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Version: 1.x

HTTP Server with Hono

This example demonstrates how to use hono with a custom adapter that works with the wasi:http interface. The hono library is a lightweight and fast web framework for building HTTP servers. See the hono documentation for more details.

Additionally, it makes use of the wasi:logging/logging to log details about incoming requests and responses with a hono middleware and it uses the wasi:config/runtime to pass config from the environment to the hono app as part of the env key on the request context.

Setup​

  1. Install dependencies:

    bash
    npm install

  2. Build the project:

    bash
    npm run build

  3. Start the server:

    bash
    npm start

Overview​

App​

This component implements the wasi:http/incoming-handler interface, as defined in its WIT (WebAssembly Interface Types) world.

Adapter​

The adapter in src/wasmcloud/hono-adapter bridges the gap between the hono web framework and the wasi:http interface. It converts incoming WASI HTTP requests into standard Web Request objects that Hono can process, and then transforms the Hono Response back into a WASI-compatible response. This allows you to use Hono's familiar routing and middleware patterns in a Wasm Component, just like you would in a Node.js or edge environment.

How it works:

  • The adapter exposes a serve(app: Hono) function that takes a Hono app and adds a 'fetch' event-listener onto the global context. JCO componentize-js supports this (through StarlingMonkey) by automatically adding the necessary imports.
  • Any errors in the request handling are caught and a 500 Internal Server Error is returned to the client.

Logging Middleware​

The logging middleware in src/wasmcloud/hono-middleware-wasi-logging provides request and response logging for your Hono app using the wasi:logging/logging interface. It logs details about each incoming request and outgoing response, such as method, path, status code, and duration, to the wasmCloud host's log system.

How it works:

  • Attaches to your Hono app as middleware
  • Logs request details before passing to the next handler
  • Logs response details (including status and timing) after the handler completes
  • Uses the WASI logging interface for compatibility with wasmCloud and other WASI hosts

This makes it easy to observe and debug your HTTP component's behavior in production or development environments.

Environment Variables​

The example uses the wasi:config/runtime interface to pass environment variables to the Hono app. The env object is available in the request context, allowing you to access configuration values in your routes and middleware.