HTTP server: File based Routing

If you've used frameworks like Next.js, you might be familiar with file based routing. You add a file in a specific directory and it automatically becomes a route. This example demonstrates how to create a simple HTTP server that uses file based routing. Note: This is not an exhaustive example and is meant to be a starting point. Permissions required: `--allow-net`: To start the HTTP server. `--allow-read`: To read files from the file system for dynamic import.

Edit on Github

This is a simple module that exports a `GET` handler for the /users route. You may implement other HTTP methods such as `POST`, `PUT`, and `DELETE` in this file.

./users.ts

export function GET(_req: Request): Response {
  return new Response("Hello from user.ts", { status: 200 });
}

This is the main file that will be used to route requests.

./main.ts

async function handler(req: Request): Promise {

Extract the path and method from the request.

./main.ts

  const url = new URL(req.url);

`path` could be any valid URL path such as /users, /posts, etc. For paths like `/users`, the file `./users.ts` will be imported. However, deeper paths like `/org/users` will require a file `./org/users.ts`. So, you can create nested routes by creating nested directories and files.

./main.ts

  const path = url.pathname;

method could be any of the HTTP methods such as GET, POST, PUT, DELETE, etc.

./main.ts

  const method = req.method;
  let module;
  try {

Dynamically import the module based on the path. Notice the `.` prefix before the path. The path is relative to the current file. Be aware of caveats when using dynamic imports. [Read more](https://docs.deno.com/deploy/api/dynamic-import)

./main.ts

    module = await import(`.${path}.ts`);
  } catch (_error) {

If the module is not found, return a 404 response.

./main.ts

    return new Response("Not found", { status: 404 });
  }

Check if the module has the method handler.

./main.ts

  if (module[method]) {

Call the method handler with the request.

./main.ts

    return module[method](req);
  }

If the method handler is not found, return a 501:Not Implemented response.

./main.ts

  return new Response("Method not implemented", { status: 501 });
}

Start the server on the default port.

./main.ts

Deno.serve(handler);

Run this example locally using the Deno CLI:

deno run --allow-net --allow-read https://docs.deno.com/examples/http-server-file-router.ts/main

HTTP server: File based Routing

Additional resources