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

Tested with Extism .NET PDK v1.0.3, Extism CLI v1.5.1.

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

6. Copy HTTP example source code into project's folder to replace a 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/v1.5.1/extism-v1.5.1-linux-amd64.tar.gz -O /tmp/extism.tar.gz
tar -xzf /tmp/extism.tar.gz -C /tmp ; mv /tmp/extism .

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.

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

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