548 lines
16 KiB
Python
548 lines
16 KiB
Python
# -*- coding: utf-8 -*-
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"""
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requests.utils
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~~~~~~~~~~~~~~
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This module provides utility functions that are used within Requests
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that are also useful for external consumption.
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"""
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import cgi
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import codecs
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import collections
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import os
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import platform
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import re
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import sys
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from netrc import netrc, NetrcParseError
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from . import __version__
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from . import certs
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from .compat import parse_http_list as _parse_list_header
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from .compat import quote, urlparse, bytes, str, OrderedDict, urlunparse
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from .compat import getproxies, proxy_bypass
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from .cookies import RequestsCookieJar, cookiejar_from_dict
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from .structures import CaseInsensitiveDict
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_hush_pyflakes = (RequestsCookieJar,)
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NETRC_FILES = ('.netrc', '_netrc')
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DEFAULT_CA_BUNDLE_PATH = certs.where()
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def dict_to_sequence(d):
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"""Returns an internal sequence dictionary update."""
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if hasattr(d, 'items'):
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d = d.items()
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return d
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def super_len(o):
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if hasattr(o, '__len__'):
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return len(o)
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if hasattr(o, 'len'):
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return o.len
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if hasattr(o, 'fileno'):
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return os.fstat(o.fileno()).st_size
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def get_netrc_auth(url):
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"""Returns the Requests tuple auth for a given url from netrc."""
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try:
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locations = (os.path.expanduser('~/{0}'.format(f)) for f in NETRC_FILES)
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netrc_path = None
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for loc in locations:
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if os.path.exists(loc) and not netrc_path:
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netrc_path = loc
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# Abort early if there isn't one.
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if netrc_path is None:
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return netrc_path
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ri = urlparse(url)
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# Strip port numbers from netloc
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host = ri.netloc.split(':')[0]
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try:
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_netrc = netrc(netrc_path).authenticators(host)
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if _netrc:
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# Return with login / password
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login_i = (0 if _netrc[0] else 1)
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return (_netrc[login_i], _netrc[2])
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except (NetrcParseError, IOError):
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# If there was a parsing error or a permissions issue reading the file,
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# we'll just skip netrc auth
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pass
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# AppEngine hackiness.
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except (ImportError, AttributeError):
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pass
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def guess_filename(obj):
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"""Tries to guess the filename of the given object."""
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name = getattr(obj, 'name', None)
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if name and name[0] != '<' and name[-1] != '>':
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return os.path.basename(name)
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def from_key_val_list(value):
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"""Take an object and test to see if it can be represented as a
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dictionary. Unless it can not be represented as such, return an
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OrderedDict, e.g.,
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::
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>>> from_key_val_list([('key', 'val')])
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OrderedDict([('key', 'val')])
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>>> from_key_val_list('string')
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ValueError: need more than 1 value to unpack
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>>> from_key_val_list({'key': 'val'})
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OrderedDict([('key', 'val')])
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"""
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if value is None:
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return None
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if isinstance(value, (str, bytes, bool, int)):
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raise ValueError('cannot encode objects that are not 2-tuples')
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return OrderedDict(value)
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def to_key_val_list(value):
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"""Take an object and test to see if it can be represented as a
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dictionary. If it can be, return a list of tuples, e.g.,
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::
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>>> to_key_val_list([('key', 'val')])
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[('key', 'val')]
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>>> to_key_val_list({'key': 'val'})
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[('key', 'val')]
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>>> to_key_val_list('string')
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ValueError: cannot encode objects that are not 2-tuples.
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"""
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if value is None:
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return None
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if isinstance(value, (str, bytes, bool, int)):
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raise ValueError('cannot encode objects that are not 2-tuples')
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if isinstance(value, collections.Mapping):
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value = value.items()
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return list(value)
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# From mitsuhiko/werkzeug (used with permission).
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def parse_list_header(value):
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"""Parse lists as described by RFC 2068 Section 2.
