Issue #12319: Support for chunked encoding of HTTP request bodies

When the body object is a file, its size is no longer determined with
fstat(), since that can report the wrong result (e.g. reading from a pipe).
Instead, determine the size using seek(), or fall back to chunked encoding
for unseekable files.

Also, change the logic for detecting text files to check for TextIOBase
inheritance, rather than inspecting the “mode” attribute, which may not
exist (e.g. BytesIO and StringIO).  The Content-Length for text files is no
longer determined ahead of time, because the original logic could have been
wrong depending on the codec and newline translation settings.

Patch by Demian Brecht and Rolf Krahl, with a few tweaks by me.
This commit is contained in:
Martin Panter 2016-08-24 06:33:33 +00:00
parent a790fe7ff8
commit 3c0d0baf2b
9 changed files with 531 additions and 150 deletions

View file

@ -795,6 +795,58 @@ class HTTPConnection:
auto_open = 1
debuglevel = 0
@staticmethod
def _is_textIO(stream):
"""Test whether a file-like object is a text or a binary stream.
"""
return isinstance(stream, io.TextIOBase)
@staticmethod
def _get_content_length(body, method):
"""Get the content-length based on the body.
If the body is "empty", we set Content-Length: 0 for methods
that expect a body (RFC 7230, Section 3.3.2). If the body is
set for other methods, we set the header provided we can
figure out what the length is.
"""
if not body:
# do an explicit check for not None here to distinguish
# between unset and set but empty
if method.upper() in _METHODS_EXPECTING_BODY or body is not None:
return 0
else:
return None
if hasattr(body, 'read'):
# file-like object.
if HTTPConnection._is_textIO(body):
# text streams are unpredictable because it depends on
# character encoding and line ending translation.
return None
else:
# Is it seekable?
try:
curpos = body.tell()
sz = body.seek(0, io.SEEK_END)
except (TypeError, AttributeError, OSError):
return None
else:
body.seek(curpos)
return sz - curpos
try:
# does it implement the buffer protocol (bytes, bytearray, array)?
mv = memoryview(body)
return mv.nbytes
except TypeError:
pass
if isinstance(body, str):
return len(body)
return None
def __init__(self, host, port=None, timeout=socket._GLOBAL_DEFAULT_TIMEOUT,
source_address=None):
self.timeout = timeout
@ -933,18 +985,9 @@ class HTTPConnection:
if hasattr(data, "read") :
if self.debuglevel > 0:
print("sendIng a read()able")
encode = False
try:
mode = data.mode
except AttributeError:
# io.BytesIO and other file-like objects don't have a `mode`
# attribute.
pass
else:
if "b" not in mode:
encode = True
if self.debuglevel > 0:
print("encoding file using iso-8859-1")
encode = self._is_textIO(data)
if encode and self.debuglevel > 0:
print("encoding file using iso-8859-1")
while 1:
datablock = data.read(blocksize)
if not datablock:
@ -970,7 +1013,22 @@ class HTTPConnection:
"""
self._buffer.append(s)
def _send_output(self, message_body=None):
def _read_readable(self, readable):
blocksize = 8192
if self.debuglevel > 0:
print("sendIng a read()able")
encode = self._is_textIO(readable)
if encode and self.debuglevel > 0:
print("encoding file using iso-8859-1")
while True:
datablock = readable.read(blocksize)
if not datablock:
break
if encode:
datablock = datablock.encode("iso-8859-1")
yield datablock
def _send_output(self, message_body=None, encode_chunked=False):
"""Send the currently buffered request and clear the buffer.
Appends an extra \\r\\n to the buffer.
@ -979,10 +1037,50 @@ class HTTPConnection:
self._buffer.extend((b"", b""))
msg = b"\r\n".join(self._buffer)
del self._buffer[:]
self.send(msg)
if message_body is not None:
self.send(message_body)
# create a consistent interface to message_body
if hasattr(message_body, 'read'):
# Let file-like take precedence over byte-like. This
# is needed to allow the current position of mmap'ed
# files to be taken into account.
chunks = self._read_readable(message_body)
else:
try:
# this is solely to check to see if message_body
# implements the buffer API. it /would/ be easier
# to capture if PyObject_CheckBuffer was exposed
# to Python.
memoryview(message_body)
except TypeError:
try:
chunks = iter(message_body)
except TypeError:
raise TypeError("message_body should be a bytes-like "
