# -*- coding: utf-8 -*- """ requests.utils ~~~~~~~~~~~~~~ This module provides utility functions that are used within Requests that are also useful for external consumption. """ import cgi import codecs import collections import io import os import platform import re import sys import socket import struct from . import __version__ from . import certs from .compat import parse_http_list as _parse_list_header from .compat import (quote, urlparse, bytes, str, OrderedDict, unquote, is_py2, builtin_str, getproxies, proxy_bypass, urlunparse) from .cookies import RequestsCookieJar, cookiejar_from_dict from .structures import CaseInsensitiveDict from .exceptions import InvalidURL _hush_pyflakes = (RequestsCookieJar,) NETRC_FILES = ('.netrc', '_netrc') DEFAULT_CA_BUNDLE_PATH = certs.where() def dict_to_sequence(d): """Returns an internal sequence dictionary update.""" if hasattr(d, 'items'): d = d.items() return d def super_len(o): if hasattr(o, '__len__'): return len(o) if hasattr(o, 'len'): return o.len if hasattr(o, 'fileno'): try: fileno = o.fileno() except io.UnsupportedOperation: pass else: return os.fstat(fileno).st_size if hasattr(o, 'getvalue'): # e.g. BytesIO, cStringIO.StringIO return len(o.getvalue()) def get_netrc_auth(url): """Returns the Requests tuple auth for a given url from netrc.""" try: from netrc import netrc, NetrcParseError netrc_path = None for f in NETRC_FILES: try: loc = os.path.expanduser('~/{0}'.format(f)) except KeyError: # os.path.expanduser can fail when $HOME is undefined and # getpwuid fails. See http://bugs.python.org/issue20164 & # https://github.com/kennethreitz/requests/issues/1846 return if os.path.exists(loc): netrc_path = loc break # Abort early if there isn't one. if netrc_path is None: return ri = urlparse(url) # Strip port numbers from netloc host = ri.netloc.split(':')[0] try: _netrc = netrc(netrc_path).authenticators(host) if _netrc: # Return with login / password login_i = (0 if _netrc[0] else 1) return (_netrc[login_i], _netrc[2]) except (NetrcParseError, IOError): # If there was a parsing error or a permissions issue reading the file, # we'll just skip netrc auth pass # AppEngine hackiness. except (ImportError, AttributeError): pass def guess_filename(obj): """Tries to guess the filename of the given object.""" name = getattr(obj, 'name', None) if name and name[0] != '<' and name[-1] != '>': return os.path.basename(name) def from_key_val_list(value): """Take an object and test to see if it can be represented as a dictionary. Unless it can not be represented as such, return an OrderedDict, e.g., :: >>> from_key_val_list([('key', 'val')]) OrderedDict([('key', 'val')]) >>> from_key_val_list('string') ValueError: need more than 1 value to unpack >>> from_key_val_list({'key': 'val'}) OrderedDict([('key', 'val')]) """ if value is None: return None if isinstance(value, (str, bytes, bool, int)): raise ValueError('cannot encode objects that are not 2-tuples') return OrderedDict(value) def to_key_val_list(value): """Take an object and test to see if it can be represented as a dictionary. If it can be, return a list of tuples, e.g., :: >>> to_key_val_list([('key', 'val')]) [('key', 'val')] >>> to_key_val_list({'key': 'val'}) [('key', 'val')] >>> to_key_val_list('string') ValueError: cannot encode objects that are not 2-tuples. """ if value is None: return None if isinstance(value, (str, bytes, bool, int)): raise ValueError('cannot encode objects that are not 2-tuples') if isinstance(value, collections.Mapping): value = value.items() return list(value) # From mitsuhiko/werkzeug (used with permission). def parse_list_header(value): """Parse lists as described by RFC 2068 Section 2. In particular, parse comma-separated lists where the elements of the list may include quoted-strings. A quoted-string could contain a comma. A non-quoted string could have quotes in the middle. Quotes are removed automatically after parsing. It basically works like :func:`parse_set_header` just that items may appear multiple times and case sensitivity is preserved. The return value is a standard :class:`list`: >>> parse_list_header('token, "quoted value"') ['token', 