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In particular, parse comma-separated lists where the elements of
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the list may include quoted-strings. A quoted-string could
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contain a comma. A non-quoted string could have quotes in the
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middle. Quotes are removed automatically after parsing.
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It basically works like :func:`parse_set_header` just that items
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may appear multiple times and case sensitivity is preserved.
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The return value is a standard :class:`list`:
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>>> parse_list_header('token, "quoted value"')
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['token', 'quoted value']
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To create a header from the :class:`list` again, use the
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:func:`dump_header` function.
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:param value: a string with a list header.
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:return: :class:`list`
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"""
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result = []
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for item in _parse_list_header(value):
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if item[:1] == item[-1:] == '"':
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item = unquote_header_value(item[1:-1])
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result.append(item)
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return result
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# From mitsuhiko/werkzeug (used with permission).
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def parse_dict_header(value):
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"""Parse lists of key, value pairs as described by RFC 2068 Section 2 and
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convert them into a python dict:
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>>> d = parse_dict_header('foo="is a fish", bar="as well"')
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>>> type(d) is dict
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True
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>>> sorted(d.items())
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[('bar', 'as well'), ('foo', 'is a fish')]
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If there is no value for a key it will be `None`:
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>>> parse_dict_header('key_without_value')
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{'key_without_value': None}
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To create a header from the :class:`dict` again, use the
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:func:`dump_header` function.
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:param value: a string with a dict header.
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:return: :class:`dict`
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"""
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result = {}
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for item in _parse_list_header(value):
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if '=' not in item:
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result[item] = None
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continue
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name, value = item.split('=', 1)
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if value[:1] == value[-1:] == '"':
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value = unquote_header_value(value[1:-1])
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result[name] = value
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return result
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# From mitsuhiko/werkzeug (used with permission).
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def unquote_header_value(value, is_filename=False):
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r"""Unquotes a header value. (Reversal of :func:`quote_header_value`).
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This does not use the real unquoting but what browsers are actually
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using for quoting.
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:param value: the header value to unquote.
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"""
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if value and value[0] == value[-1] == '"':
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# this is not the real unquoting, but fixing this so that the
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# RFC is met will result in bugs with internet explorer and
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# probably some other browsers as well. IE for example is
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# uploading files with "C:\foo\bar.txt" as filename
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value = value[1:-1]
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# if this is a filename and the starting characters look like
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# a UNC path, then just return the value without quotes. Using the
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# replace sequence below on a UNC path has the effect of turning
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# the leading double slash into a single slash and then
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# _fix_ie_filename() doesn't work correctly. See #458.
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if not is_filename or value[:2] != '\\\\':
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return value.replace('\\\\', '\\').replace('\\"', '"')
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return value
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def dict_from_cookiejar(cj):
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"""Returns a key/value dictionary from a CookieJar.
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:param cj: CookieJar object to extract cookies from.
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"""
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cookie_dict = {}
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for cookie in cj:
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cookie_dict[cookie.name] = cookie.value
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return cookie_dict
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def add_dict_to_cookiejar(cj, cookie_dict):
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"""Returns a CookieJar from a key/value dictionary.
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:param cj: CookieJar to insert cookies into.
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:param cookie_dict: Dict of key/values to insert into CookieJar.
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"""
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cj2 = cookiejar_from_dict(cookie_dict)
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cj.update(cj2)
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return cj
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def get_encodings_from_content(content):
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"""Returns encodings from given content string.
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:param content: bytestring to extract encodings from.
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"""
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charset_re = re.compile(r'<meta.*?charset=["\']*(.+?)["\'>]', flags=re.I)
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return charset_re.findall(content)
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def get_encoding_from_headers(headers):
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"""Returns encodings from given HTTP Header Dict.
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:param headers: dictionary to extract encoding from.
