Source Code for Module Pyblosxom.plugin_utils

  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: plugin_utils.py 1012 2007-05-19 17:57:07Z willhelm $ 
 10  ####################################################################### 
 11  """ 
 12  Holds a series of utility functions for cataloguing, retrieving, and 
 13  manipulating callback functions and chains.  Refer to the documentation 
 14  for which callbacks are available and their behavior. 
 15  """ 
 16   
 17  __revision__ = "$Revision: 1012 $" 
 18   
 19  import os 
 20  import glob 
 21  import sys 
 22  import os.path 
 23   
 24  # this holds the list of plugins that have been loaded.  if you're running 
 25  # PyBlosxom as a long-running process, this only gets cleared when the 
 26  # process is restarted. 
 27  plugins = [] 
 28   
 29  # this holds a list of callbacks (any function that begins with cp_) and the 
 30  # list of function instances that support that callback. 
 31  # if you're running PyBlosxom as a long-running process, this only 
 32  # gets cleared when the process is restarted. 
 33  callbacks = {} 
 34   
 35 -def catalogue_plugin(plugin_module): 
 36      """ 
 37      Goes through the plugin's contents and catalogues all the functions 
 38      that start with cb_.  Functions that start with cb_ are callbacks. 
 39   
 40      @param plugin_module: the module to catalogue 
 41      @type  plugin_module: module 
 42      """ 
 43      listing = dir(plugin_module) 
 44   
 45      listing = [item for item in listing if item.startswith("cb_")] 
 46   
 47      for mem in listing: 
 48          func = getattr(plugin_module, mem) 
 49          memadj = mem[3:] 
 50          if callable(func): 
 51              callbacks.setdefault(memadj, []).append(func) 
 52               
 53 -def get_callback_chain(chain): 
 54      """ 
 55      Returns a list of functions registered with the callback. 
 56   
 57      @returns: list of functions registered with the callback (or an 
 58          empty list) 
 59      @rtype: list of functions 
 60      """ 
 61      return callbacks.get(chain, []) 
 62   
 63 -def initialize_plugins(plugin_dirs, plugin_list): 
 64      """ 
 65      Imports and initializes plugins from the directories in the list 
 66      specified by "plugins_dir".  If no such list exists, then we don't 
 67      load any plugins. 
 68   
 69      If the user specifies a "load_plugins" list of plugins to load, then 
 70      we explicitly load those plugins in the order they're listed.  If the 
 71      load_plugins key does not exist, then we load all the plugins in the 
 72      plugins directory using an alphanumeric sorting order. 
 73   
 74      NOTE: If PyBlosxom is part of a long-running process, you must 
 75      restart PyBlosxom in order to pick up any changes to your plugins. 
 76   
 77      @param plugin_dirs: the list of directories to add to the sys.path 
 78          because that's where our plugins are located. 
 79      @type  plugin_dirs: list of strings 
 80   
 81      @param plugin_list: the list of plugins to load, or if None, we'll 
 82          load all the plugins we find in those dirs. 
 83      @type  plugin_list: list of strings or None 
 84      """ 
 85      if plugins: 
 86          return 
 87   
 88      # we clear out the callbacks dict so we can rebuild them 
 89      callbacks.clear() 
 90   
 91      # handle plugin_dirs here 
 92      for mem in plugin_dirs: 
 93          if os.path.isdir(mem): 
 94              sys.path.append(mem) 
 95          else: 
 96              raise Exception("Plugin directory '%s' does not exist.  " \ 
 97                              "Please check your config file." % mem) 
 98   
 99      plugin_list = get_plugin_list(plugin_list, plugin_dirs) 
100   
101      for mem in plugin_list: 
102          _module = __import__(mem) 
103          for comp in mem.split(".")[1:]: 
104              _module = getattr(_module, comp) 
105          catalogue_plugin(_module) 
106          plugins.append(_module) 
107   
108 -def get_plugin_by_name(name): 
109      """ 
110      This retrieves a plugin instance (it's a Python module instance) 
111      by name. 
112   
113      @param name: the name of the plugin to retrieve (ex: "xmlrpc") 
114      @type  name: string 
115   
116      @returns: the Python module instance for the plugin or None 
117      @rtype: Python module 
118      """ 
119      if plugins: 
120          for mem in plugins: 
121              if mem.__name__ == name: 
122                  return mem 
123      return None 
124   
125 -def get_module_name(filename): 
126      """ 
127      Takes a filename and returns the module name from the filename. 
128   
129      Example: passing in "/blah/blah/blah/module.ext" returns "module" 
130   
131      @param filename: the filename in question (with a full path) 
132      @type  filename: string 
133   
134      @returns: the filename without path or extension 
135      @rtype:   string 
136      """ 
137      return os.path.splitext(os.path.split(filename)[1])[0] 
138   
139 -def get_plugin_list(plugin_list, plugin_dirs):     
140      """ 
141      This handles the situation where the user has provided a series of 
142      plugin dirs, but has not specified which plugins they want to load 
143      from those dirs.  In this case, we load all possible plugins except 
144      the ones whose names being with _ .   
145   
146      @param plugin_list: List of plugins to load 
147      @type plugin_list: list or None 
148   
149      @param plugin_dirs: A list of directories where plugins can be loaded from 
150      @type plugin_dirs: list 
151   
152      @return: list of python module names of the plugins to load 
153      @rtype: list of strings 
154      """ 
155      if plugin_list == None: 
156          plugin_list = [] 
157          for mem in plugin_dirs: 
158              file_list = glob.glob(os.path.join(mem, "*.py")) 
159   
160              file_list = [get_module_name(filename) for filename in file_list] 
161   
162              # remove plugins that start with a _ 
163              file_list = [plugin for plugin in file_list \ 
164                           if not plugin.startswith('_')] 
165              plugin_list += file_list 
166   
167          plugin_list.sort() 
168   
169      return plugin_list 
170   
171  # vim: shiftwidth=4 tabstop=4 expandtab 
172