Code cleaned and modules renamed

*Radicale is probably broken now*

radicale/auth/IMAP.py

@@ -0,0 +1,86 @@
+# -*- coding: utf-8 -*-
+#
+# This file is part of Radicale Server - Calendar Server
+# Copyright © 2012 Daniel Aleksandersen
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Radicale.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+IMAP authentication.
+
+Secure authentication based on the ``imaplib`` module.
+
+Validating users against a modern IMAP4rev1 server that awaits STARTTLS on
+port 143. Legacy SSL (often on legacy port 993) is deprecated and thus
+unsupported. STARTTLS is enforced except if host is ``localhost`` as
+passwords are sent in PLAIN.
+
+Python 3.2 or newer is required for TLS.
+
+"""
+
+import imaplib
+
+from radicale import config, log
+
+IMAP_SERVER = config.get("auth", "imap_auth_host_name")
+IMAP_SERVER_PORT = config.get("auth", "imap_auth_host_port")
+
+
+def is_authenticated(user, password):
+    """Check if ``user``/``password`` couple is valid."""
+
+    log.LOGGER.debug(
+        "[IMAP AUTH] Connecting to %s:%s." % (IMAP_SERVER, IMAP_SERVER_PORT,))
+    connection = imaplib.IMAP4(host=IMAP_SERVER, port=IMAP_SERVER_PORT)
+
+    server_is_local = (IMAP_SERVER == "localhost")
+
+    connection_is_secure = False
+    try:
+        connection.starttls()
+        log.LOGGER.debug("IMAP server connection changed to TLS.")
+        connection_is_secure = True
+    except AttributeError:
+        if not server_is_local:
+            log.LOGGER.error(
+                "Python 3.2 or newer is required for IMAP + TLS.")
+    except (imaplib.IMAP4.error, imaplib.IMAP4.abort) as exception:
+        log.LOGGER.warning(
+            "IMAP server at %s failed to accept TLS connection "
+            "because of: %s" % (IMAP_SERVER, exception))
+
+    if server_is_local and not connection_is_secure:
+        log.LOGGER.warning(
+            "IMAP server is local. "
+            "Will allow transmitting unencrypted credentials.")
+
+    if connection_is_secure or server_is_local:
+        try:
+            connection.login(user, password)
+            connection.logout()
+            log.LOGGER.debug(
+                "Authenticated IMAP user %s "
+                "via %s." % (user, IMAP_SERVER))
+            return True
+        except (imaplib.IMAP4.error, imaplib.IMAP4.abort) as exception:
+            log.LOGGER.error(
+                "IMAP server could not authenticate user %s "
+                "because of: %s" % (user, exception))
+    else:
+        log.LOGGER.critical(
+            "IMAP server did not support TLS and is not ``localhost``. "
+            "Refusing to transmit passwords under these conditions. "
+            "Authentication attempt aborted.")
+    return False  # authentication failed