Add HTTP Library for WASM Plugins - go-plugin-http

[hanxi]

Summary

I've implemented an HTTP library for go-plugin that enables WASM plugins to make HTTP requests. Since WASM doesn't support Go's standard net/http package, this library provides HTTP capabilities through host function proxying using the host-function-library pattern.

Repository: https://github.com/hanxi/go-plugin-http

Features

• Provides net/http-like API for WASM plugins (Get, Post, Head, Do, etc.)
• Supports custom headers, request body, and timeout
• Uses the host-function-library pattern (similar to examples/host-function-library)
• Works with Go 1.24+ and -buildmode=c-shared for WASI reactor

Usage Example

Host Side

import (
    httpexport "github.com/hanxi/go-plugin-http/export"
    httpimpl "github.com/hanxi/go-plugin-http/impl"
)

p, err := proto.NewGreeterPlugin(ctx, proto.WazeroRuntime(func(ctx context.Context) (wazero.Runtime, error) {
    r, err := proto.DefaultWazeroRuntime()(ctx)
    if err != nil {
        return nil, err
    }
    // Inject HTTP Library
    return r, httpexport.Instantiate(ctx, r, httpimpl.HttpLibraryImpl{})
}))

Plugin Side

import http "github.com/hanxi/go-plugin-http/plugin"

resp, err := http.Get("https://example.com/api")
if err != nil {
    return nil, err
}
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)

Questions

I think this library could be useful for the go-plugin community. I have two questions:

1. Would you be interested in adding this as an example in examples/?

   • I could submit a PR to add it as examples/http-library or similar

2. Or would you prefer to add a link to this library in the README?

   • Perhaps in a "Community Libraries" or "Related Projects" section

I'm happy to contribute in whatever way works best for the project. Let me know your thoughts!

Related

• This library was inspired by the host-function-library example
• Tested with go-plugin v0.9.0 and wazero v1.11.0

[inliquid]

Hi, go-plugin already supports importing and using host functions such as the ones you mentioned here for HTTP Get, Post, etc. Have you looked through it in examples? What is the main difference with your code and why it should become part of go-plugin itself?

[hanxi]

Yes, I implemented it by referring to your example. Is there something like an officially styled Go library that acts as a secondary abstraction or collection repository—similar to net/http? If the abstraction is done well, would users be able to migrate or switch to another implementation simply by using a replace directive in go.mod? That way, everyone wouldn’t need to re-implement it from scratch.

[hanxi]

Or alternatively, something like the fs package, where the implementation lives at the wazero runtime level.