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"""
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content_type = headers.get('content-type')
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if not content_type:
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return None
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content_type, params = cgi.parse_header(content_type)
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if 'charset' in params:
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return params['charset'].strip("'\"")
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if 'text' in content_type:
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return 'ISO-8859-1'
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def stream_decode_response_unicode(iterator, r):
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"""Stream decodes a iterator."""
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if r.encoding is None:
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for item in iterator:
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yield item
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return
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decoder = codecs.getincrementaldecoder(r.encoding)(errors='replace')
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for chunk in iterator:
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rv = decoder.decode(chunk)
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if rv:
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yield rv
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rv = decoder.decode(b'', final=True)
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if rv:
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yield rv
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def iter_slices(string, slice_length):
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"""Iterate over slices of a string."""
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pos = 0
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while pos < len(string):
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yield string[pos:pos + slice_length]
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pos += slice_length
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def get_unicode_from_response(r):
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"""Returns the requested content back in unicode.
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:param r: Response object to get unicode content from.
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Tried:
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1. charset from content-type
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2. every encodings from ``<meta ... charset=XXX>``
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3. fall back and replace all unicode characters
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"""
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tried_encodings = []
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# Try charset from content-type
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encoding = get_encoding_from_headers(r.headers)
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if encoding:
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try:
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return str(r.content, encoding)
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except UnicodeError:
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tried_encodings.append(encoding)
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# Fall back:
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try:
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return str(r.content, encoding, errors='replace')
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except TypeError:
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return r.content
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# The unreserved URI characters (RFC 3986)
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UNRESERVED_SET = frozenset(
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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+ "0123456789-._~")
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def unquote_unreserved(uri):
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"""Un-escape any percent-escape sequences in a URI that are unreserved
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characters. This leaves all reserved, illegal and non-ASCII bytes encoded.
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"""
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parts = uri.split('%')
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for i in range(1, len(parts)):
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h = parts[i][0:2]
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if len(h) == 2 and h.isalnum():
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c = chr(int(h, 16))
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if c in UNRESERVED_SET:
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parts[i] = c + parts[i][2:]
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else:
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parts[i] = '%' + parts[i]
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else:
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parts[i] = '%' + parts[i]
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return ''.join(parts)
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def requote_uri(uri):
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"""Re-quote the given URI.
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This function passes the given URI through an unquote/quote cycle to
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ensure that it is fully and consistently quoted.
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"""
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# Unquote only the unreserved characters
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# Then quote only illegal characters (do not quote reserved, unreserved,
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# or '%')
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return quote(unquote_unreserved(uri), safe="!#$%&'()*+,/:;=?@[]~")
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def get_environ_proxies(url):
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"""Return a dict of environment proxies."""
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get_proxy = lambda k: os.environ.get(k) or os.environ.get(k.upper())
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# First check whether no_proxy is defined. If it is, check that the URL
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# we're getting isn't in the no_proxy list.
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no_proxy = get_proxy('no_proxy')
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netloc = urlparse(url).netloc
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if no_proxy:
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# We need to check whether we match here. We need to see if we match
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# the end of the netloc, both with and without the port.
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no_proxy = no_proxy.split(',')
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for host in no_proxy:
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if netloc.endswith(host) or netloc.split(':')[0].endswith(host):
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# The URL does match something in no_proxy, so we don't want
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# to apply the proxies on this URL.
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return {}
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# If the system proxy settings indicate that this URL should be bypassed,
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# don't proxy.
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if proxy_bypass(netloc):
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return {}
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# If we get here, we either didn't have no_proxy set or we're not going
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# anywhere that no_proxy applies to, and the system settings don't require
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# bypassing the proxy for the current URL.
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return getproxies()
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def default_user_agent():
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"""Return a string representing the default user agent."""
