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deb-python-rfc3986
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deb-python-rfc3986/src/rfc3986/misc.py

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# -*- coding: utf-8 -*-
# Copyright (c) 2014 Rackspace
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Module containing compiled regular expressions and constants.
This module contains important constants, patterns, and compiled regular
expressions for parsing and validating URIs and their components.
"""
import re
# These are enumerated for the named tuple used as a superclass of
# URIReference
URI_COMPONENTS = ['scheme', 'authority', 'path', 'query', 'fragment']
important_characters = {
'generic_delimiters': ":/?#[]@",
'sub_delimiters': "!$&'()*+,;=",
# We need to escape the '*' in this case
're_sub_delimiters': "!$&'()\*+,;=",
'unreserved_chars': ('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
'0123456789._~-'),
# We need to escape the '-' in this case:
're_unreserved': 'A-Za-z0-9._~\-',
}
# For details about delimiters and reserved characters, see:
# http://tools.ietf.org/html/rfc3986#section-2.2
GENERIC_DELIMITERS = set(important_characters['generic_delimiters'])
SUB_DELIMITERS = set(important_characters['sub_delimiters'])
RESERVED_CHARS = GENERIC_DELIMITERS.union(SUB_DELIMITERS)
# For details about unreserved characters, see:
# http://tools.ietf.org/html/rfc3986#section-2.3
UNRESERVED_CHARS = set(important_characters['unreserved_chars'])
NON_PCT_ENCODED = RESERVED_CHARS.union(UNRESERVED_CHARS).union('%')
# Extracted from http://tools.ietf.org/html/rfc3986#appendix-B
component_pattern_dict = {
# NOTE(sigmavirus24): Our list of things we want to not match includes one
# item more than the RFC. We want to not parse the leading '[' from an
# IPv6 address into the scheme when provided something akin to:
# >>> rfc3986.uri_reference('[::1]')
# We would rather that appear to be a path than not.
'scheme': '[^:/?#[]+',
'authority': '[^/?#]*',
'path': '[^?#]*',
'query': '[^#]*',
'fragment': '.*',
}
# See http://tools.ietf.org/html/rfc3986#appendix-B
# In this case, we name each of the important matches so we can use
# SRE_Match#groupdict to parse the values out if we so choose. This is also
# modified to ignore other matches that are not important to the parsing of
# the reference so we can also simply use SRE_Match#groups.
expression = ('(?:(?P<scheme>{scheme}):)?(?://(?P<authority>{authority}))?'
'(?P<path>{path})(?:\?(?P<query>{query}))?'
'(?:#(?P<fragment>{fragment}))?'
).format(**component_pattern_dict)
URI_MATCHER = re.compile(expression)
# #########################
# Authority Matcher Section
# #########################
# Host patterns, see: http://tools.ietf.org/html/rfc3986#section-3.2.2
# The pattern for a regular name, e.g., www.google.com, api.github.com
reg_name = '(({0})*|[{1}]*)'.format(
'%[0-9A-Fa-f]{2}',
important_characters['re_sub_delimiters'] +
important_characters['re_unreserved']
)
# The pattern for an IPv4 address, e.g., 192.168.255.255, 127.0.0.1,
ipv4 = '([0-9]{1,3}.){3}[0-9]{1,3}'
# Hexadecimal characters used in each piece of an IPv6 address
hexdig = '[0-9A-Fa-f]{1,4}'
# Least-significant 32 bits of an IPv6 address
ls32 = '({hex}:{hex}|{ipv4})'.format(hex=hexdig, ipv4=ipv4)
# Substitutions into the following patterns for IPv6 patterns defined
# http://tools.ietf.org/html/rfc3986#page-20
subs = {'hex': hexdig, 'ls32': ls32}
# Below: h16 = hexdig, see: https://tools.ietf.org/html/rfc5234 for details
# about ABNF (Augmented Backus-Naur Form) use in the comments
variations = [
# 6( h16 ":" ) ls32
'(%(hex)s:){6}%(ls32)s' % subs,
# "::" 5( h16 ":" ) ls32
'::(%(hex)s:){5}%(ls32)s' % subs,
# [ h16 ] "::" 4( h16 ":" ) ls32
'(%(hex)s)?::(%(hex)s:){4}%(ls32)s' % subs,
