Source code for revproxy.utils


import re

import logging

from wsgiref.util import is_hop_by_hop

try:
    from http.cookies import SimpleCookie
    COOKIE_PREFIX = ''
except ImportError:
    from Cookie import SimpleCookie
    COOKIE_PREFIX = 'Set-Cookie: '


#: List containing string constant that are used to represent headers that can
#: be ignored in the required_header function
IGNORE_HEADERS = (
    'HTTP_ACCEPT_ENCODING',  # We want content to be uncompressed so
                             # we remove the Accept-Encoding from
                             # original request
    'HTTP_HOST',
    'HTTP_REMOTE_USER',
)


# Default from HTTP RFC 2616
#   See: http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
#: Variable that represent the default charset used
DEFAULT_CHARSET = 'latin-1'

#: List containing string constants that represents possible html content type
HTML_CONTENT_TYPES = (
    'text/html',
    'application/xhtml+xml'
)

#: Variable used to represent a minimal content size required for response
#: to be turned into stream
MIN_STREAMING_LENGTH = 4 * 1024  # 4KB

#: Regex used to find charset in a html content type
_get_charset_re = re.compile(r';\s*charset=(?P<charset>[^\s;]+)', re.I)



[docs]def is_html_content_type(content_type):
    """Function used to verify if the parameter is a proper html content type

    :param content_type: String variable that represent a content-type
    :returns:  A boolean value stating if the content_type is a valid html
               content type
    """
    for html_content_type in HTML_CONTENT_TYPES:
        if content_type.startswith(html_content_type):
            return True

    return False




[docs]def should_stream(proxy_response):
    """Function to verify if the proxy_response must be converted into
    a stream.This will be done by checking the proxy_response content-length
    and verify if its length is bigger than one stipulated
    by MIN_STREAMING_LENGTH.

    :param proxy_response: An Instance of urllib3.response.HTTPResponse
    :returns: A boolean stating if the proxy_response should
              be treated as a stream
    """
    content_type = proxy_response.headers.get('Content-Type')

    if is_html_content_type(content_type):
        return False

    try:
        content_length = int(proxy_response.headers.get('Content-Length', 0))
    except ValueError:
        content_length = 0

    if not content_length or content_length > MIN_STREAMING_LENGTH:
        return True

    return False




[docs]def get_charset(content_type):
    """Function used to retrieve the charset from a content-type.If there is no
    charset in the content type then the charset defined on DEFAULT_CHARSET
    will be returned

    :param  content_type:   A string containing a Content-Type header
    :returns:               A string containing the charset
    """
    if not content_type:
        return DEFAULT_CHARSET

    matched = _get_charset_re.search(content_type)
    if matched:
        # Extract the charset and strip its double quotes
        return matched.group('charset').replace('"', '')
    return DEFAULT_CHARSET




[docs]def required_header(header):
    """Function that verify if the header parameter is a essential header

    :param header:  A string represented a header
    :returns:       A boolean value that represent if the header is required
    """
    if header in IGNORE_HEADERS:
        return False

    if header.startswith('HTTP_') or header == 'CONTENT_TYPE':
        return True

    return False




[docs]def set_response_headers(response, response_headers):

    for header, value in response_headers.items():
        if is_hop_by_hop(header) or header.lower() == 'set-cookie':
            continue

        response[header.title()] = value

    logger.debug('Response headers: %s', getattr(response, '_headers'))




[docs]def normalize_request_headers(request):
    """Function used to transform header, replacing 'HTTP\_' to ''
    and replace '_' to '-'

    :param request:  A HttpRequest that will be transformed
    :returns:        A dictionary with the normalized headers
    """
    norm_headers = {}
    for header, value in request.META.items():
        if required_header(header):
            norm_header = header.replace('HTTP_', '').title().replace('_', '-')
            norm_headers[norm_header] = value

    return norm_headers




[docs]def encode_items(items):
    """Function that encode all elements in the list of items passed as
    a parameter

    :param items:  A list of tuple
    :returns:      A list of tuple with all items encoded in 'utf-8'
    """
    encoded = []
    for key, values in items:
        for value in values:
            encoded.append((key.encode('utf-8'), value.encode('utf-8')))
    return encoded



logger = logging.getLogger('revproxy.cookies')