identify invalid URL vs. perfect URL

plus HTTPS

chatcommands.py

@@ -1446,7 +1446,7 @@ def report_posts(urls, reported_by, reported_in=None, blacklist_by=None, operati
     normalized_urls = []
     for url in urls:
         t = url_to_shortlink(url)
-        if t == url:
+        if not t:
             normalized_urls.append("That does not look like a valid post URL.")
         elif t not in normalized_urls:
             normalized_urls.append(t)
@@ -1548,7 +1548,9 @@ def report_posts(urls, reported_by, reported_in=None, blacklist_by=None, operati
 
 @command(str, str, privileged=True, whole_msg=True)
 def feedback(msg, post_url, feedback):
-    post_url = url_to_shortlink(post_url)[5:]
+    post_url = url_to_shortlink(post_url)[6:]
+    if not post_url:
+        raise CmdException("No such feedback.")
 
     for feedbacks in (TRUE_FEEDBACKS, FALSE_FEEDBACKS, NAA_FEEDBACKS):
         if feedback in feedbacks:

parsing.py

@@ -219,15 +219,15 @@ def get_user_from_list_command(cmd):  # for example, !!/addblu is a list command
 def url_to_shortlink(url):
     id_and_site = fetch_post_id_and_site_from_url(url)
     if id_and_site is None:
-        return url
+        return None
     if id_and_site[2] == "question":
-        return "http://{}/questions/{}".format(id_and_site[1], id_and_site[0])
+        return "https://{}/questions/{}".format(id_and_site[1], id_and_site[0])
         # We're using "/questions" and not "/q" here because when the URL
         # is made protocol-relative, /q would redirect to http even if the
         # shortlink is https. Same for /a. But there we still use /a because
         # there is no /answers or something like that.
     else:
-        return "http://{}/a/{}".format(id_and_site[1], id_and_site[0])
+        return "https://{}/a/{}".format(id_and_site[1], id_and_site[0])
 
 
 # noinspection PyMissingTypeHints