From ccda170e44d999a4e9c6851a5b3a2ec7ccc63e9e Mon Sep 17 00:00:00 2001
From: Federico Capoano <nemesis@ninux.org>
Date: Mon, 21 Sep 2015 19:01:11 +0200
Subject: [PATCH] Workaround for OLSRv1 jsoninfo plugin missing HTTP headers

Unfortunately some routing protocols might not add http headers by default
this situation raises an exception with the requests library (Connection Aborted)
to make netdiff easier to use, in these cases we fallback to urllib2 which
handles this issue in a nicer way.
---
 netdiff/parsers/base.py | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/netdiff/parsers/base.py b/netdiff/parsers/base.py
index 72cf7db..043fcce 100644
--- a/netdiff/parsers/base.py
+++ b/netdiff/parsers/base.py
@@ -2,6 +2,12 @@
 import json
 import requests
 import telnetlib
+# python2
+try:
+    from urllib2 import urlopen
+# python3
+except:
+    from urllib.request import urlopen
 
 try:
     import urlparse
@@ -106,15 +112,38 @@ def _get_file(self, path):
 
     def _get_http(self, url):
         try:
-            response = requests.get(url.geturl(),
-                                    verify=self.verify,
-                                    timeout=self.timeout)
+            # unfortunately some routing protocols might not add http headers by default
+            # this situation raises an exception with the requests library (Connection Aborted)
+            # to make netdiff easier to use, in these cases we fallback to urllib2 which
+            # handles this issue in a nicer way
+            try:
+                response = requests.get(url.geturl(),
+                                        verify=self.verify,
+                                        timeout=self.timeout)
+            except Exception as e:
+                # this is the case we want to handle gracefully
+                # and fallback to urllib2
+                if isinstance(e, requests.exceptions.ConnectionError) and 'BadStatusLine' in str(e):
+                    try:
+                        response = urlopen(url.geturl(), timeout=self.timeout)
+                    except Exception as e:
+                        raise TopologyRetrievalError(e)
+                    else:
+                        status_code = response.getcode()
+                        content = response.read()
+                # in all the other cases pass the error to the next handling block
+                else:
+                    raise TopologyRetrievalError(e)
         except Exception as e:
             raise TopologyRetrievalError(e)
+        # save response status and content in vars
+        else:
+            status_code = response.status_code
+            content = response.content.decode()
         if response.status_code != 200:
-            msg = 'Expecting HTTP 200 ok, got {0}'.format(response.status_code)
+            msg = 'Expecting HTTP 200 ok, got {0}'.format(status_code)
             raise TopologyRetrievalError(msg)
-        return response.content.decode()
+        return content
 
     def _get_telnet(self, url):
         try: