How to Build a One-Time QR Code with URL Redirect
Requirement https://t.me/blacktechsharing/183161 Approach A QR code is essentially a string of characters embedded in an image. This string can be a URL. Since the QR code image has already been sent to others, and you can't go to their computer or phone to delete the image, how is a "one-time QR code" implemented? If the QR code image stays the same, then the URL A corresponding to the QR code stays the same. When you visit URL A, you're accessing a server. This server can make everyone who visits URL A redirect to a new URL B. We define URL B as the URL that actually carries the real meaning. We let the server allow only the first visitor to URL A to be redirected to URL B; subsequent visits to URL A will have the redirection disabled. This is how a "one-time QR code" is implemented.