Test cases for the server; fix infinite loop in resolver

1 files changed, 11 insertions, 6 deletions

diff --git a/project2/proj2_s4498062/dns/resolver.py b/project2/proj2_s4498062/dns/resolver.py
index 4c09681..8bd7bb9 100644
--- a/project2/proj2_s4498062/dns/resolver.py
+++ b/project2/proj2_s4498062/dns/resolver.py
@@ -82,12 +82,14 @@ class Resolver(object):
     def do_query_to_multiple(
             self, hints, hostname, type_, class_=Class.IN, caching=True):
         """Do a query to multiple hints, return the remaining hints"""
+        seen = []
         while hints != []:
             hint = hints.pop()
+            seen.append(hint)
             response = self.do_query(hint, hostname, type_, class_, caching)
             if response is not None:
-                return hints, response
-        return [], []
+                return seen, hints, response
+        return seen, [], []
 
     def gethostbyname(self, hostname):
         """ Translate a host name to IPv4 address.
@@ -108,15 +110,18 @@ class Resolver(object):
             for cname in cnames:
                 cname, aliases, addrs = self.gethostbyname(cname.rdata.data)
                 if addrs != []:
-                    return str(cname), aliases, addrs
+                    return str(cname), list(set(aliases)), list(set(addrs))
 
         if hostname == '':
             return hostname, [], []
 
+        seen = []
         hints = self.ROOT_SERVERS[:]
         aliases = []
         while hints != []:
-            hints, info = self.do_query_to_multiple(hints, hostname, Type.A)
+            used, hints, info = self.do_query_to_multiple(
+                hints, hostname, Type.A)
+            seen += used
 
             aliases += [
                 r.rdata.data for r in info
@@ -137,11 +142,11 @@ class Resolver(object):
                 add.rdata.data for ns in auths for add in info
                 if add.match(name=ns, type_=Type.A)]
             if ips != []:
-                hints += ips
+                hints += [ip for ip in ips if ip not in seen]
                 continue
             if auths != []:
                 auths = [h for a in auths for h in self.gethostbyname(a)[2]]
-                hints += auths
+                hints += [auth for auth in auths if auth not in seen]
                 continue
 
             # Case 3: aliases