youtube-channel-manager/YtManagerApp/utils/extended_interpolation_with_env.py

93 lines
3.7 KiB
Python

import os
import os.path
import re
from configparser import Interpolation, NoSectionError, NoOptionError, InterpolationMissingOptionError, \
InterpolationDepthError, InterpolationSyntaxError
MAX_INTERPOLATION_DEPTH = 10
class ExtendedInterpolatorWithEnv(Interpolation):
"""Advanced variant of interpolation, supports the syntax used by
`zc.buildout'. Enables interpolation between sections.
This modified version also allows specifying environment variables
using ${env:...}, and allows adding additional options using 'set_additional_options'. """
_KEYCRE = re.compile(r"\$\{([^}]+)\}")
def before_get(self, parser, section, option, value, defaults):
L = []
self._interpolate_some(parser, option, L, value, section, defaults, 1)
return ''.join(L)
def before_set(self, parser, section, option, value):
tmp_value = value.replace('$$', '') # escaped dollar signs
tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
if '$' in tmp_value:
raise ValueError("invalid interpolation syntax in %r at "
"position %d" % (value, tmp_value.find('$')))
return value
def _resolve_option(self, option, defaults):
return defaults[option]
def _resolve_section_option(self, section, option, parser):
if section == 'env':
return os.getenv(option, '')
return parser.get(section, option, raw=True)
def _interpolate_some(self, parser, option, accum, rest, section, map,
depth):
rawval = parser.get(section, option, raw=True, fallback=rest)
if depth > MAX_INTERPOLATION_DEPTH:
raise InterpolationDepthError(option, section, rawval)
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("$")
rest = rest[2:]
elif c == "{":
m = self._KEYCRE.match(rest)
if m is None:
raise InterpolationSyntaxError(option, section,
"bad interpolation variable reference %r" % rest)
path = m.group(1).split(':')
rest = rest[m.end():]
sect = section
opt = option
try:
if len(path) == 1:
opt = parser.optionxform(path[0])
v = self._resolve_option(opt, map)
elif len(path) == 2:
sect = path[0]
opt = parser.optionxform(path[1])
v = self._resolve_section_option(sect, opt, parser)
else:
raise InterpolationSyntaxError(
option, section,
"More than one ':' found: %r" % (rest,))
except (KeyError, NoSectionError, NoOptionError):
raise InterpolationMissingOptionError(
option, section, rawval, ":".join(path)) from None
if "$" in v:
self._interpolate_some(parser, opt, accum, v, sect,
dict(parser.items(sect, raw=True)),
depth + 1)
else:
accum.append(v)
else:
raise InterpolationSyntaxError(
option, section,
"'$' must be followed by '$' or '{', "
"found: %r" % (rest,))