core/confparse.py

   1 # synarere -- a highly modular and stable IRC bot.
   2 # Copyright (C) 2010 Michael Rodriguez.
   3 # Rights to this code are documented in docs/LICENSE.
   4
   5 '''Configuration parser.'''
   6
   7 # Import required Python module.
   8 import os
   9
  10 # Import required source modules.
  11 import logger, irc, var
  12
  13 class Exception(Exception):
  14     pass
  15
  16 class ConfigBlock(object):
  17     def __init__ (self, label, values={}):
  18         self.label = label
  19         self.vars = {}
  20
  21         # Copy over any values given during initialization
  22         for key in values:
  23             self.vars[key] = values[key]
  24
  25     def add (self, name, value):
  26         self.vars[name] = value
  27
  28     def get (self, name, defval=None):
  29         return self.vars.get(name, defval)
  30
  31 class ConfigParser:
  32     def __init__(self, file):
  33         self.file = file
  34         self.parse()
  35
  36     def rehash(self, on_sighup):
  37         '''Rehash configuration and change synarere to fit the new conditions.'''
  38
  39         logger.info('Rehashing configuration %s' % ('due to SIGHUP.' if on_sighup else ''))
  40         self.parse()
  41
  42     def parse(self):
  43         '''Parse our file, and put the data into a dictionary.'''
  44
  45         lno = 0
  46
  47         # Attempt to open the file.
  48         try:
  49             fh = open(self.file, 'r')
  50         except IOError, e:
  51             raise Exception(os.strerror(e.args[0]))
  52
  53         # Parse.
  54         self.blocks = []
  55
  56         for line in fh.xreadlines():
  57             for cno, c in enumerate(line):
  58                 if c == '\n':
  59                     # Increment the line number.
  60                     lno += 1
  61
  62                 if c == '#': # Comment until EOL.
  63                     break
  64                 if c == ':': # Block label.
  65                     label = line[: cno].strip()
  66                     self.blocks.append(ConfigBlock(label))
  67                 if c == '=': # Variable.
  68                     if not self.blocks:  # Skip this line, as no block label was given yet.
  69                         break
  70                     varname = line[:cno].strip()
  71                     varval = line[cno + 1:].strip()
  72                     self.blocks[-1].add(varname, varval)
  73                     break
  74
  75         # Close the file handle
  76         fh.close()
  77
  78     def xget(self, block, variable=None):
  79         '''
  80         Return whatever is in block:variable. If variable is None,
  81         we will iterate over mutiple blocks, thus allowing us to
  82         return multiple values from multiple blocks.
  83         '''
  84
  85         if block not in set(b.label for b in self.blocks):
  86             raise Exception('Block %s not found.' % block)
  87
  88         for i in self.blocks:
  89             if i.label == block:
  90                 if variable is None: # Just get blocks by this name
  91                     yield i
  92                 else: # Get a member of blocks by this name.
  93                     yield i.get(variable)
  94
  95     def get(self, block, variable=None):
  96         '''
  97         Call our iterating generator (xget) and just store all its
  98         results into a list to return all at once.
  99         '''
 100
 101         return [b for b in self.xget(block, variable)]