code.delx.au - pymsnt/blob - src/xdb.py

   1 # Copyright 2004-2005 James Bunton <james@delx.cjb.net>
   2 # Licensed for distribution under the GPL version 2, check COPYING for details
   3
   4 from tlib import xmlw
   5 from debug import LogEvent, INFO, WARN
   6 import os
   7 import os.path
   8 import shutil
   9 import md5
  10 import config
  11
  12 X = os.path.sep
  13 SPOOL_UMASK = 0077
  14
  15
  16 def unmangle(file):
  17         chunks = file.split("%")
  18         end = chunks.pop()
  19         file = "%s@%s" % ("%".join(chunks), end)
  20         return file
  21
  22 def mangle(file):
  23         return file.replace("@", "%")
  24
  25 def makeHash(file):
  26         return md5.md5(file).hexdigest()[0:3]
  27
  28
  29 class XDB:
  30         """
  31         Class for storage of data.
  32
  33         Create one instance of the class for each XDB 'folder' you want.
  34         Call request()/set() with the xdbns argument you wish to retrieve
  35         """
  36         def __init__(self, name, mangle=False):
  37                 """ Creates an XDB object. If mangle is True then any '@' signs in filenames will be changed to '%' """
  38                 self.name = os.path.join(os.path.abspath(config.spooldir), name)
  39                 if not os.path.exists(self.name):
  40                         os.makedirs(self.name)
  41                 self.mangle = mangle
  42
  43         def __getFile(self, file):
  44                 if(self.mangle):
  45                         file = mangle(file)
  46
  47                 hash = makeHash(file)
  48                 document = xmlw.parseFile(self.name + X + hash + X + file + ".xml")
  49
  50                 return document
  51
  52         def __writeFile(self, file, text):
  53                 if(self.mangle):
  54                         file = mangle(file)
  55
  56                 prev_umask = os.umask(SPOOL_UMASK)
  57                 hash = makeHash(file)
  58                 pre = self.name + X + hash + X
  59                 if not os.path.exists(pre):
  60                         os.makedirs(pre)
  61                 try:
  62                         f = open(pre + file + ".xml.new", "w")
  63                         f.write(text)
  64                         f.close()
  65                         shutil.move(pre + file + ".xml.new", pre + file + ".xml")
  66                 except IOError, e:
  67                         LogEvent(WARN, "", "IOError " + str(e))
  68                         raise
  69                 os.umask(prev_umask)
  70
  71         def files(self):
  72                 """ Returns a list containing the files in the current XDB database """
  73                 files = []
  74                 for dir in os.listdir(self.name):
  75                         if(os.path.isdir(self.name + X + dir)):
  76                                 files.extend(os.listdir(self.name + X + dir))
  77                 if self.mangle:
  78                         files = [unmangle(x)[:-4] for x in files]
  79                 else:
  80                         files = [x[:-4] for x in files]
  81
  82                 while files.count(''):
  83                         files.remove('')
  84
  85                 return files
  86
  87         def request(self, file, xdbns):
  88                 """ Requests a specific xdb namespace from the XDB 'file' """
  89                 try:
  90                         document = self.__getFile(file)
  91                         for child in document.elements():
  92                                 if(child.getAttribute("xdbns") == xdbns):
  93                                         return child
  94                 except:
  95                         return None
  96
  97         def set(self, file, xdbns, element):
  98                 """ Sets a specific xdb namespace in the XDB 'file' to element """
  99                 try:
 100                         element.attributes["xdbns"] = xdbns
 101                         document = None
 102                         try:
 103                                 document = self.__getFile(file)
 104                         except IOError:
 105                                 pass
 106                         if(not document):
 107                                 document = xmlw.Element((None, "xdb"))
 108
 109                         # Remove the existing node (if any)
 110                         for child in document.elements():
 111                                 if(child.getAttribute("xdbns") == xdbns):
 112                                         document.children.remove(child)
 113                         # Add the new one
 114                         document.addChild(element)
 115
 116                         self.__writeFile(file, document.toXml())
 117                 except IOError, e:
 118                         LogEvent(WARN, "", "IOError " + str(e))
 119                         raise
 120
 121         def remove(self, file):
 122                 """ Removes an XDB file """
 123                 file = self.name + X + file[0:2] + X + file + ".xml"
 124                 if(self.mangle):
 125                         file = mangle(file)
 126                 try:
 127                         os.remove(file)
 128                 except IOError, e:
 129                         LogEvent(WARN, "", "IOError " + str(e))
 130                         raise
 131
 132
 133