import struct
import time
import cherrypy
def decode(encoding=None, default_encoding='utf-8'):
"""Decode cherrypy.request.params from str to unicode objects."""
if not encoding:
ct = cherrypy.request.headers.elements("Content-Type")
if ct:
ct = ct[0]
encoding = ct.params.get("charset", None)
if (not encoding) and ct.value.lower().startswith("text/"):
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7.1
# When no explicit charset parameter is provided by the
# sender, media subtypes of the "text" type are defined
# to have a default charset value of "ISO-8859-1" when
# received via HTTP.
encoding = "ISO-8859-1"
if not encoding:
encoding = default_encoding
try:
decode_params(encoding)
except UnicodeDecodeError:
# IE and Firefox don't supply a charset when submitting form
# params with a CT of application/x-www-form-urlencoded.
# So after all our guessing, it could *still* be wrong.
# Start over with ISO-8859-1, since that seems to be preferred.
decode_params("ISO-8859-1")
def decode_params(encoding):
decoded_params = {}
for key, value in cherrypy.request.params.items():
if not hasattr(value, 'file'):
# Skip the value if it is an uploaded file
if isinstance(value, list):
# value is a list: decode each element
value = [v.decode(encoding) for v in value]
elif isinstance(value, str):
# value is a regular string: decode it
value = value.decode(encoding)
decoded_params[key] = value
# Decode all or nothing, so we can try again on error.
cherrypy.request.params = decoded_params
# Encoding
def encode(encoding=None, errors='strict', text_only=True, add_charset=True):
# Guard against running twice
if getattr(cherrypy.request, "_encoding_attempted", False):
return
cherrypy.request._encoding_attempted = True
ct = cherrypy.response.headers.elements("Content-Type")
if ct:
ct = ct[0]
if (not text_only) or ct.value.lower().startswith("text/"):
# Set "charset=..." param on response Content-Type header
ct.params['charset'] = find_acceptable_charset(encoding, errors=errors)
if add_charset:
cherrypy.response.headers["Content-Type"] = str(ct)
def encode_stream(encoding, errors='strict'):
"""Encode a streaming response body.
Use a generator wrapper, and just pray it works as the stream is
being written out.
"""
def encoder(body):
for chunk in body:
if isinstance(chunk, unicode):
chunk = chunk.encode(encoding, errors)
yield chunk
cherrypy.response.body = encoder(cherrypy.response.body)
return True
def encode_string(encoding, errors='strict'):
"""Encode a buffered response body."""
try:
body = []
for chunk in cherrypy.response.body:
if isinstance(chunk, unicode):
chunk = chunk.encode(encoding, errors)
body.append(chunk)
cherrypy.response.body = body
except (LookupError, UnicodeError):
return False
else:
return True
def find_acceptable_charset(encoding=None, default_encoding='utf-8', errors='strict'):
response = cherrypy.response
if cherrypy.response.stream:
encoder = encode_stream
else:
response.collapse_body()
encoder = encode_string
if response.headers.has_key("Content-Length"):
# 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 = cherrypy.request.headers.elements('Accept-Charset')
charsets = [enc.value.lower() for enc in encs]
attempted_charsets = []
if encoding is not None:
# If specified, force this encoding to be used, or fail.
encoding = encoding.lower()
if (not charsets) or "*" in charsets or encoding in charsets:
if encoder(encoding, errors):
return encoding
else:
if not encs:
# Any character-set is acceptable.
if encoder(default_encoding, errors):
return default_encoding
else:
raise cherrypy.HTTPError(500, failmsg % default_encoding)
else:
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:
attempted_charsets.append(iso)
if encoder(iso, errors):
return iso
for element in encs:
if element.qvalue > 0:
if element.value == "*":
# Matches any charset. Try our default.
if default_encoding not in attempted_charsets:
attempted_charsets.append(default_encoding)
if encoder(default_encoding, errors):
return default_encoding
else:
encoding = element.value
if encoding not in attempted_charsets:
attempted_charsets.append(encoding)
if encoder(encoding, errors):
return encoding
# No suitable encoding found.
ac = cherrypy.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(attempted_charsets)
raise cherrypy.HTTPError(406, msg)
# GZIP
def compress(body, compress_level):
"""Compress 'body' at the given compress_level."""
import zlib
yield '\037\213' # magic header
yield '\010' # compression method
yield '\0'
yield struct.pack("<L", long(time.time()))
yield '\002'
yield '\377'
crc = zlib.crc32("")
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()
yield struct.pack("<l", crc)
yield struct.pack("<L", size & 0xFFFFFFFFL)
def decompress(body):
import gzip, StringIO
zbuf = StringIO.StringIO()
zbuf.write(body)
zbuf.seek(0)
zfile = gzip.GzipFile(mode='rb', fileobj=zbuf)
data = zfile.read()
zfile.close()
return data
def gzip(compress_level=9, mime_types=['text/html', 'text/plain']):
"""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.
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.
"""
response = cherrypy.response
if not response.body:
# Response body is empty (might be a 304 for instance)
return
# If returning cached content (which should already have been gzipped),
# don't re-zip.
if getattr(cherrypy.request, "cached", False):
return
acceptable = cherrypy.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.
return
ct = response.headers.get('Content-Type', '').split(';')[0]
for coding in acceptable:
if coding.value == 'identity' and coding.qvalue != 0:
return
if coding.value in ('gzip', 'x-gzip'):
if coding.qvalue == 0:
return
if ct in mime_types:
# Return a generator that compresses the page
varies = response.headers.get("Vary", "")
varies = [x.strip() for x in varies.split(",") if x.strip()]
if "Accept-Encoding" not in varies:
varies.append("Accept-Encoding")
response.headers['Vary'] = ", ".join(varies)
response.headers['Content-Encoding'] = 'gzip'
response.body = compress(response.body, compress_level)
if response.headers.has_key("Content-Length"):
# Delete Content-Length header so finalize() recalcs it.
del response.headers["Content-Length"]
return
cherrypy.HTTPError(406, "identity, gzip").set_response()
|