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HTTP ​

The following basic examples demonstrate common use cases for simple HTTP servers.

Respond with text ​

An HTTP server using the std/http module that responds with "Hello world!" string.

CLI Netzo

ts
import { serve } from "https://deno.land/[email protected]/http/server.ts"

function handler(_req: Request): Response {
  return new Response("Hello world!")
}

serve(handler)
import { serve } from "https://deno.land/[email protected]/http/server.ts"

function handler(_req: Request): Response {
  return new Response("Hello world!")
}

serve(handler)

Deprecated Service Worker API

The fetch event and respondWith method were previously supported but have been deprecated in favor of the serve() function from std/http module (or equivalent) which provides more control over the server to handle HTTP requests.

ts
// @deprecated - use `serve()` of the std/http module (or equivalent) instead
addEventListener('fetch', (event: FetchEvent) => {
  event.respondWith(new Response('Hello world!'))
})
// @deprecated - use `serve()` of the std/http module (or equivalent) instead
addEventListener('fetch', (event: FetchEvent) => {
  event.respondWith(new Response('Hello world!'))
})

Respond with JSON ​

An HTTP server using the std/http module that responds to requests with JSON.

CLI Netzo

ts
import { serve } from "https://deno.land/[email protected]/http/server.ts";

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

serve(handler);
import { serve } from "https://deno.land/[email protected]/http/server.ts";

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

serve(handler);

Using the Response.json(body) short-hand

Instead of manually building and returing a Response object, the return Response.json(body) short-hand can be used to respond directly with JSON. This will automatically stringify the body and set the content-type header to application/json.

ts
function handler(_req: Request): Response {
  const data = { message: 'Hello world!' }
  const body = JSON.stringify(data, null, 2) 
  return new Response(body, { 
    headers: { 'content-type': 'application/json' }, 
  }) 
  return Response.json(data) 
}
function handler(_req: Request): Response {
  const data = { message: 'Hello world!' }
  const body = JSON.stringify(data, null, 2) 
  return new Response(body, { 
    headers: { 'content-type': 'application/json' }, 
  }) 
  return Response.json(data) 
}

Get client IP address ​

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

CLI Netzo

ts
import { ConnInfo, serve } from "https://deno.land/[email protected]/http/server.ts";

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

serve(handler);
import { ConnInfo, serve } from "https://deno.land/[email protected]/http/server.ts";

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

serve(handler);

Proxying to other servers ​

An HTTP server that proxies requests to a different server.

CLI Netzo

ts
import { serve } from "https://deno.land/[email protected]/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);
import { serve } from "https://deno.land/[email protected]/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);

Wildcard Domain ​

An HTTP server that serves a wildcard domain.

CLI Netzo

ts
import { serve } from "https://deno.land/[email protected]/http/server.ts";

function handler(req: Request): Response {
  const url = new URL(req.url);
  switch (url.hostname) {
    case "en.example.com":
      return new Response("english");
    case "es.example.com":
      return new Response("español");
    default:
      return new Response("default");
  }
}

serve(handler);
import { serve } from "https://deno.land/[email protected]/http/server.ts";

function handler(req: Request): Response {
  const url = new URL(req.url);
  switch (url.hostname) {
    case "en.example.com":
      return new Response("english");
    case "es.example.com":
      return new Response("español");
    default:
      return new Response("default");
  }
}

serve(handler);

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