initial commit

cassandra_sessions/__init__.py

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+import lazyboy
+import time
+import logging
+from lazyboy.key import Key
+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.encoding import force_unicode
+from django.contrib.sessions.backends.base import SessionBase, CreateError
+
+CASSANDRA_POOL = getattr(settings, 'CASSANDRA_POOL', None)
+CASSANDRA_SESSION_KEYSPACE = getattr(settings, 'CASSANDRA_SESSION_KEYSPACE', None)
+
+if CASSANDRA_POOL is None or CASSANDRA_SESSION_KEYSPACE is None:
+    raise ImproperlyConfigured(u'To use cassandra-sessions, you must first set the CASSANDRA_SESSION_KEYSPACE and CASSANDRA_POOL settings in your settings.py')
+else:
+    try:
+        lazyboy.connection.get_pool(CASSANDRA_SESSION_KEYSPACE)
+    except lazyboy.exceptions.ErrorCassandraClientNotFound:
+        lazyboy.connection.add_pool(CASSANDRA_SESSION_KEYSPACE, CASSANDRA_POOL)
+
+class SessionStore(SessionBase):
+    """
+    A Cassandra-based session store.
+    """
+    
+    def get_session(self, session_key):
+        logging.debug('Getting session: %s' % session_key)
+        session = None
+        if session_key:
+            try:
+                key = Key(
+                    keyspace=CASSANDRA_SESSION_KEYSPACE,
+                    column_family="Sessions",
+                    key=session_key
+                )
+                record = lazyboy.record.Record()
+                session_record = record.load(key)
+                session_values = session_record.values()
+                if session_values:
+                    session = session_values[0]
+            except lazyboy.exceptions.ErrorNoSuchRecord:
+                pass
+        return session
+        
+    def load(self):
+        session_data = self.get_session(self.session_key)
+        if session_data is not None:
+            expiry, data = int(session_data[:15]), session_data[15:]
+            if expiry < time.time():
+                return {}
+            else:
+                return self.decode(force_unicode(data))
+        self.create()
+        return {}
+    
+    def create(self):
+        while True:
+            self.session_key = self._get_new_session_key()
+            try:
+                self.save()
+            except CreateError:
+                continue
+            self.modified = True
+            return
+    
+    def save(self, must_create=True):
+        data = self.encode(self._get_session(no_load=True))
+        encoded = '%15d%s' % (int(time.time()) + self.get_expiry_age(), data)
+        key = Key(
+            keyspace=CASSANDRA_SESSION_KEYSPACE,
+            column_family="Sessions",
+            key=self.session_key
+        )
+        record = lazyboy.record.Record()
+        record.key = key
+        record[self.session_key] = encoded
+        record.save()
+        
+    def exists(self, session_key):
+        session_data = self.get_session(session_key)
+        if session_data is not None:
+            expiry, data = int(session_data[:15]), session_data[15:]
+            if expiry < time.time():
+                return False
+            else:
+                return True
+        return False
+        
+    def delete(self, session_key=None):
+        if session_key is None:
+            if self._session_key is None:
+                return
+            session_key = self._session_key
+        key = Key(
+            keyspace=CASSANDRA_SESSION_KEYSPACE,
+            column_family="Sessions",
+            key=session_key
+        )
+        # make this session expire right now
+        data = self.encode({})
+        encoded = '%15d%s' % (int(time.time()), data)
+        record = lazyboy.record.Record()
+        record.key = key
+        record[self.session_key] = encoded
+        record.save()

cassandra_sessions/settings.py

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+import lazyboy
+import logging
+
+logging.basicConfig(
+    level = logging.DEBUG,
+    format = '[%(asctime)s] %(levelname)s: "%(message)s"',
+    datefmt = '%d/%b/%Y %I:%M:%S'
+)
+
+CASSANDRA_POOL = ('127.0.0.1:9160',)
+CASSANDRA_SESSION_KEYSPACE = 'Testing'
+
+lazyboy.connection.add_pool(CASSANDRA_SESSION_KEYSPACE, CASSANDRA_POOL)

cassandra_sessions/test.py

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+"""
+>>> from django.conf import settings
+>>> from cassandra_sessions import SessionStore as CassandraSession
+>>> cassandra_session = CassandraSession()
+>>> cassandra_session.modified
+False
+>>> cassandra_session.get('cat')
+>>> cassandra_session['cat'] = "dog"
+>>> cassandra_session.modified
+True
+>>> cassandra_session.pop('cat')
+'dog'
+>>> cassandra_session.pop('some key', 'does not exist')
+'does not exist'
+>>> cassandra_session.save()
+>>> cassandra_session.exists(cassandra_session.session_key)
+True
+>>> cassandra_session.delete(cassandra_session.session_key)
+>>> cassandra_session['foo'] = 'bar'
+>>> cassandra_session.save()
+>>> cassandra_session.exists(cassandra_session.session_key)
+True
+>>> prev_key = cassandra_session.session_key
+>>> cassandra_session.flush()
+>>> cassandra_session.exists(prev_key)
+False
+>>> cassandra_session.session_key == prev_key
+False
+>>> cassandra_session.modified, cassandra_session.accessed
+(True, True)
+>>> cassandra_session['a'], cassandra_session['b'] = 'c', 'd'
+>>> cassandra_session.save()
+>>> prev_key = cassandra_session.session_key
+>>> prev_data = cassandra_session.items()
+>>> cassandra_session.cycle_key()
+>>> cassandra_session.session_key == prev_key
+False
+>>> cassandra_session.items() == prev_data
+True
+"""
+
+if __name__ == '__main__':
+    import os
+    os.environ['DJANGO_SETTINGS_MODULE'] = 'settings'
+    import doctest
+    doctest.testmod()