Fix HTTP Auth failure with old (pre UTF-8) servers

Some servers, like really old SabreDAV based servers, seem to choke on
password if we pass a bytes sequence instead of a string to the
"requests" libraries HTTPDigestAuth object.

This Fix retries authentication in case of authentication failure with
the same password as plain string (which, in Python3 is anyway UTF-8).

Refreshed to address review comments.

1 files changed, 22 insertions, 0 deletions

diff --git a/caldav/davclient.py b/caldav/davclient.py
index 14ac40d..98dadcb 100644
--- a/caldav/davclient.py
+++ b/caldav/davclient.py
@@ -545,6 +545,28 @@ class DAVClient:
                 self.auth = requests.auth.HTTPDigestAuth(self.username, self.password)
             else:
                 raise NotImplementedError("Auth method %s not supported yet" % auth_type)
+            return self.request(url, method, body, headers)
+
+        elif (r.status_code == 401 and
+            'WWW-Authenticate' in r.headers and
+            self.password and
+            self.username and
+            self.auth):
+
+            ## Some (ancient) servers don't like UTF-8 binary auth with Digest authentication.
+            ## An example are old SabreDAV based servers.  Not sure about UTF-8 and Basic Auth,
+            ## but likely the same.  so retry if password is a bytes sequence and not a string
+            ## (see commit 13a4714, which introduced this regression)
+
+            auth_type = r.headers['WWW-Authenticate']
+            auth_type = auth_type[0:auth_type.find(" ")]
+
+            if hasattr(self.password, 'decode'):
+                if auth_type == 'Basic':
+                    self.auth = requests.auth.HTTPBasicAuth(self.username, self.password.decode())
+                elif auth_type == 'Digest':
+                    self.auth = requests.auth.HTTPDigestAuth(self.username, self.password.decode())
+
             self.username = None
             self.password = None
             return self.request(url, method, body, headers)