServerOptions.AllowAlternateSchemes option to true.

Specifying the number of worker threads

YetAnotherHttpHandler's communication processing is run on worker threads of the tokio runtime. The number of worker threads is determined based on the number of CPU cores by default. You can specify a number of worker threads using the YetAnotherHttpHandler.SetWorkerThreads method.

Troubleshoot

System.DllNotFoundException occurs when executing a request on Windows

When attempting to execute a request (yaha_init_runtime), the following exception message may be displayed:

System.DllNotFoundException: Unable to load DLL 'Cysharp.Net.Http.YetAnotherHttpHandler.Native' or one of its dependencies: The specified module could not be found. (0x8007007E)

This may be because the Visual C++ Redistributable Package (vcruntime140.dll) is not installed. Please download and install it from Microsoft's website.

Development

Build & Tests

To debug run in your local environment, you first need to build the native library. Please specify the target as follows when building.

cargo build --target x86_64-pc-windows-msvc

When debugging or running unit tests, the native library is loaded from the following directory.

• native/targets/{arch}-{os}-{toolchain}/{debug,release}/{lib}yaha_native.{dll,so}

When creating a package, The following artifacts directory is used.

• native/artifacts/{.NET RID}/{lib}yaha_native.{dll,so}

# Generate THIRD-PARTY-NOTICES using cargo-about
cargo about generate about.hbs > ../THIRD-PARTY-NOTICES

License

MIT License

This library depends on third-party components. Please refer to THIRD-PARTY-NOTICES for their licenses.