Beaker is a web session and general caching library that includes WSGI
 middleware for use in web applications.
 .
 As a general caching library, Beaker can handle storing for various times any
 Python object that can be pickled with optional back-ends on a fine-grained
 basis.
 .
 Features:
  * Fast, robust performance
  * Multiple reader/single writer lock system to avoid duplicate simultaneous
    cache creation
  * Cache back-ends include dbm, file, memory, memcached, and database (using
    SQLAlchemy for multiple-db vendor support)
  * Signed cookies to prevent session hijacking/spoofing
  * Cookie-only sessions to remove the need for a database or file backend
    (ideal for clustered systems)
  * Extensible Container object to support new back-ends
  * Caches can be divided into namespaces (to represent templates, objects,
    etc.) then keyed for different copies
  * Create functions for automatic call-backs to create new cache copies after
    expiration
  * Fine-grained toggling of back-ends, keys, and expiration per Cache object