How can I check if a server exists in Emacs Lisp

I am writing a function that tests for brokens links in an org-mode buffer:

    (setq urls '("http://google.com" "http://bing.com" "http://www.yahoo.com"  "http://thisdoesntexist.net"))
    (while (setq nextlink (car urls))
      (if (url-http-file-exists-p nextlink)
          (message "Link works: %s" nextlink)
        (message "Broken Link found: %s" nextlink))
      (setq urls (cdr urls)))

This works except when it encounters a non-existent web server. Then it throws a lisp error and opens up a backtrace buffer.

What I would like is way to first test if the server exists and if so then use url-http-file-exists-p to check for a specific document.

Thanks

• Edited to add sol开发者_如何学编程ution that works for me. Thanks Dov!

  (while (setq nextlink (car urls))
    (condition-case nil
      (if (url-http-file-exists-p nextlink)
          (message "Link works: %s" nextlink)
        (message "Broken Link found: %s" nextlink))
      ((error) (message "Server not found: %s" nextlink)))
      (setq urls (cdr urls)))
  

Why don't you just catch the error through an exception handling condition-case block?