def finish(self):
"""Implements `.HTTPConnection.finish`."""
if (self._expected_content_remaining is not None
and self._expected_content_remaining != 0
and not self.stream.closed()):
self.stream.close()
raise httputil.HTTPOutputError(
"Tried to write %d bytes less than Content-Length" %
self._expected_content_remaining)
if self._chunking_output:
if not self.stream.closed():
self._pending_write = self.stream.write(b"0\r\n\r\n")
self._pending_write.add_done_callback(self._on_write_complete)
self._write_finished = True
# If the app finished the request while we're still reading,
# divert any remaining data away from the delegate and
# close the connection when we're done sending our response.
# Closing the connection is the only way to avoid reading the
# whole input body.
if not self._read_finished:
self._disconnect_on_finish = True
# No more data is coming, so instruct TCP to send any remaining
# data immediately instead of waiting for a full packet or ack.
self.stream.set_nodelay(True)
if self._pending_write is None:
self._finish_request(None)
else:
future_add_done_callback(self._pending_write, self._finish_request)
def multi_future(children, quiet_exceptions=()):
"""Wait for multiple asynchronous futures in parallel.
This function is similar to `multi`, but does not support
`YieldPoints <YieldPoint>`.
.. versionadded:: 4.0
.. versionchanged:: 4.2
If multiple ``Futures`` fail, any exceptions after the first (which is
raised) will be logged. Added the ``quiet_exceptions``
argument to suppress this logging for selected exception types.
.. deprecated:: 4.3
Use `multi` instead.
"""
if isinstance(children, dict):
keys = list(children.keys())
children = children.values()
else:
keys = None
children = list(map(convert_yielded, children))
assert all(is_future(i) or isinstance(i, _NullFuture) for i in children)
unfinished_children = set(children)
future = _create_future()
if not children:
future_set_result_unless_cancelled(future,
{} if keys is not None else [])
def callback(f):
unfinished_children.remove(f)
if not unfinished_children:
result_list = []
for f in children:
try:
result_list.append(f.result())
except Exception as e:
if future.done():
if not isinstance(e, quiet_exceptions):
app_log.error("Multiple exceptions in yield list",
exc_info=True)
else:
future_set_exc_info(future, sys.exc_info())
if not future.done():
if keys is not None:
future_set_result_unless_cancelled(
future, dict(zip(keys, result_list)))
else:
future_set_result_unless_cancelled(future, result_list)
listening = set()
for f in children:
if f not in listening:
listening.add(f)
future_add_done_callback(f, callback)
return future
def wrapper(*args, **kwargs):
future = func(*args, **kwargs)
def final_callback(future):
if future.result() is not None:
raise ReturnValueIgnoredError(
"@gen.engine functions cannot return values: %r" %
(future.result(), ))
# The engine interface doesn't give us any way to return
# errors but to raise them into the stack context.
# Save the stack context here to use when the Future has resolved.
future_add_done_callback(future, stack_context.wrap(final_callback))
def try_connect(self, addrs):
try:
af, addr = next(addrs)
except StopIteration:
# We've reached the end of our queue, but the other queue
# might still be working. Send a final error on the future
# only when both queues are finished.
if self.remaining == 0 and not self.future.done():
self.future.set_exception(self.last_error
or IOError("connection failed"))
return
stream, future = self.connect(af, addr)
self.streams.add(stream)
future_add_done_callback(
future, functools.partial(self.on_connect_done, addrs, af, addr))
def add_future(self, future, callback):
"""Schedules a callback on the ``IOLoop`` when the given
`.Future` is finished.
The callback is invoked with one argument, the
`.Future`.
This method only accepts `.Future` objects and not other
awaitables (unlike most of Tornado where the two are
interchangeable).
"""
assert is_future(future)
callback = stack_context.wrap(callback)
future_add_done_callback(
future, lambda future: self.add_callback(callback, future))
def __init__(self, *args, **kwargs):
if args and kwargs:
raise ValueError("You must provide args or kwargs, not both")
if kwargs:
self._unfinished = dict((f, k) for (k, f) in kwargs.items())
futures = list(kwargs.values())
else:
self._unfinished = dict((f, i) for (i, f) in enumerate(args))
futures = args
self._finished = collections.deque()
self.current_index = self.current_future = None
self._running_future = None
for future in futures:
future_add_done_callback(future, self._done_callback)
def write_headers(self, start_line, headers, chunk=None, callback=None):
"""Implements `.HTTPConnection.write_headers`."""
