import struct import time import cherrypy from cherrypy._cpcompat import basestring, BytesIO, ntob, set, unicodestr from cherrypy.lib import file_generator from cherrypy.lib import set_vary_header def decode(encoding=None, default_encoding='utf-8'): """Replace or extend the list of charsets used to decode a request entity. Either argument may be a single string or a list of strings. encoding If not None, restricts the set of charsets attempted while decoding a request entity to the given set (even if a different charset is given in the Content-Type request header). default_encoding Only in effect if the 'encoding' argument is not given. If given, the set of charsets attempted while decoding a request entity is *extended* with the given value(s). """ body = cherrypy.request.body if encoding is not None: if not isinstance(encoding, list): encoding = [encoding] body.attempt_charsets = encoding elif default_encoding: if not isinstance(default_encoding, list): default_encoding = [default_encoding] body.attempt_charsets = body.attempt_charsets + default_encoding class ResponseEncoder: default_encoding = 'utf-8' failmsg = "Response body could not be encoded with %r." encoding = None errors = 'strict' text_only = True add_charset = True debug = False def __init__(self, **kwargs): for k, v in kwargs.items(): setattr(self, k, v) self.attempted_charsets = set() request = cherrypy.serving.request if request.handler is not None: # Replace request.handler with self if self.debug: cherrypy.log('Replacing request.handler', 'TOOLS.ENCODE') self.oldhandler = request.handler request.handler = self def encode_stream(self, encoding): """Encode a streaming response body. Use a generator wrapper, and just pray it works as the stream is being written out. """ if encoding in self.attempted_charsets: return False self.attempted_charsets.add(encoding) def encoder(body): for chunk in body: if isinstance(chunk, unicodestr): chunk = chunk.encode(encoding, self.errors) yield chunk self.body = encoder(self.body) return True def encode_string(self, encoding): """Encode a buffered response body.""" if encoding in self.attempted_charsets: return False self.attempted_charsets.add(encoding) try: body = [] for chunk in self.body: if isinstance(chunk, unicodestr): chunk = chunk.encode(encoding, self.errors) body.append(chunk) self.body = body except (LookupError, UnicodeError): return False else: return True def find_acceptable_charset(self): request = cherrypy.serving.request response = cherrypy.serving.response if self.debug: cherrypy.log('response.stream %r' % response.stream, 'TOOLS.ENCODE') if response.stream: encoder = self.encode_stream else: encoder = self.encode_string if "Content-Length" in response.headers: # Delete Content-Length header so finalize() recalcs it. # Encoded strings may be of different lengths from their # unicode equivalents, and even from each other. For example: # >>> t = u"\u7007\u3040" # >>> len(t) # 2 # >>> len(t.encode("UTF-8")) # 6 # >>> len(t.encode("utf7")) # 8 del response.headers["Content-Length"] # Parse the Accept-Charset request header, and try to provide one # of the requested charsets (in order of user preference). encs = request.headers.elements('Accept-Charset') charsets = [enc.value.lower() for enc in encs] if self.debug: cherrypy.log('charsets %s' % repr(charsets), 'TOOLS.ENCODE') if self.encoding is not None: # If specified, force this encoding to be used, or fail. encoding = self.encoding.lower() if self.debug: cherrypy.log('Specified encoding %r' % encoding, 'TOOLS.ENCODE') if (not charsets) or "*" in charsets or encoding in charsets: if self.debug: cherrypy.log('Attempting encoding %r' % encoding, 'TOOLS.ENCODE') if encoder(encoding): return encoding else: if not encs: if self.debug: cherrypy.log('Attempting default encoding %r' % self.default_encoding, 'TOOLS.ENCODE') # Any character-set is acceptable. if encoder(self.default_encoding): return self.default_encoding else: raise cherrypy.HTTPError(500, self.failmsg % self.default_encoding) else: for element in encs: if element.qvalue > 0: if element.value == "*": # Matches any charset. Try our default. if self.debug: cherrypy.log('Attempting default encoding due ' 'to %r' % element, 'TOOLS.ENCODE') if encoder(self.default_encoding): return self.default_encoding else: encoding = element.value if self.debug: cherrypy.log('Attempting encoding %s (qvalue >' '0)' % element, 'TOOLS.ENCODE') if encoder(encoding): return encoding if "*" not in charsets: # If no "*" is present in an Accept-Charset field, then all # character sets not explicitly mentioned get a quality # value of 0, except for ISO-8859-1, which gets a quality # value of 1 if not explicitly mentioned. iso = 'iso-8859-1' if iso not in charsets: if self.debug: cherrypy.log('Attempting ISO-8859-1 encoding', 'TOOLS.ENCODE') if