Refactor the authentication handling

Instead of trying to abstract the authentication away from the client,
allow the client to provide the authentication handler.

Implement simple handlers for HTTP basic and digest authentication with
credentials from netrc.

Change-Id: Icd6c7d359ecbd441308bc6f67fd19c7f55ebcb8f

2 files changed, 74 insertions, 35 deletions

diff --git a/pygerrit/rest/__init__.py b/pygerrit/rest/__init__.py
index 0d24794..99364e1 100644
--- a/pygerrit/rest/__init__.py
+++ b/pygerrit/rest/__init__.py
@@ -23,36 +23,13 @@
 """ Interface to the Gerrit REST API. """
 
 import json
+import logging
 import requests
 
 GERRIT_MAGIC_JSON_PREFIX = ")]}\'\n"
 GERRIT_AUTH_SUFFIX = "/a"
 
 
-class GerritRestAPIAuthentication(requests.auth.HTTPDigestAuth):
-
-    """ HTTP Digest Auth with netrc credentials. """
-
-    def __init__(self, url, username=None, password=None):
-        self.username = username
-        self.password = password
-        if not self.has_credentials():
-            (self.username, self.password) = \
-                requests.utils.get_netrc_auth(url)
-        if self.has_credentials():
-            super(GerritRestAPIAuthentication, self).__init__(self.username,
-                                                              self.password)
-
-    def __call__(self, req):
-        if (self.username and self.password):
-            req = super(GerritRestAPIAuthentication, self).__call__(req)
-        return req
-
-    def has_credentials(self):
-        """ Return True if authentication credentials are present. """
-        return (self.username is not None and self.password is not None)
-
-
 class GerritRestAPIError(Exception):
 
     """ Raised when an error occurs during Gerrit REST API access. """
@@ -97,33 +74,35 @@ class GerritRestAPI(object):
 
     """ Interface to the Gerrit REST API. """
 
-    def __init__(self, url, username=None, password=None):
+    def __init__(self, url, auth=None):
         """ Constructor.
 
         `url` is assumed to be the full URL to the server, including the
         'http(s)://' prefix.
 
-        HTTP digest authentication is used with the given `username` and
-        `password`.  If both are not given, an attempt is made to get them
-        from the netrc file.  If that fails, anonymous access is used and
-        functionality is limited.
+        If `auth` is specified, it must be a derivation of the `AuthBase`
+        class from the `requests` module.  The `url` will be adjusted if
+        necessary to make sure it includes Gerrit's authentication suffix.
 
         """
-        self.kwargs = {}
-        self.url = url
+        self.kwargs = {'auth': auth}
+        self.url = url.rstrip('/')
         self.session = requests.session()
 
-        self.url = url.rstrip('/')
-        auth = GerritRestAPIAuthentication(url, username, password)
-        if auth.has_credentials():
-            self.kwargs['auth'] = auth
+        if auth:
+            if not isinstance(auth, requests.auth.AuthBase):
+                raise GerritRestAPIError('Invalid auth type; must be derived '
+                                         'from requests.auth.AuthBase')
+
             if not self.url.endswith(GERRIT_AUTH_SUFFIX):
                 self.url += GERRIT_AUTH_SUFFIX
         else:
             if self.url.endswith(GERRIT_AUTH_SUFFIX):
                 self.url = self.url[: - len(GERRIT_AUTH_SUFFIX)]
+
         if not self.url.endswith('/'):
             self.url += '/'
+        logging.debug("url %s", self.url)
 
     def make_url(self, endpoint):
         """ Make the necessary url from `endpoint`.
diff --git a/pygerrit/rest/auth.py b/pygerrit/rest/auth.py
new file mode 100644
index 0000000..01147af
--- /dev/null
+++ b/pygerrit/rest/auth.py
@@ -0,0 +1,60 @@
+# The MIT License
+#
+# Copyright 2013 Sony Mobile Communications. All rights reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+""" Authentication classes. """
+
+from requests.auth import HTTPDigestAuth, HTTPBasicAuth
+from requests.utils import get_netrc_auth
+
+from . import GerritRestAPIError
+
+
+class HTTPDigestAuthFromNetrc(HTTPDigestAuth):
+
+    """ HTTP Digest Auth with netrc credentials. """
+
+    def __init__(self, url):
+        auth = get_netrc_auth(url)
+        if not auth:
+            raise GerritRestAPIError("netrc missing or no credentials found "
+                                     "in netrc")
+        username, password = auth
+        super(HTTPDigestAuthFromNetrc, self).__init__(username, password)
+
+    def __call__(self, req):
+        return super(HTTPDigestAuthFromNetrc, self).__call__(req)
+
+
+class HTTPBasicAuthFromNetrc(HTTPBasicAuth):
+
+    """ HTTP Basic Auth with netrc credentials. """
+
+    def __init__(self, url):
+        auth = get_netrc_auth(url)
+        if not auth:
+            raise GerritRestAPIError("netrc missing or no credentials found "
+                                     "in netrc")
+        username, password = auth
+        super(HTTPBasicAuthFromNetrc, self).__init__(username, password)
+
+    def __call__(self, req):
+        return super(HTTPBasicAuthFromNetrc, self).__call__(req)