forked from public/pyceo
163 lines
4.3 KiB
Python
163 lines
4.3 KiB
Python
"""
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Configuration Utility Module
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This module contains functions to load and verify very simple configuration
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files. Python supports ".ini" files, which suck, so this module is used
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instead.
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Example Configuration File:
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include /path/to/other.cf
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# these values are the same:
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name_protected = "Michael Spang"
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name_unprotected = Michael Spang
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# these values are not the same:
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yes_no = " yes"
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no_yes = yes
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# this value is an integer
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arbitrary_number=2
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# this value is not an integer
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arbitrary_string="2"
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# this is a key with no value
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csclub
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# this key contains whitespace
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white space = sure, why not
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# these two lines are treated as one
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long line = first line \\
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second line
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Resultant Dictionary:
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{
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'name_protected': 'Michael Spang',
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'name_unprotected:' 'Michael Spang',
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'yes_no': ' yes',
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'no_yes': 'yes',
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'arbirary_number': 2,
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'arbitrary_string': '2',
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'csclub': None,
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'white space': 'sure, why not'
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'long line': 'first line \\n second line'
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... (data from other.cf) ...
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}
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"""
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from curses.ascii import isspace
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class ConfigurationException(Exception):
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"""Exception class for incomplete and incorrect configurations."""
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def read(filename, included=None):
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"""
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Function to read a configuration file into a dictionary.
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Parmaeters:
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filename - the file to read
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included - files previously read (internal)
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Exceptions:
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IOError - when the configuration file cannot be read
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"""
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if not included:
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included = []
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if filename in included:
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return {}
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included.append(filename)
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conffile = open(filename)
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options = {}
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while True:
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line = conffile.readline()
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if line == '':
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break
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# remove comments
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if '#' in line:
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line = line[:line.find('#')]
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# combine lines when the newline is escaped with \
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while len(line) > 1 and line[-2] == '\\':
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line = line[:-2] + line[-1]
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next = conffile.readline()
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line += next
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if next == '':
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break
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line = line.strip()
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# process include statements
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if line.find("include") == 0 and isspace(line[7]):
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filename = line[8:].strip()
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options.update(read(filename, included))
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continue
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# split 'key = value' into key and value and strip results
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pair = map(str.strip, line.split('=', 1))
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# found key and value
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if len(pair) == 2:
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key, val = pair
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# found quoted string?
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if val and val[0] == val[-1] == '"':
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val = val[1:-1]
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# unquoted, found num?
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elif val:
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try:
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if "." in val:
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val = float(val)
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elif val[0] == '0':
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val = int(val, 8)
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else:
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val = int(val)
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except ValueError:
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pass
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# save key and value
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options[key] = val
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# found only key, value = None
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elif len(pair[0]) > 1:
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key = pair[0]
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options[key] = None
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return options
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def check_string_fields(filename, field_list, cfg):
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"""Function to verify thatfields are strings."""
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for field in field_list:
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if field not in cfg or type(cfg[field]) is not str:
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raise ConfigurationException('expected string value for option "%s" in "%s"' % (field, filename))
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def check_integer_fields(filename, field_list, cfg):
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"""Function to verify that fields are integers."""
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for field in field_list:
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if field not in cfg or type(cfg[field]) not in (int, long):
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raise ConfigurationException('expected numeric value for option "%s" in "%s"' % (field, filename))
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def check_float_fields(filename, field_list, cfg):
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"""Function to verify that fields are integers or floats."""
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for field in field_list:
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if field not in cfg or type(cfg[field]) not in (float, long, int):
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raise ConfigurationException('expected float value for option "%s" in "%s"' % (field, filename))
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