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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) function that takes a Hono app and returns a WASI-compatible handler function.
  • When a request comes in, it converts the WASI HTTP request into a standard Web Request object.
  • The Hono app processes the request and returns a standard Web Response.
  • The adapter reads the response status, headers, and streams the response body (if present) back to the WASI HTTP provider, ensuring compatibility with both text and binary responses.
  • 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.