Add CherryPy to third_party.

third_party/cherrypy/lib/encoding.py

+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()
+