def _do_read(self, length=None, use_readline=False):
if use_readline:
reader = self.rfile.readline
else:
reader = self.rfile.read
content_length = self.content_length
if content_length is None:
# Either Content-Length or "Transfer-Encoding: chunked" must be present in a request with a body
# if it was chunked, then this function would have not been called
return b''
self._send_100_continue()
left = content_length - self.position
if length is None:
length = left
elif length > left:
length = left
if not length:
return b''
# On Python 2, self.rfile is usually socket.makefile(), which
# uses cStringIO.StringIO. If *length* is greater than the C
# sizeof(int) (typically 32 bits signed), parsing the argument to
# readline raises OverflowError. StringIO.read(), OTOH, uses
# PySize_t, typically a long (64 bits). In a bare readline()
# case, because the header lines we're trying to read with
# readline are typically expected to be small, we can correct
# that failure by simply doing a smaller call to readline and
# appending; failures in read we let propagate.
try:
read = reader(length)
except OverflowError:
if not use_readline:
# Expecting to read more than 64 bits of data. Ouch!
raise
# We could loop on calls to smaller readline(), appending them
# until we actually get a newline. For uses in this module,
# we expect the actual length to be small, but WSGI applications
# are allowed to pass in an arbitrary length. (This loop isn't optimal,
# but even client applications *probably* have short lines.)
read = b''
while len(read) < length and not read.endswith(b'\n'):
read += reader(MAX_REQUEST_LINE)
self.position += len(read)
if len(read) < length:
if (use_readline and not read.endswith(b"\n")) or not use_readline:
raise IOError("unexpected end of file while reading request at position %s" % (self.position,))
return read
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