'quoted value'] To create a header from the :class:`list` again, use the :func:`dump_header` function. :param value: a string with a list header. :return: :class:`list` """ result = [] for item in _parse_list_header(value): if item[:1] == item[-1:] == '"': item = unquote_header_value(item[1:-1]) result.append(item) return result # From mitsuhiko/werkzeug (used with permission). def parse_dict_header(value): """Parse lists of key, value pairs as described by RFC 2068 Section 2 and convert them into a python dict: >>> d = parse_dict_header('foo="is a fish", bar="as well"') >>> type(d) is dict True >>> sorted(d.items()) [('bar', 'as well'), ('foo', 'is a fish')] If there is no value for a key it will be `None`: >>> parse_dict_header('key_without_value') {'key_without_value': None} To create a header from the :class:`dict` again, use the :func:`dump_header` function. :param value: a string with a dict header. :return: :class:`dict` """ result = {} for item in _parse_list_header(value): if '=' not in item: result[item] = None continue name, value = item.split('=', 1) if value[:1] == value[-1:] == '"': value = unquote_header_value(value[1:-1]) result[name] = value return result # From mitsuhiko/werkzeug (used with permission). def unquote_header_value(value, is_filename=False): r"""Unquotes a header value. (Reversal of :func:`quote_header_value`). This does not use the real unquoting but what browsers are actually using for quoting. :param value: the header value to unquote. """ if value and value[0] == value[-1] == '"': # this is not the real unquoting, but fixing this so that the # RFC is met will result in bugs with internet explorer and # probably some other browsers as well. IE for example is # uploading files with "C:\foo\bar.txt" as filename value = value[1:-1] # if this is a filename and the starting characters look like # a UNC path, then just return the value without quotes. Using the # replace sequence below on a UNC path has the effect of turning # the leading double slash into a single slash and then # _fix_ie_filename() doesn't work correctly. See #458. if not is_filename or value[:2] != '\\\\': return value.replace('\\\\', '\\').replace('\\"', '"') return value def dict_from_cookiejar(cj): """Returns a key/value dictionary from a CookieJar. :param cj: CookieJar object to extract cookies from. """ cookie_dict = {} for cookie in cj: cookie_dict[cookie.name] = cookie.value return cookie_dict def add_dict_to_cookiejar(cj, cookie_dict): """Returns a CookieJar from a key/value dictionary. :param cj: CookieJar to insert cookies into. :param cookie_dict: Dict of key/values to insert into CookieJar. """ cj2 = cookiejar_from_dict(cookie_dict) cj.update(cj2) return cj def get_encodings_from_content(content): """Returns encodings from given content string. :param content: bytestring to extract encodings from. """ charset_re = re.compile(r']', flags=re.I) pragma_re = re.compile(r']', flags=re.I) xml_re = re.compile(r'^<\?xml.*?encoding=["\']*(.+?)["\'>]') return (charset_re.findall(content) + pragma_re.findall(content) + xml_re.findall(content)) def get_encoding_from_headers(headers): """Returns encodings from given HTTP Header Dict. :param headers: dictionary to extract encoding from. """ content_type = headers.get('content-type') if not content_type: return None content_type, params = cgi.parse_header(content_type) if 'charset' in params: return params['charset'].strip("'\"") if 'text' in content_type: return 'ISO-8859-1' def stream_decode_response_unicode(iterator, r): """Stream decodes a iterator.""" if r.encoding is None: for item in iterator: yield item return decoder = codecs.getincrementaldecoder(r.encoding)(errors='replace') for chunk in iterator: rv = decoder.decode(chunk) if rv: yield rv rv = decoder.decode(b'', final=True) if rv: yield rv def iter_slices(string, slice_length): """Iterate over slices of a string.""" pos = 0 while pos < len(string): yield string[pos:pos + slice_length] pos += slice_length def get_unicode_from_response(r): """Returns the requested content back in unicode. :param r: Response object to get unicode content from. Tried: 1. charset