226 lines
6.9 KiB
Python
226 lines
6.9 KiB
Python
"""Utils from django-revproxy, slightly adjusted"""
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import logging
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import re
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from wsgiref.util import is_hop_by_hop
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try:
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from http.cookies import SimpleCookie
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COOKIE_PREFIX = ''
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except ImportError:
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from Cookie import SimpleCookie
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COOKIE_PREFIX = 'Set-Cookie: '
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#: List containing string constant that are used to represent headers that can
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#: be ignored in the required_header function
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IGNORE_HEADERS = (
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'HTTP_ACCEPT_ENCODING', # We want content to be uncompressed so
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# we remove the Accept-Encoding from
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# original request
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'HTTP_HOST',
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'HTTP_REMOTE_USER',
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)
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# Default from HTTP RFC 2616
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# See: http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
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#: Variable that represent the default charset used
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DEFAULT_CHARSET = 'latin-1'
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#: List containing string constants that represents possible html content type
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HTML_CONTENT_TYPES = (
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'text/html',
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'application/xhtml+xml'
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)
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#: Variable used to represent a minimal content size required for response
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#: to be turned into stream
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MIN_STREAMING_LENGTH = 4 * 1024 # 4KB
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#: Regex used to find charset in a html content type
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_get_charset_re = re.compile(r';\s*charset=(?P<charset>[^\s;]+)', re.I)
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def is_html_content_type(content_type):
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"""Function used to verify if the parameter is a proper html content type
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:param content_type: String variable that represent a content-type
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:returns: A boolean value stating if the content_type is a valid html
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content type
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"""
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for html_content_type in HTML_CONTENT_TYPES:
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if content_type.startswith(html_content_type):
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return True
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return False
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def should_stream(proxy_response):
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"""Function to verify if the proxy_response must be converted into
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a stream.This will be done by checking the proxy_response content-length
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and verify if its length is bigger than one stipulated
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by MIN_STREAMING_LENGTH.
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:param proxy_response: An Instance of urllib3.response.HTTPResponse
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:returns: A boolean stating if the proxy_response should
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be treated as a stream
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"""
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content_type = proxy_response.headers.get('Content-Type')
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if is_html_content_type(content_type):
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return False
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try:
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content_length = int(proxy_response.headers.get('Content-Length', 0))
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except ValueError:
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content_length = 0
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if not content_length or content_length > MIN_STREAMING_LENGTH:
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return True
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return False
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def get_charset(content_type):
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"""Function used to retrieve the charset from a content-type.If there is no
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charset in the content type then the charset defined on DEFAULT_CHARSET
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will be returned
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:param content_type: A string containing a Content-Type header
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:returns: A string containing the charset
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"""
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if not content_type:
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return DEFAULT_CHARSET
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matched = _get_charset_re.search(content_type)
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if matched:
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# Extract the charset and strip its double quotes
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return matched.group('charset').replace('"', '')
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return DEFAULT_CHARSET
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def required_header(header):
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"""Function that verify if the header parameter is a essential header
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:param header: A string represented a header
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:returns: A boolean value that represent if the header is required
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"""
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if header in IGNORE_HEADERS:
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return False
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if header.startswith('HTTP_') or header == 'CONTENT_TYPE':
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return True
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return False
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def set_response_headers(response, response_headers):
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"""Set response's header"""
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for header, value in response_headers.items():
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if is_hop_by_hop(header) or header.lower() == 'set-cookie':
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continue
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response[header.title()] = value
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logger.debug('Response headers: %s', getattr(response, '_headers'))
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def normalize_request_headers(request):
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"""Function used to transform header, replacing 'HTTP\\_' to ''
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and replace '_' to '-'
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:param request: A HttpRequest that will be transformed
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:returns: A dictionary with the normalized headers
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"""
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norm_headers = {}
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for header, value in request.META.items():
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if required_header(header):
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norm_header = header.replace('HTTP_', '').title().replace('_', '-')
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norm_headers[norm_header] = value
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return norm_headers
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def encode_items(items):
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"""Function that encode all elements in the list of items passed as
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a parameter
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:param items: A list of tuple
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:returns: A list of tuple with all items encoded in 'utf-8'
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"""
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encoded = []
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for key, values in items:
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for value in values:
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encoded.append((key.encode('utf-8'), value.encode('utf-8')))
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return encoded
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logger = logging.getLogger('revproxy.cookies')
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def cookie_from_string(cookie_string, strict_cookies=False):
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"""Parser for HTTP header set-cookie
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The return from this function will be used as parameters for
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django's response.set_cookie method. Because set_cookie doesn't
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have parameter comment, this cookie attribute will be ignored.
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:param cookie_string: A string representing a valid cookie
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:param strict_cookies: Whether to only accept RFC-compliant cookies
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:returns: A dictionary containing the cookie_string attributes
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"""
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if strict_cookies:
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cookies = SimpleCookie(COOKIE_PREFIX + cookie_string)
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if not cookies.keys():
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return None
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cookie_name, = cookies.keys()
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cookie_dict = {k: v for k, v in cookies[cookie_name].items()
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if v and k != 'comment'}
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cookie_dict['key'] = cookie_name
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cookie_dict['value'] = cookies[cookie_name].value
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return cookie_dict
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valid_attrs = ('path', 'domain', 'comment', 'expires',
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'max_age', 'httponly', 'secure')
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cookie_dict = {}
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cookie_parts = cookie_string.split(';')
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try:
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cookie_dict['key'], cookie_dict['value'] = \
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cookie_parts[0].split('=', 1)
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cookie_dict['value'] = cookie_dict['value'].replace('"', '')
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except ValueError:
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logger.warning('Invalid cookie: `%s`', cookie_string)
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return None
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if cookie_dict['value'].startswith('='):
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logger.warning('Invalid cookie: `%s`', cookie_string)
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return None
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for part in cookie_parts[1:]:
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if '=' in part:
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attr, value = part.split('=', 1)
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value = value.strip()
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else:
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attr = part
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value = ''
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attr = attr.strip().lower()
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if not attr:
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continue
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if attr in valid_attrs:
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if attr in ('httponly', 'secure'):
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cookie_dict[attr] = True
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elif attr in 'comment':
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# ignoring comment attr as explained in the
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# function docstring
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continue
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else:
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cookie_dict[attr] = value
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else:
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logger.warning('Unknown cookie attribute %s', attr)
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return cookie_dict
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