"object or an iterable, got %r"
% type(message_body))
else:
# the object implements the buffer interface and
# can be passed directly into socket methods
chunks = (message_body,)
for chunk in chunks:
if not chunk:
if self.debuglevel > 0:
print('Zero length chunk ignored')
continue
if encode_chunked and self._http_vsn == 11:
# chunked encoding
chunk = f'{len(chunk):X}\r\n'.encode('ascii') + chunk \
+ b'\r\n'
self.send(chunk)
if encode_chunked and self._http_vsn == 11:
# end chunked transfer
self.send(b'0\r\n\r\n')
def putrequest(self, method, url, skip_host=0, skip_accept_encoding=0):
"""Send a request to the server.
@ -1135,52 +1233,27 @@ class HTTPConnection:
header = header + b': ' + value
self._output(header)
def endheaders(self, message_body=None):
def endheaders(self, message_body=None, *, encode_chunked=False):
"""Indicate that the last header line has been sent to the server.
This method sends the request to the server. The optional message_body
argument can be used to pass a message body associated with the
request. The message body will be sent in the same packet as the
message headers if it is a string, otherwise it is sent as a separate
packet.
request.
"""
if self.__state == _CS_REQ_STARTED:
self.__state = _CS_REQ_SENT
else:
raise CannotSendHeader()
self._send_output(message_body)
self._send_output(message_body, encode_chunked=encode_chunked)
def request(self, method, url, body=None, headers={}):
def request(self, method, url, body=None, headers={}, *,
encode_chunked=False):
"""Send a complete request to the server."""
self._send_request(method, url, body, headers)
self._send_request(method, url, body, headers, encode_chunked)
def _set_content_length(self, body, method):
# Set the content-length based on the body. If the body is "empty", we
# set Content-Length: 0 for methods that expect a body (RFC 7230,
# Section 3.3.2). If the body is set for other methods, we set the
# header provided we can figure out what the length is.
thelen = None
method_expects_body = method.upper() in _METHODS_EXPECTING_BODY
if body is None and method_expects_body:
thelen = '0'
elif body is not None:
try:
thelen = str(len(body))
except TypeError:
# If this is a file-like object, try to
# fstat its file descriptor
try:
thelen = str(os.fstat(body.fileno()).st_size)
except (AttributeError, OSError):
# Don't send a length if this failed
if self.debuglevel > 0: print("Cannot stat!!")
if thelen is not None:
self.putheader('Content-Length', thelen)
def _send_request(self, method, url, body, headers):
def _send_request(self, method, url, body, headers, encode_chunked):
# Honor explicitly requested Host: and Accept-Encoding: headers.
header_names = dict.fromkeys([k.lower() for k in headers])
header_names = frozenset(k.lower() for k in headers)
skips = {}
if 'host' in header_names:
skips['skip_host'] = 1
@ -1189,15 +1262,41 @@ class HTTPConnection:
self.putrequest(method, url, **skips)
# chunked encoding will happen if HTTP/1.1 is used and either
# the caller passes encode_chunked=True or the following
# conditions hold:
# 1. content-length has not been explicitly set
# 2. the length of the body cannot be determined
# (e.g. it is a generator or unseekable file)
# 3. Transfer-Encoding has NOT been explicitly set by the caller
if 'content-length' not in header_names:
self._set_content_length(body, method)
# only chunk body if not explicitly set for backwards
# compatibility, assuming the client code is already handling the
# chunking
if 'transfer-encoding' not in header_names:
# if content-length cannot be automatically determined, fall
# back to chunked encoding
encode_chunked = False
content_length = self._get_content_length(body, method)
if content_length is None:
if body:
if self.debuglevel > 0:
print('Unable to determine size of %r' % body)
encode_chunked = True
self.putheader('Transfer-Encoding', 'chunked')
else:
self.putheader('Content-Length', str(content_length))
else:
encode_chunked = False
for hdr, value in headers.items():
self.putheader(hdr, value)
if isinstance(body, str):
# RFC 2616 Section 3.7.1 says that text default has a
# default charset of iso-8859-1.
body = _encode(body, 'body')
self.endheaders(body)
self.endheaders(body, encode_chunked=encode_chunked)
def getresponse(self):
"""Get the response from the server.