Ticket Qrcode Endpoint

In this lesson, we implement the endpoint to get the QR code image.

Creating the QR Code Endpoint

We'll add a new endpoint to the TicketController that returns a QR code image associated with a specific ticket.

The endpoint will be an extension of the existing get ticket functionality:

@GetMapping(path = "/{ticketId}/qr-codes")
public ResponseEntity<byte[]> getTicketQrCode(
    @AuthenticationPrincipal Jwt jwt,
    @PathVariable UUID ticketId
) {
    byte[] qrCodeImage = qrCodeService.getQrCodeImageForUserAndTicket(
        parseUserId(jwt),
        ticketId
    );

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.IMAGE_PNG);
    headers.setContentLength(qrCodeImage.length);

    return ResponseEntity.ok()
        .headers(headers)
        .body(qrCodeImage);
}

HTTP Headers for Image Response

To properly serve the QR code image, we need to set specific HTTP headers:

We set the Content-Type header to image/png since we're returning a PNG image
We set the Content-Length header to match the size of our image data in bytes

These headers help the client browser understand how to handle and display the received data correctly.

Summary

Implemented the get QR Code endpoint