Add GuessAuth to authentication methods

build.sh

@@ -12,7 +12,12 @@ _davserver() {
 }
 
 install_build_tests() {
-    $PIP_INSTALL coverage pytest pytest-xprocess git+https://github.com/geier/leif
+    $PIP_INSTALL \
+        coverage \
+        pytest \
+        pytest-xprocess \
+        git+https://github.com/geier/leif \
+        git+https://github.com/sigmavirus24/requests-toolbelt
     _davserver $DAV_SERVER
     if [ "$TRAVIS" = "true" ]; then
         export CFLAGS=-O0  # speed up builds of packages which don't have wheels

example.cfg

@@ -57,9 +57,11 @@ fileext = .vcf
 [storage bob_contacts_remote]
 type = carddav
 url = https://owncloud.example.com/remote.php/carddav/addressbooks/bob/
-# There are two different authentication types: `basic` or `digest`
+# Auth types. If you know yours, set it explicitly for performance.
-#auth = basic
+# - basic
-# For http auth, if empty, no auth will be used
+# - digest
+# - guess (default)
+#auth = guess
 #username =
 # The password can also be fetched from the system password storage or netrc
 #password =
@@ -85,7 +87,7 @@ fileext = .ics
 [storage bob_calendar_remote]
 type = caldav
 url = https://owncloud.example.com/remote.php/caldav/calendars/bob/
-#auth = basic
+#auth = guess
 #username =
 #password =
 #verify = True

tests/storage/dav/servers/radicale/__init__.py

@@ -66,8 +66,7 @@ def do_the_radicale_dance(tmpdir):
     import radicale.auth.http
 
     def is_authenticated(user, password):
-        assert user == 'bob' and password == 'bob'
+        return user == 'bob' and password == 'bob'
-        return True
     radicale.auth.http.is_authenticated = is_authenticated
 
     if storage_backend == 'filesystem':

vdirsyncer/storage/http.py

@@ -16,17 +16,25 @@ USERAGENT = 'vdirsyncer'
 
 
 def prepare_auth(auth, username, password):
+    if username and password:
         if auth == 'basic':
             return (username, password)
         elif auth == 'digest':
             from requests.auth import HTTPDigestAuth
             return HTTPDigestAuth(username, password)
-    elif auth is None:
+        elif auth == 'guess' or auth is None:
-        if username and password:
+            import requests_toolbelt
-            return (username, password)
+            if not hasattr(requests_toolbelt, 'GuessAuth'):
-        return None
+                raise RuntimeError('Your version of requests_toolbelt is too '
+                                   'old.')
+            return requests_toolbelt.GuessAuth(username, password)
         else:
             raise ValueError('Unknown authentication method: {}'.format(auth))
+    elif auth:
+        raise ValueError('For {} authentication, you need to specify username '
+                         'and password.'.format(auth))
+    else:
+        return None
 
 
 def prepare_verify(verify):