Lib/configparser.py

"""Configuration file parser.

A configuration file consists of sections, lead by a "[section]" header,
and followed by "name: value" entries, with continuations and such in
the style of RFC 822.

The option values can contain format strings which refer to other values in
the same section, or values in a special [DEFAULT] section.

For example:

    something: %(dir)s/whatever

would resolve the "%(dir)s" to the value of dir.  All reference
expansions are done late, on demand.

Intrinsic defaults can be specified by passing them into the
ConfigParser constructor as a dictionary.

class:

ConfigParser -- responsible for parsing a list of
                configuration files, and managing the parsed database.

    methods:

    __init__(defaults=None, dict_type=_default_dict,
             delimiters=('=', ':'), comment_prefixes=('#', ';'),
             empty_lines_in_values=True, allow_no_value=False):
        Create the parser. When `defaults' is given, it is initialized into the
        dictionary or intrinsic defaults. The keys must be strings, the values
        must be appropriate for %()s string interpolation.  Note that `__name__'
        is always an intrinsic default; its value is the section's name.

        When `dict_type' is given, it will be used to create the dictionary
        objects for the list of sections, for the options within a section, and
        for the default values.

        When `delimiters' is given, it will be used as the set of substrings
        that divide keys from values.

        When `comment_prefixes' is given, it will be used as the set of
        substrings that prefix comments in a line.

        When `empty_lines_in_values' is False (default: True), each empty line
        marks the end of an option. Otherwise, internal empty lines of
        a multiline option are kept as part of the value.

        When `allow_no_value' is True (default: False), options without
        values are accepted; the value presented for these is None.

    sections()
        Return all the configuration section names, sans DEFAULT.

    has_section(section)
        Return whether the given section exists.

    has_option(section, option)
        Return whether the given option exists in the given section.

    options(section)
        Return list of configuration options for the named section.

    read(filenames, encoding=None)
        Read and parse the list of named configuration files, given by
        name.  A single filename is also allowed.  Non-existing files
        are ignored.  Return list of successfully read files.

    readfp(fp, filename=None)
        Read and parse one configuration file, given as a file object.
        The filename defaults to fp.name; it is only used in error
        messages (if fp has no `name' attribute, the string `<???>' is used).

    get(section, option, raw=False, vars=None)
        Return a string value for the named option.  All % interpolations are
        expanded in the return values, based on the defaults passed into the
        constructor and the DEFAULT section.  Additional substitutions may be
        provided using the `vars' argument, which must be a dictionary whose
        contents override any pre-existing defaults.

    getint(section, options)
        Like get(), but convert value to an integer.

    getfloat(section, options)
        Like get(), but convert value to a float.

    getboolean(section, options)
        Like get(), but convert value to a boolean (currently case
        insensitively defined as 0, false, no, off for False, and 1, true,
        yes, on for True).  Returns False or True.

    items(section, raw=False, vars=None)
        Return a list of tuples with (name, value) for each option
        in the section.

    remove_section(section)
        Remove the given file section and all its options.

    remove_option(section, option)
        Remove the given option from the given section.

    set(section, option, value)
        Set the given option.

    write(fp, space_around_delimiters=True)
        Write the configuration state in .ini format. If
        `space_around_delimiters' is True (the default), delimiters
        between keys and values are surrounded by spaces.
"""

try:
    from collections import OrderedDict as _default_dict
except ImportError:
    # fallback for setup.py which hasn't yet built _collections
    _default_dict = dict

import re
import sys

__all__ = ["NoSectionError", "DuplicateSectionError", "NoOptionError",
           "InterpolationError", "InterpolationDepthError",
           "InterpolationSyntaxError", "ParsingError",
           "MissingSectionHeaderError",
           "ConfigParser", "SafeConfigParser", "RawConfigParser",
           "DEFAULTSECT", "MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10



