Deno.serve QRCode Server Example for All

[suchislife801]

The following code snippet serves a QRCode using Deno.

URL Params Example:

http://localhost:4000/?d=Hello+World!&v=5&e=L&s=250&m=Byte

import { qrcode } from "https://deno.land/x/qrcode/mod.ts";
import { decodeBase64 } from "https://deno.land/[email protected]/encoding/base64.ts";

// Deno.serve() handler
async function handler(request: Request, connInfo: Deno.ServeHandlerInfo): Promise<Response> {

  // Information for a HTTP request.
  const remoteAddr = connInfo.remoteAddr;

  const url = new URL(request.url);
  // Data to encode...
  const d = url.searchParams.get("d") || "Hello World!";
  // Version of barcode 0 (Automatic type number) - 40
  // https://www.qrcode.com/en/about/version.html
  const v = Math.min(40, Math.max(0, Number(url.searchParams.get("v")) || 0));
  // Error Correction L = 7% | M = 15% | Q = 25% | H = 30%
  const e = ["L", "M", "Q", "H"].includes(url.searchParams.get("e")) ? url.searchParams.get("e") : "M";
  // Size of barcode 250 - 500
  const s = Math.min(500, Math.max(250, Number(url.searchParams.get("s")) || 250));
  // Mode = 'Numeric' | 'Alphanumeric' | 'Byte' | 'Kanji'
  const m = ['Numeric', 'Alphanumeric', 'Byte', 'Kanji'].includes(url.searchParams.get("m")) ? url.searchParams.get("m") : "Byte";

  const base64Image = await qrcode(d, { typeNumber: v, errorCorrectLevel: e, size: s, mode: m }); // data:image/gif;base64,...
  const binaryImage = new Uint8Array(decodeBase64(base64Image.split(",")[1]));

  return new Response(binaryImage, {
    status: 200,
    headers: {
      "Server": `Deno v${Deno.version.deno}`,
      "Allow": "HEAD, GET, OPTIONS",
      "Cache-Control": "no-store",
      "Content-Language": "en-US",
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "HEAD, GET, OPTIONS",
      "Access-Control-Allow-Headers": "Content-Type",
      "Access-Control-Allow-Credentials": "false",
      "Content-Type": "image/gif",
    },
  })

}

// Start the QRCode server of Port 4000
Deno.serve({
  port: 4000,
  hostname: "0.0.0.0",
  onListen({ port, hostname }) {
    console.log(`Application..... QR Code - Model 2 - A QR Code Model 2 Server
Deno v${Deno.version.deno} : Typescript v${Deno.version.typescript} : V8 v${Deno.version.v8}
Permissions..... --allow-net
Gateway URL..... http://${hostname}:${port}\n\n`);
  },
  onError(error: unknown) {
    console.error(error);
    return new Response("HTTP 500: Internal Server Error", {
      status: 500,
      headers: { "Content-Type": "text/plain" },
    });
  },
}, handler);

// deno run --allow-net qrServe.ts

Hello World!

[JJ]

So you want to create a PR for this?

[suchislife801]

Hmmm... well, I'm not sure the code I'm showcasing "can be" part of this library as it is a server after all.

I just saw a few posts wondering what can be done with this library, some looking for documentation even so I took a dive into the source code and eventually concluded most people are going want this as a micro-service.

What are your thoughts?

[JJ]

Well, it can be somewhere else, in an examples directory, for instance.

[suchislife801]

Sounds good. I'll polish a little more and post a url safe working example.

I'm working on an HTMX example as well.