Wasi.Sdk
is an experimental package that can build .NET Core projects (including whole ASP.NET Core applications) into standalone WASI-compliant .wasm
files. These can then be run in standard WASI environments or custom WASI-like hosts.
dotnet new console -o MyFirstWasiApp
cd MyFirstWasiApp
dotnet add package Wasi.Sdk --prerelease
dotnet build
You'll see from the build output that this produces bin/Debug/net7.0/MyFirstWasiApp.wasm
.
To run it,
- Ensure you've installed wasmtime and it's available on your system
PATH
- Run your app via
dotnet run
or, if you're using Visual Studio, press Ctrl F5
Alternatively you can invoke runners like wasmtime
or wasmer
manually on the command line. For example,
- For wasmtime, run
wasmtime bin/Debug/net7.0/MyFirstWasiApp.wasm
- For wasmer, run
wasmer bin/Debug/net7.0/MyFirstWasiApp.wasm
Other WASI hosts work similarly.
dotnet new web -o MyWebApp
cd MyWebApp
dotnet add package Wasi.Sdk --prerelease
dotnet add package Wasi.AspNetCore.Server.Native --prerelease
Then:
-
Open your new project in an IDE such as Visual Studio or VS Code
-
Open
Program.cs
and change the linevar builder = WebApplication.CreateBuilder(args)
to look like this:var builder = WebApplication.CreateBuilder(args).UseWasiConnectionListener();
-
Open
Properties/launchSettings.json
and edit theapplicationUrl
value to contain only a single HTTP listener, e.g.,"applicationUrl": "http://localhost:8080"
-
Open your
.csproj
file (e.g., in VS, double-click on the project name) and, inside a<PropertyGroup>
, add this:<WasiRunnerArgs>--tcplisten localhost:8080 --env ASPNETCORE_URLS=http://localhost:8080</WasiRunnerArgs>
Instead of
8080
, you should enter the port number found inProperties\launchSettings.json
.
That's it! You can now run it via dotnet run
(or in VS, use Ctrl F5)
Optionally, to add support for bundling wwwroot
files into the .wasm
file and serving them:
-
Add the NuGet package
Wasi.AspNetCore.BundledFiles
-
In
Program.cs
, replaceapp.UseStaticFiles();
withapp.UseBundledStaticFiles();
-
In your
.csproj
file, add:<ItemGroup> <WasmBundleFiles Include="wwwroot\**" /> </ItemGroup>
Wasi.Sdk
- a package that causes your build to produce a WASI-compliant.wasm
file. This works by:- Downloading the WASI SDK, if you don't already have it
- When your regular .NET build is done, it takes the resulting assemblies, plus the .NET runtime precompiled to WebAssembly, and uses WASI SDK to bundle them into a single
.wasm
file. You can optionally include other native sources such as.c
files in the compilation.
Wasi.AspNetCore.BundledFiles
- providesUseBundledStaticFiles
, and alternative toUseStaticFiles
, that serves static files bundled into your.wasm
file. This allows you to have single-file deployment even if you have files underwwwroot
or elsewhere.Wasi.AspNetCore.Server.Native
- a way of running ASP.NET Core on WASI's TCP-level standard networking APIs (e.g.,sock_accept
). These standards are quite recent and are currently only supported in Wasmtime, not other WASI hosts.
... and more
First, build the runtime. This can take quite a long time.
git submodule update --init --recursive
- Do the following steps using Linux or WSL:
sudo apt-get install build-essential cmake ninja-build python python3 zlib1g-dev
cd modules/runtime/src/mono/wasm
make provision-wasm
(takes about 2 minutes)make build-all
(takes 10-15 minutes)- If you get an error about
setlocale: LC_ALL: cannot change locale
then runsudo apt install language-pack-en
. This only happens on very bare-bones machines.
- If you get an error about
cd ../wasi
make
(takes a few minutes - there are lots of warnings like "System is unknown to cmake" and that's OK)
Now you can build the packages and samples in this repo:
- Prerequisites
- .NET 7 (
dotnet --version
should return7.0.100-preview.4
or later) - Rust and the
wasm32-unknown-unknown
target (technically this is only needed for the CustomHost package)- Install Rust
rustup target add wasm32-unknown-unknown
- .NET 7 (
- Just use
dotnet build
ordotnet run
on any of the samples orsrc
projects, or open the solution in VS and Ctrl F5 on any of the sample projects
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.