# exception classes
class Error(Exception):
    """Base class for ConfigParser exceptions."""

    def _get_message(self):
        """Getter for 'message'; needed only to override deprecation in
        BaseException.
        """
        return self.__message

    def _set_message(self, value):
        """Setter for 'message'; needed only to override deprecation in
        BaseException.
        """
        self.__message = value

    # BaseException.message has been deprecated since Python 2.6.  To prevent
    # DeprecationWarning from popping up over this pre-existing attribute, use a
    # new property that takes lookup precedence.
    message = property(_get_message, _set_message)

    def __init__(self, msg=''):
        self.message = msg
        Exception.__init__(self, msg)

    def __repr__(self):
        return self.message

    __str__ = __repr__


class NoSectionError(Error):
    """Raised when no section matches a requested option."""

    def __init__(self, section):
        Error.__init__(self, 'No section: %r' % (section,))
        self.section = section
        self.args = (section, )


class DuplicateSectionError(Error):
    """Raised when a section is multiply-created."""

    def __init__(self, section):
        Error.__init__(self, "Section %r already exists" % section)
        self.section = section
        self.args = (section, )


class NoOptionError(Error):
    """A requested option was not found."""

    def __init__(self, option, section):
        Error.__init__(self, "No option %r in section: %r" %
                       (option, section))
        self.option = option
        self.section = section
        self.args = (option, section)


class InterpolationError(Error):
    """Base class for interpolation-related exceptions."""

    def __init__(self, option, section, msg):
        Error.__init__(self, msg)
        self.option = option
        self.section = section
        self.args = (option, section, msg)


class InterpolationMissingOptionError(InterpolationError):
    """A string substitution required a setting which was not available."""

    def __init__(self, option, section, rawval, reference):
        msg = ("Bad value substitution:\n"
               "\tsection: [%s]\n"
               "\toption : %s\n"
               "\tkey    : %s\n"
               "\trawval : %s\n"
               % (section, option, reference, rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.reference = reference
        self.args = (option, section, rawval, reference)


class InterpolationSyntaxError(InterpolationError):
    """Raised when the source text into which substitutions are made
    does not conform to the required syntax."""


class InterpolationDepthError(InterpolationError):
    """Raised when substitutions are nested too deeply."""

    def __init__(self, option, section, rawval):
        msg = ("Value interpolation too deeply recursive:\n"
               "\tsection: [%s]\n"
               "\toption : %s\n"
               "\trawval : %s\n"
               % (section, option, rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.args = (option, section, rawval)


class ParsingError(Error):
    """Raised when a configuration file does not follow legal syntax."""

    def __init__(self, filename):
        Error.__init__(self, 'File contains parsing errors: %s' % filename)
        self.filename = filename
        self.errors = []
        self.args = (filename, )

    def append(self, lineno, line):
        self.errors.append((lineno, line))
        self.message += '\n\t[line %2d]: %s' % (lineno, line)


class MissingSectionHeaderError(ParsingError):
    """Raised when a key-value pair is found before any section header."""

    def __init__(self, filename, lineno, line):
        Error.__init__(
            self,
            'File contains no section headers.\nfile: %s, line: %d\n%r' %
            (filename, lineno, line))
        self.filename = filename
        self.lineno = lineno
        self.line = line
        self.args = (filename, lineno, line)


class RawConfigParser:
    """ConfigParser that does not do interpolation."""

    # Regular expressions for parsing section headers and options
    _SECT_TMPL = r"""
        \[                                 # [
        (?P<header>[^]]+)                  # very permissive!
        \]                                 # ]
        """
    _OPT_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?P<vi>{delim})\s*              # any number of space/tab,
                                           # followed by any of the
                                           # allowed delimiters,
                                           # followed by any space/tab
        (?P<value>.*)$                     # everything up to eol
        """
    _OPT_NV_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?:                             # any number of space/tab,
        (?P<vi>{delim})\s*                 # optionally followed by
                                           # any of the allowed
                                           # delimiters, followed by any
                                           # space/tab
        (?P<value>.*))?$                   # everything up to eol
        """

