WhitelabelResourceController.java

@Controller
@RequestMapping("/whitelabel-resources")
public class WhitelabelResourceController {

    @Autowired
    private WhitelabelService whitelabelService;

    @GetMapping("/logo.png")
    private ResponseEntity getLogo(@AuthenticationPrincipal LoginAuthenticationToken token,
                             @RequestParam(name = "key", required = false) String key) {
        WhitelabelStyling styling = getWhitelabelStyling(token, key);
        byte[] logo = styling.getLogo();
        return ResponseEntity.ok()
                .contentType(MediaType.IMAGE_PNG)
                .cacheControl(CacheControl.maxAge(1, TimeUnit.DAYS))
                .body(logo);
    }

    @GetMapping("/style.css")
    private ResponseEntity getStyle(@AuthenticationPrincipal LoginAuthenticationToken token,
                          @RequestParam(name = "key", required = false) String key) {

        WhitelabelStyling styling = getWhitelabelStyling(token, key);
        String css = styling.getCss();

        return ResponseEntity.ok()
                .contentType(MediaType.valueOf("text/css"))
                .cacheControl(CacheControl.maxAge(1, TimeUnit.DAYS))
                .body(css);
    }

    private WhitelabelStyling getWhitelabelStyling(LoginAuthenticationToken token, String key) {
        WhitelabelStyling styling;

        if (token != null && token.getUser() != null && token.getUser().getWhitelabelStyling() != null) {
            styling = token.getUser().getWhitelabelStyling();
        } else if (key != null) {
            styling = whitelabelService.getWhitelabelStyling(key)
                    .orElseThrow(() -> new IllegalArgumentException("No styling found for key " + key));
        } else {
            throw new IllegalArgumentException("Neither current user's organization has whitelabeling, nor a key was passed");
        }

        return styling;
    }
}