# [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
'((%(hex)s:)?%(hex)s)?::(%(hex)s:){3}%(ls32)s' % subs,
# [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
'((%(hex)s:){0,2}%(hex)s)?::(%(hex)s:){2}%(ls32)s' % subs,
# [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32
'((%(hex)s:){0,3}%(hex)s)?::%(hex)s:%(ls32)s' % subs,
# [ *4( h16 ":" ) h16 ] "::" ls32
'((%(hex)s:){0,4}%(hex)s)?::%(ls32)s' % subs,
# [ *5( h16 ":" ) h16 ] "::" h16
'((%(hex)s:){0,5}%(hex)s)?::%(hex)s' % subs,
# [ *6( h16 ":" ) h16 ] "::"
'((%(hex)s:){0,6}%(hex)s)?::' % subs,
]
ipv6 = '(({0})|({1})|({2})|({3})|({4})|({5})|({6})|({7}))'.format(*variations)
ipv_future = 'v[0-9A-Fa-f]+.[%s]+' % (
important_characters['re_unreserved'] +
important_characters['re_sub_delimiters'] +
':')
ip_literal = '\[({0}|{1})\]'.format(ipv6, ipv_future)
# Pattern for matching the host piece of the authority
HOST_PATTERN = '({0}|{1}|{2})'.format(reg_name, ipv4, ip_literal)
SUBAUTHORITY_MATCHER = re.compile((
'^(?:(?P<userinfo>[A-Za-z0-9_.~\-%:]+)@)?' # userinfo
'(?P<host>{0}?)' # host
':?(?P<port>[0-9]+)?$' # port
).format(HOST_PATTERN))
IPv4_MATCHER = re.compile('^' + ipv4 + '$')
# ####################
# Path Matcher Section
# ####################
# See http://tools.ietf.org/html/rfc3986#section-3.3 for more information
# about the path patterns defined below.
# Percent encoded character values
pct_encoded = '%[A-Fa-f0-9]{2}'
pchar = ('([' + important_characters['re_unreserved']
+ important_characters['re_sub_delimiters']
+ ':@]|%s)' % pct_encoded)
segments = {
'segment': pchar + '*',
# Non-zero length segment
'segment-nz': pchar + '+',
# Non-zero length segment without ":"
'segment-nz-nc': pchar.replace(':', '') + '+'
}
# Path types taken from Section 3.3 (linked above)
path_empty = '^$'
path_rootless = '%(segment-nz)s(/%(segment)s)*' % segments
path_noscheme = '%(segment-nz-nc)s(/%(segment)s)*' % segments
path_absolute = '/(%s)?' % path_rootless
path_abempty = '(/%(segment)s)*' % segments
# Matcher used to validate path components
PATH_MATCHER = re.compile('^(%s|%s|%s|%s|%s)$' % (
path_abempty, path_absolute, path_noscheme, path_rootless, path_empty
))
# ##################################
# Query and Fragment Matcher Section
# ##################################
QUERY_MATCHER = re.compile(
'^([/?:@' + important_characters['re_unreserved']
+ important_characters['re_sub_delimiters']
+ ']|%s)*$' % pct_encoded)
FRAGMENT_MATCHER = QUERY_MATCHER
# Scheme validation, see: http://tools.ietf.org/html/rfc3986#section-3.1
SCHEME_MATCHER = re.compile('^[A-Za-z][A-Za-z0-9+.\-]*$')
# Relative reference matcher
# See http://tools.ietf.org/html/rfc3986#section-4.2 for details
relative_part = '(//%s%s|%s|%s|%s)' % (
component_pattern_dict['authority'], path_abempty, path_absolute,
path_noscheme, path_empty
)
RELATIVE_REF_MATCHER = re.compile('^%s(\?%s)?(#%s)?$' % (
relative_part, QUERY_MATCHER.pattern, FRAGMENT_MATCHER.pattern
))
# See http://tools.ietf.org/html/rfc3986#section-3 for definition
hier_part = '(//%s%s|%s|%s|%s)' % (
component_pattern_dict['authority'], path_abempty, path_absolute,
path_rootless, path_empty
)
# See http://tools.ietf.org/html/rfc3986#section-4.3
ABSOLUTE_URI_MATCHER = re.compile('^%s:%s(\?%s)?$' % (
component_pattern_dict['scheme'], hier_part, QUERY_MATCHER.pattern[1:-1]
))
# Path merger as defined in http://tools.ietf.org/html/rfc3986#section-5.2.3
def merge_paths(base_uri, relative_path):
"""Merge a base URI's path with a relative URI's path."""
if base_uri.path is None and base_uri.authority is not None:
return '/' + relative_path
else:
path = base_uri.path or ''
index = path.rfind('/')
return path[:index] + '/' + relative_path
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