    # Compiled regular expression for matching sections
    SECTCRE = re.compile(_SECT_TMPL, re.VERBOSE)
    # Compiled regular expression for matching options with typical separators
    OPTCRE = re.compile(_OPT_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching options with optional values
    # delimited using typical separators
    OPTCRE_NV = re.compile(_OPT_NV_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching leading whitespace in a line
    NONSPACECRE = re.compile(r"\S")
    # Select backwards-compatible inline comment character behavior
    # (; and # are comments at the start of a line, but ; only inline)
    _COMPATIBLE = object()

    def __init__(self, defaults=None, dict_type=_default_dict,
                 delimiters=('=', ':'), comment_prefixes=_COMPATIBLE,
                 empty_lines_in_values=True, allow_no_value=False):
        self._dict = dict_type
        self._sections = self._dict()
        self._defaults = self._dict()
        if defaults:
            for key, value in defaults.items():
                self._defaults[self.optionxform(key)] = value
        self._delimiters = tuple(delimiters)
        if delimiters == ('=', ':'):
            self._optcre = self.OPTCRE_NV if allow_no_value else self.OPTCRE
        else:
            delim = "|".join(re.escape(d) for d in delimiters)
            if allow_no_value:
                self._optcre = re.compile(self._OPT_NV_TMPL.format(delim=delim),
                                          re.VERBOSE)
            else:
                self._optcre = re.compile(self._OPT_TMPL.format(delim=delim),
                                          re.VERBOSE)
        if comment_prefixes is self._COMPATIBLE:
            self._startonly_comment_prefixes = ('#',)
            self._comment_prefixes = (';',)
        else:
            self._startonly_comment_prefixes = ()
            self._comment_prefixes = tuple(comment_prefixes or ())
        self._empty_lines_in_values = empty_lines_in_values

    def defaults(self):
        return self._defaults

    def sections(self):
        """Return a list of section names, excluding [DEFAULT]"""
        # self._sections will never have [DEFAULT] in it
        return list(self._sections.keys())

    def add_section(self, section):
        """Create a new section in the configuration.

        Raise DuplicateSectionError if a section by the specified name
        already exists. Raise ValueError if name is DEFAULT or any of it's
        case-insensitive variants.
        """
        if section.lower() == "default":
            raise ValueError('Invalid section name: %s' % section)

        if section in self._sections:
            raise DuplicateSectionError(section)
        self._sections[section] = self._dict()

    def has_section(self, section):
        """Indicate whether the named section is present in the configuration.

        The DEFAULT section is not acknowledged.
        """
        return section in self._sections

    def options(self, section):
        """Return a list of option names for the given section name."""
        try:
            opts = self._sections[section].copy()
        except KeyError:
            raise NoSectionError(section)
        opts.update(self._defaults)
        if '__name__' in opts:
            del opts['__name__']
        return list(opts.keys())

    def read(self, filenames, encoding=None):
        """Read and parse a filename or a list of filenames.

        Files that cannot be opened are silently ignored; this is
        designed so that you can specify a list of potential
        configuration file locations (e.g. current directory, user's
        home directory, systemwide directory), and all existing
        configuration files in the list will be read.  A single
        filename may also be given.

        Return list of successfully read files.
        """
        if isinstance(filenames, str):
            filenames = [filenames]
        read_ok = []
        for filename in filenames:
            try:
                fp = open(filename, encoding=encoding)
            except IOError:
                continue
            self._read(fp, filename)
            fp.close()
            read_ok.append(filename)
        return read_ok

    def readfp(self, fp, filename=None):
        """Like read() but the argument must be a file-like object.

