Simple HTTP web server

Concepts

  • Use Deno’s integrated HTTP server to run your own web server.

Overview

With just a few lines of code you can run your own HTTP web server with control over the response status, request headers and more.

Sample web server

In this example, the user-agent of the client is returned to the client:

webserver.ts:

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

5. // Connections to the server will be yielded up as an async iterable.
6. for await (const conn of server) {
7. // In order to not be blocking, we need to handle each connection individually
8. // without awaiting the function
9. serveHttp(conn);
10. }

12. async function serveHttp(conn: Deno.Conn) {
13. // This "upgrades" a network connection into an HTTP connection.
14. const httpConn = Deno.serveHttp(conn);
15. // Each request sent over the HTTP connection will be yielded as an async
16. // iterator from the HTTP connection.
17. for await (const requestEvent of httpConn) {
18. // The native HTTP server uses the web standard `Request` and `Response`
19. // objects.
20. const body = `Your user-agent is:\n\n${
21. requestEvent.request.headers.get("user-agent") ?? "Unknown"
22. }`;
23. // The requestEvent's `.respondWith()` method is how we send the response
24. // back to the client.
25. requestEvent.respondWith(
26. new Response(body, {
27. status: 200,
28. }),
29. );
30. }
31. }

Then run this with:

1. deno run --allow-net webserver.ts

Then navigate to http://localhost:8080/ in a browser.

Using the std/http library

ℹ️ Since the stabilization of native HTTP bindings in ^1.13.x, std/http now supports a native HTTP server from ^0.107.0. The legacy server module was removed in 0.117.0.

webserver.ts:

1. import { serve } from "https://deno.land/std@$STD_VERSION/http/server.ts";

3. const port = 8080;

5. const handler = (request: Request): Response => {
6. const body = `Your user-agent is:\n\n${
7. request.headers.get("user-agent") ?? "Unknown"
8. }`;

10. return new Response(body, { status: 200 });
11. };

13. console.log(`HTTP webserver running. Access it at: http://localhost:8080/`);
14. await serve(handler, { port });

Then run this with:

1. deno run --allow-net webserver.ts