1 files changed, 23 insertions, 10 deletions
diff --git a/rpki/x509.py b/rpki/x509.py
index 99e96d61..61022520 100644
--- a/rpki/x509.py
+++ b/rpki/x509.py
@@ -70,29 +70,41 @@ def looks_like_PEM(text):
   i = text.find("-----BEGIN ")
   return i >= 0 and text.find("\n-----END ", i) > i
 
-def first_rsync_uri(xia):
+def first_uri_matching_prefix(xia, prefix):
   """
-  Find first rsync URI in a sequence of AIA or SIA URIs.
-  Returns the URI if found, otherwise None.
+  Find first URI in a sequence of AIA or SIA URIs which matches a
+  particular prefix string.  Returns the URI if found, otherwise None.
   """
 
   if xia is not None:
     for uri in xia:
-      if uri.startswith("rsync://"):
+      if uri.startswith(prefix):
         return uri
   return None
 
+def first_rsync_uri(xia):
+  """
+  Find first rsync URI in a sequence of AIA or SIA URIs.
+  Returns the URI if found, otherwise None.
+  """
+
+  return first_uri_matching_prefix(xia, "rsync://")
+
 def first_http_uri(xia):
   """
   Find first HTTP URI in a sequence of AIA or SIA URIs.
   Returns the URI if found, otherwise None.
   """
 
-  if xia is not None:
-    for uri in xia:
-      if uri.startswith("http://"):
-        return uri
-  return None
+  return first_uri_matching_prefix(xia, "http://")
+
+def first_https_uri(xia):
+  """
+  Find first HTTPS URI in a sequence of AIA or SIA URIs.
+  Returns the URI if found, otherwise None.
+  """
+
+  return first_uri_matching_prefix(xia, "https://")
 
 def sha1(data):
   """
@@ -508,11 +520,12 @@ class DER_object(object):
   def get_sia_rrdp_notify(self):
     """
     Get SIA RRDP (id-ad-rpkiNotify) URI from this object.
+    We prefer HTTPS over HTTP if both are present.
     Only works for subclasses that support getSIA().
     """
 
     sia = self.get_POW().getSIA()
-    return None if sia is None else first_http_uri(sia[3])
+    return None if sia is None else first_https_uri(sia[3]) or first_http_uri(sia[3])
 
   def get_AIA(self):
     """