        The `fp' argument must have a `readline' method.  Optional
        second argument is the `filename', which if not given, is
        taken from fp.name.  If fp has no `name' attribute, `<???>' is
        used.
        """
        if filename is None:
            try:
                filename = fp.name
            except AttributeError:
                filename = '<???>'
        self._read(fp, filename)

    def get(self, section, option):
        opt = self.optionxform(option)
        if section not in self._sections:
            if section != DEFAULTSECT:
                raise NoSectionError(section)
            if opt in self._defaults:
                return self._defaults[opt]
            else:
                raise NoOptionError(option, section)
        elif opt in self._sections[section]:
            return self._sections[section][opt]
        elif opt in self._defaults:
            return self._defaults[opt]
        else:
            raise NoOptionError(option, section)

    def items(self, section):
        try:
            d2 = self._sections[section]
        except KeyError:
            if section != DEFAULTSECT:
                raise NoSectionError(section)
            d2 = self._dict()
        d = self._defaults.copy()
        d.update(d2)
        if "__name__" in d:
            del d["__name__"]
        return d.items()

    def _get(self, section, conv, option):
        return conv(self.get(section, option))

    def getint(self, section, option):
        return self._get(section, int, option)

    def getfloat(self, section, option):
        return self._get(section, float, option)

    _boolean_states = {'1': True, 'yes': True, 'true': True, 'on': True,
                       '0': False, 'no': False, 'false': False, 'off': False}

    def getboolean(self, section, option):
        v = self.get(section, option)
        if v.lower() not in self._boolean_states:
            raise ValueError('Not a boolean: %s' % v)
        return self._boolean_states[v.lower()]

    def optionxform(self, optionstr):
        return optionstr.lower()

    def has_option(self, section, option):
        """Check for the existence of a given option in a given section."""

        if not section or section == DEFAULTSECT:
            option = self.optionxform(option)
            return option in self._defaults
        elif section not in self._sections:
            return False
        else:
            option = self.optionxform(option)
            return (option in self._sections[section]
                    or option in self._defaults)

    def set(self, section, option, value=None):
        """Set an option."""

        if not section or section == DEFAULTSECT:
            sectdict = self._defaults
        else:
            try:
                sectdict = self._sections[section]
            except KeyError:
                raise NoSectionError(section)
        sectdict[self.optionxform(option)] = value

    def write(self, fp, space_around_delimiters=True):
        """Write an .ini-format representation of the configuration state.

        If `space_around_delimiters' is True (the default), delimiters
        between keys and values are surrounded by spaces.
        """
        if space_around_delimiters:
            d = " {} ".format(self._delimiters[0])
        else:
            d = self._delimiters[0]
        if self._defaults:
            self._write_section(fp, DEFAULTSECT, self._defaults.items(), d)
        for section in self._sections:
            self._write_section(fp, section,
                                self._sections[section].items(), d)

    def _write_section(self, fp, section_name, section_items, delimiter):
        """Write a single section to the specified `fp'."""
        fp.write("[{}]\n".format(section_name))
        for key, value in section_items:
            if key == "__name__":
                continue
            if value is not None:
                value = delimiter + str(value).replace('\n', '\n\t')
            else:
                value = ""
            fp.write("{}{}\n".format(key, value))
        fp.write("\n")

    def remove_option(self, section, option):
        """Remove an option."""
        if not section or section == DEFAULTSECT:
            sectdict = self._defaults
        else:
            try:
                sectdict = self._sections[section]
            except KeyError:
                raise NoSectionError(section)
        option = self.optionxform(option)
        existed = option in sectdict
        if existed:
            del sectdict[option]
        return existed

    def remove_section(self, section):
        """Remove a file section."""
        existed = section in self._sections
        if existed:
            del self._sections[section]
        return existed

    def _read(self, fp, fpname):
        """Parse a sectioned configuration file.

        Each section in a configuration file contains a header, indicated by a
        name in square brackets (`[]'), plus key/value options, indicated by
        `name' and `value' delimited with a specific substring (`=' or `:' by
        default).

        Values can span multiple lines, as long as they are indented deeper than
        the first line of the value. Depending on the parser's mode, blank lines
        may be treated as parts of multiline values or ignored.

