From ab037a07650aeee638961fc23c085370c5cb9889 Mon Sep 17 00:00:00 2001
From: anthonybaxter <anthonybaxter@gmail.com>
Date: Tue, 6 Jul 2021 11:50:12 +1000
Subject: [PATCH] Add a warning if a server sends back non-XML

https://data.csiro.au/dap/ws/v2/collections is an example of a server that sends back JSON rather than XML to a sickle request by
default.

Adding headers={'Accept': 'application/xml'} to the Sickle() constructor fixes that, but it was a bit of digging to work out why. This
logging message would have saved me a bit of debugging time.
---
 sickle/response.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sickle/response.py b/sickle/response.py
index 76f6897..af07365 100644
--- a/sickle/response.py
+++ b/sickle/response.py
@@ -6,6 +6,7 @@
     :copyright: Copyright 2015 Mathias Loesch
 """
 
+import logging
 from lxml import etree
 
 XMLParser = etree.XMLParser(remove_blank_text=True, recover=True, resolve_entities=False)
@@ -34,6 +35,10 @@ def raw(self):
     @property
     def xml(self):
         """The server's response as parsed XML."""
+        if (self.http_response.headers.get('Content-Type') !=
+            'application/xml'):
+            logging.warn('received non-XML response %s',
+                         self.http_response.headers.get('Content-Type'))
         return etree.XML(self.http_response.content,
                          parser=XMLParser)