363 lines
14 KiB
Python
363 lines
14 KiB
Python
try:
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from cStringIO import StringIO
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except ImportError:
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from StringIO import StringIO
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try:
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set
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except NameError:
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from sets import Set as set
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import struct
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import time
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import types
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import cherrypy
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from cherrypy.lib import file_generator
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from cherrypy.lib import set_vary_header
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def decode(encoding=None, default_encoding='utf-8'):
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"""Replace or extend the list of charsets used to decode a request entity.
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Either argument may be a single string or a list of strings.
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encoding: If not None, restricts the set of charsets attempted while decoding
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a request entity to the given set (even if a different charset is given in
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the Content-Type request header).
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default_encoding: Only in effect if the 'encoding' argument is not given.
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If given, the set of charsets attempted while decoding a request entity is
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*extended* with the given value(s).
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"""
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body = cherrypy.request.body
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if encoding is not None:
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if not isinstance(encoding, list):
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encoding = [encoding]
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body.attempt_charsets = encoding
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elif default_encoding:
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if not isinstance(default_encoding, list):
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default_encoding = [default_encoding]
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body.attempt_charsets = body.attempt_charsets + default_encoding
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class ResponseEncoder:
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default_encoding = 'utf-8'
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failmsg = "Response body could not be encoded with %r."
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encoding = None
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errors = 'strict'
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text_only = True
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add_charset = True
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debug = False
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def __init__(self, **kwargs):
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for k, v in kwargs.items():
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setattr(self, k, v)
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self.attempted_charsets = set()
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request = cherrypy.serving.request
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if request.handler is not None:
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# Replace request.handler with self
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if self.debug:
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cherrypy.log('Replacing request.handler', 'TOOLS.ENCODE')
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self.oldhandler = request.handler
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request.handler = self
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def encode_stream(self, encoding):
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"""Encode a streaming response body.
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Use a generator wrapper, and just pray it works as the stream is
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being written out.
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"""
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if encoding in self.attempted_charsets:
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return False
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self.attempted_charsets.add(encoding)
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def encoder(body):
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for chunk in body:
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if isinstance(chunk, unicode):
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chunk = chunk.encode(encoding, self.errors)
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yield chunk
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self.body = encoder(self.body)
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return True
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def encode_string(self, encoding):
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"""Encode a buffered response body."""
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if encoding in self.attempted_charsets:
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return False
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self.attempted_charsets.add(encoding)
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try:
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body = []
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for chunk in self.body:
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if isinstance(chunk, unicode):
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chunk = chunk.encode(encoding, self.errors)
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body.append(chunk)
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self.body = body
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except (LookupError, UnicodeError):
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return False
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else:
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return True
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def find_acceptable_charset(self):
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request = cherrypy.serving.request
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response = cherrypy.serving.response
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if self.debug:
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cherrypy.log('response.stream %r' % response.stream, 'TOOLS.ENCODE')
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if response.stream:
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encoder = self.encode_stream
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else:
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encoder = self.encode_string
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if "Content-Length" in response.headers:
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# Delete Content-Length header so finalize() recalcs it.
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# Encoded strings may be of different lengths from their
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# unicode equivalents, and even from each other. For example:
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# >>> t = u"\u7007\u3040"
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# >>> len(t)
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# 2
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# >>> len(t.encode("UTF-8"))
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# 6
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# >>> len(t.encode("utf7"))
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# 8
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del response.headers["Content-Length"]
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# Parse the Accept-Charset request header, and try to provide one
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# of the requested charsets (in order of user preference).
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encs = request.headers.elements('Accept-Charset')
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charsets = [enc.value.lower() for enc in encs]
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if self.debug:
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cherrypy.log('charsets %s' % repr(charsets), 'TOOLS.ENCODE')
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if self.encoding is not None:
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# If specified, force this encoding to be used, or fail.