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_implementation = platform.python_implementation()
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if _implementation == 'CPython':
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_implementation_version = platform.python_version()
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elif _implementation == 'PyPy':
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_implementation_version = '%s.%s.%s' % (sys.pypy_version_info.major,
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sys.pypy_version_info.minor,
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sys.pypy_version_info.micro)
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if sys.pypy_version_info.releaselevel != 'final':
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_implementation_version = ''.join([_implementation_version, sys.pypy_version_info.releaselevel])
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elif _implementation == 'Jython':
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_implementation_version = platform.python_version() # Complete Guess
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elif _implementation == 'IronPython':
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_implementation_version = platform.python_version() # Complete Guess
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else:
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_implementation_version = 'Unknown'
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try:
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p_system = platform.system()
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p_release = platform.release()
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except IOError:
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p_system = 'Unknown'
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p_release = 'Unknown'
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return " ".join(['python-requests/%s' % __version__,
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'%s/%s' % (_implementation, _implementation_version),
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'%s/%s' % (p_system, p_release)])
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def default_headers():
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return CaseInsensitiveDict({
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'User-Agent': default_user_agent(),
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'Accept-Encoding': ', '.join(('gzip', 'deflate', 'compress')),
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'Accept': '*/*'
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})
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def parse_header_links(value):
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"""Return a dict of parsed link headers proxies.
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i.e. Link: <http:/.../front.jpeg>; rel=front; type="image/jpeg",<http://.../back.jpeg>; rel=back;type="image/jpeg"
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"""
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links = []
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replace_chars = " '\""
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for val in value.split(","):
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try:
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url, params = val.split(";", 1)
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except ValueError:
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url, params = val, ''
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link = {}
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link["url"] = url.strip("<> '\"")
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for param in params.split(";"):
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try:
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key, value = param.split("=")
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except ValueError:
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break
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link[key.strip(replace_chars)] = value.strip(replace_chars)
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links.append(link)
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return links
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# Null bytes; no need to recreate these on each call to guess_json_utf
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_null = '\x00'.encode('ascii') # encoding to ASCII for Python 3
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_null2 = _null * 2
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_null3 = _null * 3
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def guess_json_utf(data):
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# JSON always starts with two ASCII characters, so detection is as
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# easy as counting the nulls and from their location and count
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# determine the encoding. Also detect a BOM, if present.
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sample = data[:4]
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if sample in (codecs.BOM_UTF32_LE, codecs.BOM32_BE):
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return 'utf-32' # BOM included
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if sample[:3] == codecs.BOM_UTF8:
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return 'utf-8-sig' # BOM included, MS style (discouraged)
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if sample[:2] in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE):
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return 'utf-16' # BOM included
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nullcount = sample.count(_null)
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if nullcount == 0:
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return 'utf-8'
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if nullcount == 2:
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if sample[::2] == _null2: # 1st and 3rd are null
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return 'utf-16-be'
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if sample[1::2] == _null2: # 2nd and 4th are null
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return 'utf-16-le'
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# Did not detect 2 valid UTF-16 ascii-range characters
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if nullcount == 3:
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if sample[:3] == _null3:
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return 'utf-32-be'
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if sample[1:] == _null3:
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return 'utf-32-le'
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# Did not detect a valid UTF-32 ascii-range character
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return None
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def prepend_scheme_if_needed(url, new_scheme):
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'''Given a URL that may or may not have a scheme, prepend the given scheme.
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Does not replace a present scheme with the one provided as an argument.'''
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scheme, netloc, path, params, query, fragment = urlparse(url, new_scheme)
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# urlparse is a finicky beast, and sometimes decides that there isn't a
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# netloc present. Assume that it's being over-cautious, and switch netloc
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# and path if urlparse decided there was no netloc.
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if not netloc:
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netloc, path = path, netloc
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return urlunparse((scheme, netloc, path, params, query, fragment))
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def get_auth_from_url(url):
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"""Given a url with authentication components, extract them into a tuple of
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username,password."""
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if url:
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parsed = urlparse(url)
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return (parsed.username, parsed.password)
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else:
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return ('', '')
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