confirmation: Move check_prereg_key_and_redirect to registration.py.

zerver/views/registration.py

@@ -47,6 +47,26 @@ import ujson
 
 import urllib
 
+def check_prereg_key_and_redirect(request: HttpRequest, confirmation_key: str) -> HttpResponse:
+    # If the key isn't valid, show the error message on the original URL
+    confirmation = Confirmation.objects.filter(confirmation_key=confirmation_key).first()
+    if confirmation is None or confirmation.type not in [
+            Confirmation.USER_REGISTRATION, Confirmation.INVITATION, Confirmation.REALM_CREATION]:
+        return render_confirmation_key_error(
+            request, ConfirmationKeyException(ConfirmationKeyException.DOES_NOT_EXIST))
+    try:
+        get_object_from_key(confirmation_key, confirmation.type)
+    except ConfirmationKeyException as exception:
+        return render_confirmation_key_error(request, exception)
+
+    # confirm_preregistrationuser.html just extracts the confirmation_key
+    # (and GET parameters) and redirects to /accounts/register, so that the
+    # user can enter their information on a cleaner URL.
+    return render(request, 'confirmation/confirm_preregistrationuser.html',
+                  context={
+                      'key': confirmation_key,
+                      'full_name': request.GET.get("full_name", None)})
+
 @require_post
 def accounts_register(request: HttpRequest) -> HttpResponse:
     key = request.POST['key']