diff options
Diffstat (limited to 'cherrypy/lib/encoding.py')
| -rwxr-xr-x | cherrypy/lib/encoding.py | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/cherrypy/lib/encoding.py b/cherrypy/lib/encoding.py new file mode 100755 index 0000000..6459746 --- /dev/null +++ b/cherrypy/lib/encoding.py @@ -0,0 +1,388 @@ +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("<L", int(time.time()) & int('FFFFFFFF', 16)) + yield ntob('\x02') # XFL: max compression, slowest algo + yield ntob('\xff') # OS: unknown + + crc = zlib.crc32(ntob("")) + size = 0 + zobj = zlib.compressobj(compress_level, + zlib.DEFLATED, -zlib.MAX_WBITS, + zlib.DEF_MEM_LEVEL, 0) + for line in body: + size += len(line) + crc = zlib.crc32(line, crc) + yield zobj.compress(line) + yield zobj.flush() + + # CRC32: 4 bytes + yield struct.pack("<L", crc & int('FFFFFFFF', 16)) + # ISIZE: 4 bytes + yield struct.pack("<L", size & int('FFFFFFFF', 16)) + +def decompress(body): + import gzip + + zbuf = BytesIO() + zbuf.write(body) + zbuf.seek(0) + zfile = gzip.GzipFile(mode='rb', fileobj=zbuf) + data = zfile.read() + zfile.close() + return data + + +def gzip(compress_level=5, mime_types=['text/html', 'text/plain'], debug=False): + """Try to gzip the response body if Content-Type in mime_types. + + cherrypy.response.headers['Content-Type'] must be set to one of the + values in the mime_types arg before calling this function. + + The provided list of mime-types must be of one of the following form: + * type/subtype + * type/* + * type/*+subtype + + No compression is performed if any of the following hold: + * The client sends no Accept-Encoding request header + * No 'gzip' or 'x-gzip' is present in the Accept-Encoding header + * No 'gzip' or 'x-gzip' with a qvalue > 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() + |