webserver.ts

// This is a straight copy/paste from the Deno docs: https://deno.land/manual@v1.31.2/examples/http_server

// Start listening on port 8080 of localhost.
const server = Deno.listen({ port: 8080 });
console.log(`HTTP webserver running.  Access it at:  http://localhost:8080/`);

// Connections to the server will be yielded up as an async iterable.
for await (const conn of server) {
    // In order to not be blocking, we need to handle each connection individually
    // without awaiting the function
    serveHttp(conn);
}

async function serveHttp(conn: Deno.Conn) {
    // This "upgrades" a network connection into an HTTP connection.
    const httpConn = Deno.serveHttp(conn);
    // Each request sent over the HTTP connection will be yielded as an async
    // iterator from the HTTP connection.
    for await (const requestEvent of httpConn) {
        // The native HTTP server uses the web standard `Request` and `Response`
        // objects.
        const body = `Your user-agent is:\n\n${
            requestEvent.request.headers.get("user-agent") ?? "Unknown"
        }`;
        // The requestEvent's `.respondWith()` method is how we send the response
        // back to the client.
        requestEvent.respondWith(
            new Response(body, {
                status: 200,
            }),
        );
    }
}