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encoding = self.encoding.lower()
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if self.debug:
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cherrypy.log('Specified encoding %r' % encoding, 'TOOLS.ENCODE')
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if (not charsets) or "*" in charsets or encoding in charsets:
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if self.debug:
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cherrypy.log('Attempting encoding %r' % encoding, 'TOOLS.ENCODE')
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if encoder(encoding):
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return encoding
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else:
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if not encs:
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if self.debug:
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cherrypy.log('Attempting default encoding %r' %
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self.default_encoding, 'TOOLS.ENCODE')
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# Any character-set is acceptable.
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if encoder(self.default_encoding):
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return self.default_encoding
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else:
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raise cherrypy.HTTPError(500, self.failmsg % self.default_encoding)
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else:
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if "*" not in charsets:
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# If no "*" is present in an Accept-Charset field, then all
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# character sets not explicitly mentioned get a quality
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# value of 0, except for ISO-8859-1, which gets a quality
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# value of 1 if not explicitly mentioned.
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iso = 'iso-8859-1'
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if iso not in charsets:
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if self.debug:
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cherrypy.log('Attempting ISO-8859-1 encoding',
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'TOOLS.ENCODE')
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if encoder(iso):
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return iso
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for element in encs:
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if element.qvalue > 0:
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if element.value == "*":
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# Matches any charset. Try our default.
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if self.debug:
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cherrypy.log('Attempting default encoding due '
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'to %r' % element, 'TOOLS.ENCODE')
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if encoder(self.default_encoding):
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return self.default_encoding
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else:
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encoding = element.value
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if self.debug:
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cherrypy.log('Attempting encoding %r (qvalue >'
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'0)' % element, 'TOOLS.ENCODE')
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if encoder(encoding):
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return encoding
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# No suitable encoding found.
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ac = request.headers.get('Accept-Charset')
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if ac is None:
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msg = "Your client did not send an Accept-Charset header."
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else:
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msg = "Your client sent this Accept-Charset header: %s." % ac
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msg += " We tried these charsets: %s." % ", ".join(self.attempted_charsets)
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raise cherrypy.HTTPError(406, msg)
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def __call__(self, *args, **kwargs):
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response = cherrypy.serving.response
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self.body = self.oldhandler(*args, **kwargs)
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if isinstance(self.body, basestring):
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# strings get wrapped in a list because iterating over a single
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# item list is much faster than iterating over every character
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# in a long string.
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if self.body:
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self.body = [self.body]
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else:
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# [''] doesn't evaluate to False, so replace it with [].
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self.body = []
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elif isinstance(self.body, types.FileType):
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self.body = file_generator(self.body)
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elif self.body is None:
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self.body = []
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ct = response.headers.elements("Content-Type")
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if self.debug:
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cherrypy.log('Content-Type: %r' % ct, 'TOOLS.ENCODE')
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if ct:
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if self.text_only:
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ct = ct[0]
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if ct.value.lower().startswith("text/"):
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if self.debug:
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cherrypy.log('Content-Type %r starts with "text/"' % ct,
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'TOOLS.ENCODE')
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do_find = True
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else:
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if self.debug:
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cherrypy.log('Not finding because Content-Type %r does '
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'not start with "text/"' % ct,
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'TOOLS.ENCODE')
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do_find = False
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else:
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if self.debug:
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cherrypy.log('Finding because not text_only', 'TOOLS.ENCODE')
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do_find = True
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if do_find:
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# Set "charset=..." param on response Content-Type header
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ct.params['charset'] = self.find_acceptable_charset()
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if self.add_charset:
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if self.debug:
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cherrypy.log('Setting Content-Type %r' % ct,
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'TOOLS.ENCODE')
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response.headers["Content-Type"] = str(ct)
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return self.body
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# GZIP
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def compress(body, compress_level):
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"""Compress 'body' at the given compress_level."""