        Configuration files may include comments, prefixed by specific
        characters (`#' and `;' by default). Comments may appear on their own in
        an otherwise empty line or may be entered in lines holding values or
        section names.
        """
        cursect = None                        # None, or a dictionary
        optname = None
        lineno = 0
        indent_level = 0
        e = None                              # None, or an exception
        for lineno, line in enumerate(fp, start=1):
            # strip full line comments
            comment_start = None
            for prefix in self._startonly_comment_prefixes:
                if line.strip().startswith(prefix):
                    comment_start = 0
                    break
            # strip inline comments
            for prefix in self._comment_prefixes:
                index = line.find(prefix)
                if index == 0 or (index > 0 and line[index-1].isspace()):
                    comment_start = index
                    break
            value = line[:comment_start].strip()
            if not value:
                if self._empty_lines_in_values:
                    # add empty line to the value, but only if there was no
                    # comment on the line
                    if (comment_start is None and
                        cursect is not None and
                        optname and
                        cursect[optname] is not None):
                        cursect[optname].append('') # newlines added at join
                else:
                    # empty line marks end of value
                    indent_level = sys.maxsize
                continue
            # continuation line?
            first_nonspace = self.NONSPACECRE.search(line)
            cur_indent_level = first_nonspace.start() if first_nonspace else 0
            if (cursect is not None and optname and
                cur_indent_level > indent_level):
                cursect[optname].append(value)
            # a section header or option header?
            else:
                indent_level = cur_indent_level
                # is it a section header?
                mo = self.SECTCRE.match(value)
                if mo:
                    sectname = mo.group('header')
                    if sectname in self._sections:
                        cursect = self._sections[sectname]
                    elif sectname == DEFAULTSECT:
                        cursect = self._defaults
                    else:
                        cursect = self._dict()
                        cursect['__name__'] = sectname
                        self._sections[sectname] = cursect
                    # So sections can't start with a continuation line
                    optname = None
                # no section header in the file?
                elif cursect is None:
                    raise MissingSectionHeaderError(fpname, lineno, line)
                # an option line?
                else:
                    mo = self._optcre.match(value)
                    if mo:
                        optname, vi, optval = mo.group('option', 'vi', 'value')
                        if not optname:
                            e = self._handle_error(e, fpname, lineno, line)
                        optname = self.optionxform(optname.rstrip())
                        # This check is fine because the OPTCRE cannot
                        # match if it would set optval to None
                        if optval is not None:
                            optval = optval.strip()
                            # allow empty values
                            if optval == '""':
                                optval = ''
                            cursect[optname] = [optval]
                        else:
                            # valueless option handling
                            cursect[optname] = optval
                    else:
                        # a non-fatal parsing error occurred. set up the
                        # exception but keep going. the exception will be
                        # raised at the end of the file and will contain a
                        # list of all bogus lines
                        e = self._handle_error(e, fpname, lineno, line)
        # if any parsing errors occurred, raise an exception
        if e:
            raise e
        self._join_multiline_values()

    def _join_multiline_values(self):
        all_sections = [self._defaults]
        all_sections.extend(self._sections.values())
        for options in all_sections:
            for name, val in options.items():
                if isinstance(val, list):
                    options[name] = '\n'.join(val).rstrip()

    def _handle_error(self, exc, fpname, lineno, line):
        if not exc:
            exc = ParsingError(fpname)
        exc.append(lineno, repr(line))
        return exc


class ConfigParser(RawConfigParser):
    """ConfigParser implementing interpolation."""

    def get(self, section, option, raw=False, vars=None):
        """Get an option value for a given section.

        All % interpolations are expanded in the return values, based on the
        defaults passed into the constructor, unless the optional argument
        `raw' is true.  Additional substitutions may be provided using the
        `vars' argument, which must be a dictionary whose contents overrides
        any pre-existing defaults.