encoder(iso): return iso # No suitable encoding found. ac = request.headers.get('Accept-Charset') if ac is None: msg = "Your client did not send an Accept-Charset header." else: msg = "Your client sent this Accept-Charset header: %s." % ac msg += " We tried these charsets: %s." % ", ".join(self.attempted_charsets) raise cherrypy.HTTPError(406, msg) def __call__(self, *args, **kwargs): response = cherrypy.serving.response self.body = self.oldhandler(*args, **kwargs) if isinstance(self.body, basestring): # strings get wrapped in a list because iterating over a single # item list is much faster than iterating over every character # in a long string. if self.body: self.body = [self.body] else: # [''] doesn't evaluate to False, so replace it with []. self.body = [] elif hasattr(self.body, 'read'): self.body = file_generator(self.body) elif self.body is None: self.body = [] ct = response.headers.elements("Content-Type") if self.debug: cherrypy.log('Content-Type: %r' % [str(h) for h in ct], 'TOOLS.ENCODE') if ct: ct = ct[0] if self.text_only: if ct.value.lower().startswith("text/"): if self.debug: cherrypy.log('Content-Type %s starts with "text/"' % ct, 'TOOLS.ENCODE') do_find = True else: if self.debug: cherrypy.log('Not finding because Content-Type %s does ' 'not start with "text/"' % ct, 'TOOLS.ENCODE') do_find = False else: if self.debug: cherrypy.log('Finding because not text_only', 'TOOLS.ENCODE') do_find = True if do_find: # Set "charset=..." param on response Content-Type header ct.params['charset'] = self.find_acceptable_charset() if self.add_charset: if self.debug: cherrypy.log('Setting Content-Type %s' % ct, 'TOOLS.ENCODE') response.headers["Content-Type"] = str(ct) return self.body # GZIP def compress(body, compress_level): """Compress 'body' at the given compress_level.""" import zlib # See http://www.gzip.org/zlib/rfc-gzip.html yield ntob('\x1f\x8b') # ID1 and ID2: gzip marker yield ntob('\x08') # CM: compression method yield ntob('\x00') # FLG: none set # MTIME: 4 bytes yield struct.pack(" 0 is present * The 'identity' value is given with a qvalue > 0. """ request = cherrypy.serving.request response = cherrypy.serving.response set_vary_header(response, "Accept-Encoding") if not response.body: # Response body is empty (might be a 304 for instance) if debug: cherrypy.log('No response body', context='TOOLS.GZIP') return # If returning cached content (which should already have been gzipped), # don't re-zip. if getattr(request, "cached", False): if debug: cherrypy.log('Not gzipping cached response', context='TOOLS.GZIP') return acceptable = request.headers.elements('Accept-Encoding') if not acceptable: # If no Accept-Encoding field is present in a request, # the server MAY assume that the client will accept any # content coding. In this case, if "identity" is one of # the available content-codings, then the server SHOULD use # the "identity" content-coding, unless it has additional # information that a different content-coding is meaningful # to the client. if debug: cherrypy.log('No Accept-Encoding', context='TOOLS.GZIP') return ct = response.headers.get('Content-Type', '').split(';')[0] for coding in acceptable: if coding.value == 'identity' and coding.qvalue != 0: if debug: cherrypy.log('Non-zero identity qvalue: %s' % coding, context='TOOLS.GZIP') return if coding.value in ('gzip', 'x-gzip'): if coding.qvalue == 0: if debug: cherrypy.log('Zero gzip qvalue: %s' % coding, context='TOOLS.GZIP') return if ct not in mime_types: # If the list of provided mime-types contains tokens # such as 'text/*' or 'application/*+xml', # we go through them and find the most appropriate one # based on the given content-type. # The pattern matching is only caring about the most # common cases, as stated above, and doesn't support # for extra parameters. found = False if '/' in ct: ct_media_type, ct_sub_type = ct.split('/') for mime_type in mime_types: if '/' in mime_type: media_type, sub_type = mime_type.split('/') if ct_media_type == media_type: if sub_type == '*': found = True break elif '+' in sub_type and '+' in ct_sub_type: ct_left, ct_right = ct_sub_type.split('+') left, right = sub_type.split('+') if left == '*' and ct_right == right: found = True break if not found: if debug: cherrypy.log('Content-Type %s not in mime_types %r' % (ct, mime_types), context='TOOLS.GZIP') return if debug: cherrypy.log('Gzipping', context='TOOLS.GZIP') # Return a generator that compresses the page response.headers['Content-Encoding'] = 'gzip' response.body = compress(response.body, compress_level) if "Content-Length" in response.headers: # Delete Content-Length header so finalize() recalcs it. del response.headers["Content-Length"] return if debug: cherrypy.log('No acceptable encoding found.', context='GZIP') cherrypy.HTTPError(406, "identity, gzip").set_response()