from content-type 2. every encodings from ```` 3. fall back and replace all unicode characters """ tried_encodings = [] # Try charset from content-type encoding = get_encoding_from_headers(r.headers) if encoding: try: return str(r.content, encoding) except UnicodeError: tried_encodings.append(encoding) # Fall back: try: return str(r.content, encoding, errors='replace') except TypeError: return r.content # The unreserved URI characters (RFC 3986) UNRESERVED_SET = frozenset( "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" + "0123456789-._~") def unquote_unreserved(uri): """Un-escape any percent-escape sequences in a URI that are unreserved characters. This leaves all reserved, illegal and non-ASCII bytes encoded. """ parts = uri.split('%') for i in range(1, len(parts)): h = parts[i][0:2] if len(h) == 2 and h.isalnum(): try: c = chr(int(h, 16)) except ValueError: raise InvalidURL("Invalid percent-escape sequence: '%s'" % h) if c in UNRESERVED_SET: parts[i] = c + parts[i][2:] else: parts[i] = '%' + parts[i] else: parts[i] = '%' + parts[i] return ''.join(parts) def requote_uri(uri): """Re-quote the given URI. This function passes the given URI through an unquote/quote cycle to ensure that it is fully and consistently quoted. """ # Unquote only the unreserved characters # Then quote only illegal characters (do not quote reserved, unreserved, # or '%') return quote(unquote_unreserved(uri), safe="!#$%&'()*+,/:;=?@[]~") def address_in_network(ip, net): """ This function allows you to check if on IP belongs to a network subnet Example: returns True if ip = 192.168.1.1 and net = 192.168.1.0/24 returns False if ip = 192.168.1.1 and net = 192.168.100.0/24 """ ipaddr = struct.unpack('=L', socket.inet_aton(ip))[0] netaddr, bits = net.split('/') netmask = struct.unpack('=L', socket.inet_aton(dotted_netmask(int(bits))))[0] network = struct.unpack('=L', socket.inet_aton(netaddr))[0] & netmask return (ipaddr & netmask) == (network & netmask) def dotted_netmask(mask): """ Converts mask from /xx format to xxx.xxx.xxx.xxx Example: if mask is 24 function returns 255.255.255.0 """ bits = 0xffffffff ^ (1 << 32 - mask) - 1 return socket.inet_ntoa(struct.pack('>I', bits)) def is_ipv4_address(string_ip): try: socket.inet_aton(string_ip) except socket.error: return False return True def is_valid_cidr(string_network): """Very simple check of the cidr format in no_proxy variable""" if string_network.count('/') == 1: try: mask = int(string_network.split('/')[1]) except ValueError: return False if mask < 1 or mask > 32: return False try: socket.inet_aton(string_network.split('/')[0]) except socket.error: return False else: return False return True def should_bypass_proxies(url): """ Returns whether we should bypass proxies or not. """ get_proxy = lambda k: os.environ.get(k) or os.environ.get(k.upper()) # First check whether no_proxy is defined. If it is, check that the URL # we're getting isn't in the no_proxy list. no_proxy = get_proxy('no_proxy') netloc = urlparse(url).netloc if no_proxy: # We need to check whether we match here. We need to see if we match # the end of the netloc, both with and without the port. no_proxy = no_proxy.replace(' ', '').split(',') ip = netloc.split(':')[0] if is_ipv4_address(ip): for proxy_ip in no_proxy: if is_valid_cidr(proxy_ip): if address_in_network(ip, proxy_ip): return True else: for host in no_proxy: if netloc.endswith(host) or netloc.split(':')[0].endswith(host): # The URL does match something in no_proxy, so we don't want # to apply the proxies on this URL. return True # If the system proxy settings indicate that this URL should be bypassed, # don't proxy. # The proxy_bypass function is incredibly buggy on OS X in early versions # of Python 2.6, so allow this call to fail. Only catch the specific # exceptions we've seen, though: this call failing in other ways can reveal # legitimate problems. try: bypass = proxy_bypass(netloc) except (TypeError, socket.gaierror): bypass = False if bypass: return True return False def get_environ_proxies(url): """Return a dict of environment proxies.""" if should_bypass_proxies(url): return {} else: return getproxies() def default_user_agent(name="python-requests"): """Return a string representing the default user agent.""" _implementation = platform.python_implementation() if _implementation == 'CPython': _implementation_version = platform.python_version() elif _implementation == 'PyPy': _implementation_version = '%s.%s.%s' % (sys.pypy_version_info.major, sys.pypy_version_info.minor, sys.pypy_version_info.micro) if sys.pypy_version_info.releaselevel != 'final': _implementation_version = ''.join([_implementation_version, sys.pypy_version_info.releaselevel]) elif _implementation == 'Jython': _implementation_version = platform.python_version() # Complete Guess elif _implementation == 'IronPython': _implementation_version = platform.python_version() # Complete Guess else: _implementation_version = 'Unknown' try: p_system = platform.system() p_release = platform.release() except IOError: p_system = 'Unknown' p_release = 'Unknown' return " ".join(['%s/%s' % (name, __version__), '%s/%s' % (_implementation, _implementation_version), '%s/%s' % (p_system, p_release)]) def default_headers(): return CaseInsensitiveDict({ 'User-Agent': default_user_agent(), 'Accept-Encoding': ', '.join(('gzip', 'deflate')), 'Accept': '*/*' }) def parse_header_links(value): """Return a dict of parsed link headers proxies. i.e. Link: ; rel=front; type="image/jpeg",; rel=back;type="image/jpeg" """ links = [] replace_chars = " '\"" for val in value.split(","): try: url, params = val.split(";", 1) except ValueError: url, params = val, '' link = {} link["url"] = url.strip("<> '\"") for param in params.split(";"): try: key, value = param.split("=") except ValueError: break link[key.strip(replace_chars)] = value.strip(replace_chars) links.append(link) return links # Null bytes; no need to recreate these on each call to guess_json_utf _null = '\x00'.encode('ascii') # encoding to ASCII for Python 3 _null2 = _null * 2 _null3 = _null * 3 def guess_json_utf(data): # JSON always starts with two ASCII characters, so detection is as # easy as counting the nulls and from their location and count # determine the encoding. Also detect a BOM, if present. sample = data[:4] if sample in (codecs.BOM_UTF32_LE, codecs.BOM32_BE): return 'utf-32' # BOM included if sample[:3] == codecs.BOM_UTF8: return 'utf-8-sig' # BOM included, MS style (discouraged) if sample[:2] in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE): return 'utf-16' # BOM included nullcount = sample.count(_null) if nullcount == 0: return 'utf-8' if nullcount == 2: if sample[::2] == _null2: # 1st and 3rd are null return 'utf-16-be' if sample[1::2] == _null2: # 2nd and 4th are null return 'utf-16-le' # Did not detect 2 valid UTF-16 ascii-range characters if nullcount == 3: if sample[:3] == _null3: return 'utf-32-be' if sample[1:] == _null3: return 'utf-32-le' # Did not detect a valid UTF-32 ascii-range character return None def prepend_scheme_if_needed(url, new_scheme): '''Given a URL that may or may not have a scheme, prepend the given scheme. Does not replace a present scheme with the one provided as an argument.''' scheme, netloc, path, params, query, fragment = urlparse(url, new_scheme) # urlparse is a finicky beast, and sometimes decides that there isn't a # netloc present. Assume that it's being over-cautious, and switch netloc # and path if urlparse decided there was no netloc. if not netloc: netloc, path = path, netloc return urlunparse((scheme, netloc, path, params, query, fragment)) def get_auth_from_url(url): """Given a url with authentication components, extract them into a tuple of username,password.""" parsed = urlparse(url) try: auth = (unquote(parsed.username), unquote(parsed.password)) except (AttributeError, TypeError): auth = ('', '') return auth def to_native_string(string, encoding='ascii'): """ Given a string object, regardless of type, returns a representation of that string in the native string type, encoding and decoding where necessary. This assumes ASCII unless told otherwise. """ out = None if isinstance(string, builtin_str): out = string else: if is_py2: out = string.encode(encoding) else: out = string.decode(encoding) return out