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import zlib
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# See http://www.gzip.org/zlib/rfc-gzip.html
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yield '\x1f\x8b' # ID1 and ID2: gzip marker
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yield '\x08' # CM: compression method
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yield '\x00' # FLG: none set
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# MTIME: 4 bytes
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yield struct.pack("<L", int(time.time()) & 0xFFFFFFFFL)
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yield '\x02' # XFL: max compression, slowest algo
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yield '\xff' # OS: unknown
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crc = zlib.crc32("")
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size = 0
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zobj = zlib.compressobj(compress_level,
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zlib.DEFLATED, -zlib.MAX_WBITS,
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zlib.DEF_MEM_LEVEL, 0)
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for line in body:
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size += len(line)
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crc = zlib.crc32(line, crc)
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yield zobj.compress(line)
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yield zobj.flush()
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# CRC32: 4 bytes
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yield struct.pack("<L", crc & 0xFFFFFFFFL)
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# ISIZE: 4 bytes
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yield struct.pack("<L", size & 0xFFFFFFFFL)
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def decompress(body):
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import gzip
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zbuf = StringIO()
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zbuf.write(body)
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zbuf.seek(0)
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zfile = gzip.GzipFile(mode='rb', fileobj=zbuf)
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data = zfile.read()
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zfile.close()
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return data
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def gzip(compress_level=5, mime_types=['text/html', 'text/plain'], debug=False):
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"""Try to gzip the response body if Content-Type in mime_types.
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cherrypy.response.headers['Content-Type'] must be set to one of the
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values in the mime_types arg before calling this function.
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No compression is performed if any of the following hold:
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* The client sends no Accept-Encoding request header
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* No 'gzip' or 'x-gzip' is present in the Accept-Encoding header
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* No 'gzip' or 'x-gzip' with a qvalue > 0 is present
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* The 'identity' value is given with a qvalue > 0.
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"""
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request = cherrypy.serving.request
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response = cherrypy.serving.response
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set_vary_header(response, "Accept-Encoding")
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if not response.body:
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# Response body is empty (might be a 304 for instance)
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if debug:
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cherrypy.log('No response body', context='TOOLS.GZIP')
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return
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# If returning cached content (which should already have been gzipped),
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# don't re-zip.
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if getattr(request, "cached", False):
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if debug:
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cherrypy.log('Not gzipping cached response', context='TOOLS.GZIP')
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return
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acceptable = request.headers.elements('Accept-Encoding')
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if not acceptable:
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# If no Accept-Encoding field is present in a request,
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# the server MAY assume that the client will accept any
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# content coding. In this case, if "identity" is one of
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# the available content-codings, then the server SHOULD use
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# the "identity" content-coding, unless it has additional
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# information that a different content-coding is meaningful
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# to the client.
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if debug:
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cherrypy.log('No Accept-Encoding', context='TOOLS.GZIP')
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return
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ct = response.headers.get('Content-Type', '').split(';')[0]
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for coding in acceptable:
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if coding.value == 'identity' and coding.qvalue != 0:
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if debug:
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cherrypy.log('Non-zero identity qvalue: %r' % coding,
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context='TOOLS.GZIP')
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return
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if coding.value in ('gzip', 'x-gzip'):
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if coding.qvalue == 0:
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if debug:
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cherrypy.log('Zero gzip qvalue: %r' % coding,
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context='TOOLS.GZIP')
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return
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if ct not in mime_types:
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if debug:
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cherrypy.log('Content-Type %r not in mime_types %r' %
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(ct, mime_types), context='TOOLS.GZIP')
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return
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if debug:
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cherrypy.log('Gzipping', context='TOOLS.GZIP')
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# Return a generator that compresses the page
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response.headers['Content-Encoding'] = 'gzip'
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response.body = compress(response.body, compress_level)
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if "Content-Length" in response.headers:
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# Delete Content-Length header so finalize() recalcs it.
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del response.headers["Content-Length"]
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return
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if debug:
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cherrypy.log('No acceptable encoding found.', context='GZIP')
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cherrypy.HTTPError(406, "identity, gzip").set_response()
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