Source Code for Module Pyblosxom.cache.base

  1  ####################################################################### 
  2  # This file is part of PyBlosxom. 
  3  # 
  4  # Copyright (c) 2003, 2004, 2005, 2006 Wari Wahab 
  5  #  
  6  # PyBlosxom is distributed under the MIT license.  See the file LICENSE 
  7  # for distribution details. 
  8  # 
  9  # $Id: base.py 913 2006-08-08 20:29:42Z willhelm $ 
 10  ####################################################################### 
 11  """ 
 12  The cache base class.  Subclasses of this class provide caching for 
 13  blog entry data in PyBlosxom. 
 14  """ 
 15   
 16  __revision__ = "$Revision: 913 $" 
 17   
 18 -class BlosxomCacheBase: 
 19      """ 
 20      Base Class for Caching stories in pyblosxom. 
 21   
 22      A cache is a disposable piece of data that gets updated when an entry  
 23      is in a fresh state. 
 24   
 25      Drivers are to subclass this object, overriding methods defined in  
 26      this class.  If there is an error in creating cache data, be as quite  
 27      as possible, document how a user could check whether his cache works. 
 28   
 29      Driver should expect empty caches and should attempt to create them from 
 30      scratch. 
 31   
 32      @ivar _config: String containing config on where to store the cache. 
 33          The value of config is derived from C{py['cacheConfig']} in config.py. 
 34      @type _config: string 
 35      """ 
 36 -    def __init__(self, req, config): 
 37          """ 
 38          Constructor - setup and load up the cache 
 39   
 40          @param req: the request object 
 41          @type req: Request 
 42   
 43          @param config: String containing config on where to store the cache 
 44          @type config: string 
 45          """ 
 46          self._request = req 
 47          self._config = config 
 48   
 49          self._entryid = "" 
 50          self._entrydata = {} 
 51   
 52 -    def load(self, entryid): 
 53          """ 
 54          Try to load up the cache with entryid (a unique key for the entry) 
 55   
 56          @param entryid: The key identifier for your cache 
 57          @type entryid: string 
 58          """ 
 59          self._entryid = entryid # The filename of the entry 
 60          self._entrydata = {}    # The data of the entry 
 61   
 62 -    def getEntry(self): 
 63          """ 
 64          Gets the data from the cache, returns a dict or an empty dict. 
 65          """ 
 66          return self._entrydata 
 67   
 68 -    def isCached(self): 
 69          """ 
 70          Returns 0 or 1 based on whether there is cached data, returns 0 is 
 71          cache data is stale 
 72   
 73          @returns: 0 or 1 based on cache 
 74          @rtype: boolean 
 75          """ 
 76          return 0 
 77   
 78 -    def saveEntry(self, entrydata): 
 79          """ 
 80          Store entrydata in cache 
 81   
 82          @param entrydata: The payload, usually a dict 
 83          @type entrydata: dict 
 84          """ 
 85          pass 
 86   
 87 -    def rmEntry(self): 
 88          """ 
 89          Remove cache entry: This is not used by pyblosxom, but used by 
 90          utilities. 
 91          """ 
 92          pass 
 93   
 94 -    def close(self): 
 95          """ 
 96          Override this to close your cache if necessary. 
 97          """ 
 98          pass 
 99   
100 -    def __getitem__(self, key): 
101          """ 
102          Convenience function to make this class look like a dict. 
103          """ 
104          self.load(key) 
105          if not self.has_key(key): 
106              raise KeyError 
107          return self.getEntry() 
108   
109 -    def __setitem__(self, key, value): 
110          """ 
111          Synonymous to L{saveEntry} 
112          """ 
113          self.load(key) 
114          self.saveEntry(value) 
115   
116 -    def __delitem__(self, key): 
117          """ 
118          Convenience function to make this look more like a dict. 
119          """ 
120          self.load(key) 
121          self.rmEntry() 
122   
123 -    def has_key(self, key): 
124          """ 
125          Convenience function to make this look more like a dict. 
126          """ 
127          self.load(key) 
128          return self.isCached() 
129   
130 -    def keys(self): 
131          """ 
132          List out a list of keys for the cache, to be overridden by a subclass 
133          if a full dict interface is required. 
134          """ 
135          return [] 
136   
137 -    def get(self, key, default=None): 
138          """ 
139          Convenience function to make this look more like a dict. 
140          """ 
141          try: 
142              return self.__getitem__(key) 
143          except KeyError: 
144              return default 
145   
146   
147 -class BlosxomCache(BlosxomCacheBase): 
148      """ 
149      A null cache. 
150      """ 
151      pass 
152   
153  # vim: tabstop=4 shiftwidth=4 expandtab 
154