        The section DEFAULT is special.
        """
        d = self._defaults.copy()
        try:
            d.update(self._sections[section])
        except KeyError:
            if section != DEFAULTSECT:
                raise NoSectionError(section)
        # Update with the entry specific variables
        if vars:
            for key, value in vars.items():
                d[self.optionxform(key)] = value
        option = self.optionxform(option)
        try:
            value = d[option]
        except KeyError:
            raise NoOptionError(option, section)

        if raw or value is None:
            return value
        else:
            return self._interpolate(section, option, value, d)

    def items(self, section, raw=False, vars=None):
        """Return a list of tuples with (name, value) for each option
        in the section.

        All % interpolations are expanded in the return values, based on the
        defaults passed into the constructor, unless the optional argument
        `raw' is true.  Additional substitutions may be provided using the
        `vars' argument, which must be a dictionary whose contents overrides
        any pre-existing defaults.

        The section DEFAULT is special.
        """
        d = self._defaults.copy()
        try:
            d.update(self._sections[section])
        except KeyError:
            if section != DEFAULTSECT:
                raise NoSectionError(section)
        # Update with the entry specific variables
        if vars:
            for key, value in vars.items():
                d[self.optionxform(key)] = value
        options = list(d.keys())
        if "__name__" in options:
            options.remove("__name__")
        if raw:
            return [(option, d[option])
                    for option in options]
        else:
            return [(option, self._interpolate(section, option, d[option], d))
                    for option in options]

    def _interpolate(self, section, option, rawval, vars):
        # do the string interpolation
        value = rawval
        depth = MAX_INTERPOLATION_DEPTH
        while depth:                    # Loop through this until it's done
            depth -= 1
            if value and "%(" in value:
                value = self._KEYCRE.sub(self._interpolation_replace, value)
                try:
                    value = value % vars
                except KeyError as e:
                    raise InterpolationMissingOptionError(
                        option, section, rawval, e.args[0])
            else:
                break
        if value and "%(" in value:
            raise InterpolationDepthError(option, section, rawval)
        return value

    _KEYCRE = re.compile(r"%\(([^)]*)\)s|.")

    def _interpolation_replace(self, match):
        s = match.group(1)
        if s is None:
            return match.group()
        else:
            return "%%(%s)s" % self.optionxform(s)


class SafeConfigParser(ConfigParser):
    """ConfigParser implementing sane interpolation."""

    def _interpolate(self, section, option, rawval, vars):
        # do the string interpolation
        L = []
        self._interpolate_some(option, L, rawval, section, vars, 1)
        return ''.join(L)

    _interpvar_re = re.compile(r"%\(([^)]+)\)s")

    def _interpolate_some(self, option, accum, rest, section, map, depth):
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rest)
        while rest:
            p = rest.find("%")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "%":
                accum.append("%")
                rest = rest[2:]
            elif c == "(":
                m = self._interpvar_re.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                var = self.optionxform(m.group(1))
                rest = rest[m.end():]
                try:
                    v = map[var]
                except KeyError:
                    raise InterpolationMissingOptionError(
                        option, section, rest, var)
                if "%" in v:
                    self._interpolate_some(option, accum, v,
                                           section, map, depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'%%' must be followed by '%%' or '(', found: %r" % (rest,))

    def set(self, section, option, value=None):
        """Set an option.  Extend ConfigParser.set: check for string values."""
        # The only legal non-string value if we allow valueless
        # options is None, so we need to check if the value is a
        # string if:
        # - we do not allow valueless options, or
        # - we allow valueless options but the value is not None
        if self._optcre is self.OPTCRE or value:
            if not isinstance(value, str):
                raise TypeError("option values must be strings")
        # check for bad percent signs:
        # first, replace all "good" interpolations
        tmp_value = value.replace('%%', '')
        tmp_value = self._interpvar_re.sub('', tmp_value)
        # then, check if there's a lone percent sign left
        percent_index = tmp_value.find('%')
        if percent_index != -1:
            raise ValueError("invalid interpolation syntax in %r at "
                             "position %d" % (value, percent_index))
        ConfigParser.set(self, section, option, value)