Added easier to detect error message when search returns 0 results. T…

…his currently parses html result from the mailarchive system, but when we get proper API to mailarchive system it should be changed to do that instead. Fixes #2126. Commit ready for merge.

 - Legacy-Id: 15706

ietf/doc/views_review.py

@@ -687,7 +687,10 @@ def search_mail_archive(request, name, request_id):
     try:
         res["messages"] = mailarch.retrieve_messages(res["query_data_url"])[:MAX_RESULTS]
     except Exception as e:
-        res["error"] = "Retrieval from mail archive failed: {}".format(unicode(e))
+        if unicode(e) == "NONE":
+            res["error"] = "No results found"
+        else:
+            res["error"] = "Retrieval from mail archive failed: {}".format(unicode(e))
         # raise # useful when debugging
 
     return JsonResponse(res)

ietf/review/mailarch.py

@@ -4,6 +4,7 @@
 import datetime, tarfile, mailbox, tempfile, hashlib, base64, email.utils
 import urllib
 import urllib2, contextlib
+import re
 
 from django.conf import settings
 
@@ -92,6 +93,9 @@ def retrieve_messages(query_data_url):
     with contextlib.closing(urllib2.urlopen(query_data_url, timeout=15)) as fileobj:
         content_type = fileobj.info()["Content-type"]
         if not content_type.startswith("application/x-tar"):
+            if content_type.startswith("text/html"):
+                if not re.search("no-results", fileobj.read(20000)) is None:
+                    raise Exception("NONE")
             raise Exception("Export failed - this usually means no matches were found")
 
         with tarfile.open(fileobj=fileobj, mode='r|*') as tar: