Add 'requests' library to third_party.

third_party/requests/utils.py

Index: third_party/requests/utils.py
diff --git a/third_party/requests/utils.py b/third_party/requests/utils.py
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+++ b/third_party/requests/utils.py
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+# -*- 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 os
+import platform
+import re
+import sys
+from netrc import netrc, NetrcParseError
+
+from . import __version__
+from . import certs
+from .compat import parse_http_list as _parse_list_header
+from .compat import quote, urlparse, bytes, str, OrderedDict, urlunparse
+from .cookies import RequestsCookieJar, cookiejar_from_dict
+from .structures import CaseInsensitiveDict
+
+_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'):
+        return os.fstat(o.fileno()).st_size
+
+
+def get_netrc_auth(url):
+    """Returns the Requests tuple auth for a given url from netrc."""
+
+    try:
+        locations = (os.path.expanduser('~/{0}'.format(f)) for f in NETRC_FILES)
+        netrc_path = None
+
+        for loc in locations:
+            if os.path.exists(loc) and not netrc_path:
+                netrc_path = loc
+
+        # Abort early if there isn't one.
+        if netrc_path is None:
+            return netrc_path
+
+        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'<meta.*?charset=["\']*(.+?)["\'>]', flags=re.I)
+
+    return charset_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('', 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 ``<meta ... charset=XXX>``
+
+    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():
+            c = chr(int(h, 16))
+            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 get_environ_proxies(url):
+    """Return a dict of environment proxies."""
+
+    proxy_keys = [
+        'all',
+        'http',
+        'https',
+        'ftp',
+        'socks'
+    ]
+
+    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')
+
+    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.split(',')
+        netloc = urlparse(url).netloc
+
+        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 {}
+
+    # If we get here, we either didn't have no_proxy set or we're not going
+    # anywhere that no_proxy applies to.
+    proxies = [(key, get_proxy(key + '_proxy')) for key in proxy_keys]
+    return dict([(key, val) for (key, val) in proxies if val])
+
+
+def default_user_agent():
+    """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(['python-requests/%s' % __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', 'compress')),
+        'Accept': '*/*'
+    })
+
+
+def parse_header_links(value):
+    """Return a dict of parsed link headers proxies.
+
+    i.e. Link: <http:/.../front.jpeg>; rel=front; type="image/jpeg",<http://.../back.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."""
+    if url:
+        parsed = urlparse(url)
+        return (parsed.username, parsed.password)
+    else:
+        return ('', '')