Use Extism PDK for .Net to send HTTP(s) requests from inside WASM

This devcontainer is configured to provide you a DotNet SDK 8.0 and wasi-sdk 20.0.

Instructions for this devcontainer

Preparation

1. Open this repo in devcontainer, e.g. using Github Codespaces. Type or copy/paste following commands to devcontainer's terminal.

2. Install the WASI workload:

dotnet workload install wasi-experimental

3. Generate WASI-enabled .Net project:

dotnet new wasiconsole -o HTTPRequestingPlugin

4. cd into that project's directory:

cd HTTPRequestingPlugin

5. Add Extism PDK dependency to project:

dotnet add package Extism.Pdk --prerelease

6. Patch project configuration to produce solid standalone WASM file ( info ):

sed -si.bak 's|<PublishTrimmed>true</PublishTrimmed>|& \n\n<WasmSingleFileBundle>true</WasmSingleFileBundle>\n<WasmBuildNative>true</WasmBuildNative>\n|' HTTPRequestingPlugin.csproj 

7. Copy HTTP example source code into project's folder to replace generated one:

cp ../Program.cs . 

Building

1. Compile the example:

dotnet build

Build process creates 25M-sized HTTPRequestingPlugin/bin/Debug/net8.0/wasi-wasm/AppBundle/HTTPRequestingPlugin.wasm bundle.

Test with Extism CLI

For testing purposes, you can invoke functions from Extism plugins with Extism CLI.

1. Install Extism CLI from Github releases:

wget https://github.com/extism/cli/releases/download/v0.3.0/extism-v0.3.0-linux-amd64.tar.gz
tar -xzf extism-v0.3.0-linux-amd64.tar.gz

And now you have extism binary in current folder.

2. Run default function (it's _start) from extism plugin with CLI, allowing outbound connections to all hosts:

./extism call ./bin/Debug/net8.0/wasi-wasm/AppBundle/HTTPRequestingPlugin.wasm _start --allow-host '*' --wasi

Finish

Perform your own experiments if desired.

---

This devcontainer is based on dev-wasm/dev-wasm-dotnet.

_{Created for (wannabe-awesome) list}