lines = []
if self.is_client:
self._request_start_line = start_line
lines.append(
utf8('%s %s HTTP/1.1' % (start_line[0], start_line[1])))
# Client requests with a non-empty body must have either a
# Content-Length or a Transfer-Encoding.
self._chunking_output = (start_line.method
in ('POST', 'PUT', 'PATCH')
and 'Content-Length' not in headers
and 'Transfer-Encoding' not in headers)
else:
self._response_start_line = start_line
lines.append(
utf8('HTTP/1.1 %d %s' % (start_line[1], start_line[2])))
self._chunking_output = (
# TODO: should this use
# self._request_start_line.version or
# start_line.version?
self._request_start_line.version == 'HTTP/1.1' and
# 1xx, 204 and 304 responses have no body (not even a zero-length
# body), and so should not have either Content-Length or
# Transfer-Encoding headers.
start_line.code not in (204, 304)
and (start_line.code < 100 or start_line.code >= 200) and
# No need to chunk the output if a Content-Length is specified.
'Content-Length' not in headers and
# Applications are discouraged from touching Transfer-Encoding,
# but if they do, leave it alone.
'Transfer-Encoding' not in headers)
# If connection to a 1.1 client will be closed, inform client
if (self._request_start_line.version == 'HTTP/1.1'
and self._disconnect_on_finish):
headers['Connection'] = 'close'
# If a 1.0 client asked for keep-alive, add the header.
if (self._request_start_line.version == 'HTTP/1.0'
and self._request_headers.get('Connection',
'').lower() == 'keep-alive'):
headers['Connection'] = 'Keep-Alive'
if self._chunking_output:
headers['Transfer-Encoding'] = 'chunked'
if (not self.is_client and (self._request_start_line.method == 'HEAD'
or start_line.code == 304)):
self._expected_content_remaining = 0
elif 'Content-Length' in headers:
self._expected_content_remaining = int(headers['Content-Length'])
else:
self._expected_content_remaining = None
# TODO: headers are supposed to be of type str, but we still have some
# cases that let bytes slip through. Remove these native_str calls when those
# are fixed.
header_lines = (native_str(n) + ": " + native_str(v)
for n, v in headers.get_all())
if PY3:
lines.extend(l.encode('latin1') for l in header_lines)
else:
lines.extend(header_lines)
for line in lines:
if b'\n' in line:
raise ValueError('Newline in header: ' + repr(line))
future = None
if self.stream.closed():
future = self._write_future = Future()
future.set_exception(iostream.StreamClosedError())
future.exception()
else:
if callback is not None:
warnings.warn(
"callback argument is deprecated, use returned Future instead",
DeprecationWarning)
self._write_callback = stack_context.wrap(callback)
else:
future = self._write_future = Future()
data = b"\r\n".join(lines) + b"\r\n\r\n"
if chunk:
data += self._format_chunk(chunk)
self._pending_write = self.stream.write(data)
future_add_done_callback(self._pending_write,
self._on_write_complete)
return future
def timeout_callback():
if not result.done():
result.set_exception(TimeoutError("Timeout"))
# In case the wrapped future goes on to fail, log it.
future_add_done_callback(future, error_callback)
def with_timeout(timeout, future, quiet_exceptions=()):
"""Wraps a `.Future` (or other yieldable object) in a timeout.
Raises `tornado.util.TimeoutError` if the input future does not
complete before ``timeout``, which may be specified in any form
allowed by `.IOLoop.add_timeout` (i.e. a `datetime.timedelta` or
an absolute time relative to `.IOLoop.time`)
If the wrapped `.Future` fails after it has timed out, the exception
will be logged unless it is of a type contained in ``quiet_exceptions``
(which may be an exception type or a sequence of types).
Does not support `YieldPoint` subclasses.
The wrapped `.Future` is not canceled when the timeout expires,
permitting it to be reused. `asyncio.wait_for` is similar to this
function but it does cancel the wrapped `.Future` on timeout.
.. versionadded:: 4.0
.. versionchanged:: 4.1
Added the ``quiet_exceptions`` argument and the logging of unhandled
exceptions.
.. versionchanged:: 4.4
Added support for yieldable objects other than `.Future`.
"""
# TODO: allow YieldPoints in addition to other yieldables?
# Tricky to do with stack_context semantics.
#
# It's tempting to optimize this by cancelling the input future on timeout
# instead of creating a new one, but A) we can't know if we are the only
# one waiting on the input future, so cancelling it might disrupt other
# callers and B) concurrent futures can only be cancelled while they are
# in the queue, so cancellation cannot reliably bound our waiting time.
future = convert_yielded(future)
result = _create_future()
chain_future(future, result)
io_loop = IOLoop.current()
def error_callback(future):
try:
future.result()
except Exception as e:
if not isinstance(e, quiet_exceptions):
app_log.error("Exception in Future %r after timeout",
future,
exc_info=True)
def timeout_callback():
if not result.done():
result.set_exception(TimeoutError("Timeout"))
# In case the wrapped future goes on to fail, log it.
future_add_done_callback(future, error_callback)
timeout_handle = io_loop.add_timeout(timeout, timeout_callback)
if isinstance(future, Future):
# We know this future will resolve on the IOLoop, so we don't
# need the extra thread-safety of IOLoop.add_future (and we also
# don't care about StackContext here.
future_add_done_callback(
future, lambda future: io_loop.remove_timeout(timeout_handle))
else:
# concurrent.futures.Futures may resolve on any thread, so we
# need to route them back to the IOLoop.
io_loop.add_future(
future, lambda future: io_loop.remove_timeout(timeout_handle))
return result