Examples

A collection of code examples demonstrating certain functions of Deno Deploy.

Hello World

CLI

Deploy

HTTP

A HTTP server that responds with a static "Hello World" string to all requests.

Open Editor
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";

function handler(_req: Request): Response {
  return new Response("Hello, World");
}

serve(handler);

Respond with JSON

CLI

Deploy

HTTP

A HTTP server that responds to requests with pretty printed JSON.

Open Editor
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";

function handler(_req: Request) {
  const data = {
    Hello: "World!",
  };
  const body = JSON.stringify(data, null, 2);
  return new Response(body, {
    headers: { "content-type": "application/json; charset=utf-8" },
  });
}

serve(handler);

Redirects

CLI

Deploy

HTTP

A HTTP server that that redirects users to https://example.com

Open Editor
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";

function handler(_req: Request) {
  return Response.redirect("https://example.com", 307);
}

serve(handler);

Get client IP address

CLI

Deploy

HTTP

A HTTP server that responds to requests with the client's IP address.

Open Editor
function handler(_req: Request, connInfo: Deno.ServeHandlerInfo) {
  const addr = connInfo.remoteAddr;
  const ip = addr.hostname;
  return new Response(`Your IP address is <b>${ip}</b>`, {
    headers: { "content-type": "text/html" },
  });
}

Deno.serve(handler);

Handling <form> submissions

CLI

Deploy

HTTP

A HTTP server that serves a HTML form and handles the form submission via a POST request.

Open Editor
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";

const html = `
<form method="POST" action="/">
  <input type="text" name="name" placeholder="Your name">
  <button type="submit">Submit</button>
</form>
`;

async function handler(req: Request): Promise<Response> {
  switch (req.method) {
    case "GET": {
      return new Response(html, {
        headers: { "content-type": "text/html; charset=utf-8" },
      });
    }

    case "POST": {
      const body = await req.formData();
      const name = body.get("name") || "anonymous";
      return new Response(`Hello ${name}!`);
    }

    default:
      return new Response("Invalid method", { status: 405 });
  }
}

serve(handler);

Proxying to other servers

CLI

Deploy

HTTP

A HTTP server that proxies requests to a different server.

Open Editor
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";

async function handler(req: Request): Promise<Response> {
  const url = new URL(req.url);
  url.protocol = "https:";
  url.hostname = "example.com";
  url.port = "443";
  return await fetch(url.href, {
    headers: req.headers,
    method: req.method,
    body: req.body,
  });
}

serve(handler);

Server side rendering with JSX

CLI

Deploy

HTTP

A HTTP server that renders a HTML page on the server with JSX (using Preact).

Open Editor
/** @jsx h */
import { serve } from "https://deno.land/std@0.140.0/http/server.ts";
import { h } from "https://esm.sh/preact@10.5.15";
import { renderToString } from "https://esm.sh/preact-render-to-string@5.1.19?deps=preact@10.5.15";

function handler(_req: Request): Response {
  const page = (
    <div>
      <h1>Current time</h1>
      <p>{new Date().toLocaleString()}</p>
    </div>
  );
  const html = renderToString(page);
  return new Response(html, {
    headers: { "content-type": "text/html; charset=utf-8" },
  });
}

serve(handler);

Wildcard Domain

CLI

Deploy

HTTP

A HTTP server that serves a wildcard domain.

Open Editor
import { serve } from "https://deno.land/std@0.155.0/http/server.ts";

function handler(req: Request) {
  const url = new URL(req.url);
  if (url.hostname === "a.example.com") {
    return new Response("website 1");
  } else if (url.hostname === "b.example.com") {
    return new Response("website 2");
  }
  return new Response("website infinity");
}

serve(handler);