注意
The top-level functions in this module are meant as convenience wrappers only; there’s really nothing special there, and if they don’t do exactly what you want, feel free to copy their code.
asyncio.
open_connection
(
host=None
,
port=None
,
*
,
loop=None
,
limit=None
,
**kwds
)
¶
A wrapper for
create_connection()
returning a (reader, writer) pair.
The reader returned is a
StreamReader
instance; the writer is a
StreamWriter
实例。
The arguments are all the usual arguments to
AbstractEventLoop.create_connection()
except
protocol_factory
; most common are positional host and port, with various optional keyword arguments following.
Additional optional keyword arguments are
loop
(to set the event loop instance to use) and
limit
(to set the buffer limit passed to the
StreamReader
).
This function is a 协程 .
asyncio.
start_server
(
client_connected_cb
,
host=None
,
port=None
,
*
,
loop=None
,
limit=None
,
**kwds
)
¶
Start a socket server, with a callback for each client connected. The return value is the same as
create_server()
.
client_connected_cb
parameter is called with two parameters:
client_reader
,
client_writer
.
client_reader
是
StreamReader
object, while
client_writer
是
StreamWriter
object. The
client_connected_cb
parameter can either be a plain callback function or a
协程函数
; if it is a coroutine function, it will be automatically converted into a
Task
.
The rest of the arguments are all the usual arguments to
create_server()
except
protocol_factory
; most common are positional
host
and
port
, with various optional keyword arguments following.
Additional optional keyword arguments are
loop
(to set the event loop instance to use) and
limit
(to set the buffer limit passed to the
StreamReader
).
This function is a 协程 .
asyncio.
open_unix_connection
(
path=None
,
*
,
loop=None
,
limit=None
,
**kwds
)
¶
A wrapper for
create_unix_connection()
returning a (reader, writer) pair.
见
open_connection()
for information about return value and other details.
This function is a 协程 .
可用性：UNIX。
asyncio.
start_unix_server
(
client_connected_cb
,
path=None
,
*
,
loop=None
,
limit=None
,
**kwds
)
¶
Start a UNIX Domain Socket server, with a callback for each client connected.
见
start_server()
for information about return value and other details.
This function is a 协程 .
可用性：UNIX。
asyncio.
StreamReader
(
limit=_DEFAULT_LIMIT
,
loop=None
)
¶
此类是 not thread safe .
limit argument’s default value is set to _DEFAULT_LIMIT which is 2**16 (64 KiB)
exception
(
)
¶
Get the exception.
feed_eof
(
)
¶
Acknowledge the EOF.
feed_data
(
data
)
¶
Feed data bytes in the internal buffer. Any operations waiting for the data will be resumed.
set_exception
(
exc
)
¶
Set the exception.
set_transport
(
transport
)
¶
Set the transport.
read
(
n=-1
)
¶
Read up to
n
bytes. If
n
is not provided, or set to
-1
, read until EOF and return all read bytes.
If the EOF was received and the internal buffer is empty, return an empty
bytes
对象。
此方法是 协程 .
readline
(
)
¶
Read one line, where “line” is a sequence of bytes ending with
\n
.
If EOF is received, and
\n
was not found, the method will return the partial read bytes.
If the EOF was received and the internal buffer is empty, return an empty
bytes
对象。
此方法是 协程 .
readexactly
(
n
)
¶
Read exactly
n
bytes. Raise an
IncompleteReadError
if the end of the stream is reached before
n
can be read, the
IncompleteReadError.partial
attribute of the exception contains the partial read bytes.
此方法是 协程 .
readuntil
(
separator=b'\n'
)
¶
Read data from the stream until
separator
is found.
On success, the data and separator will be removed from the internal buffer (consumed). Returned data will include the separator at the end.
Configured stream limit is used to check result. Limit sets the maximal length of data that can be returned, not counting the separator.
If an EOF occurs and the complete separator is still not found, an
IncompleteReadError
exception will be raised, and the internal buffer will be reset. The
IncompleteReadError.partial
attribute may contain the separator partially.
If the data cannot be read because of over limit, a
LimitOverrunError
exception will be raised, and the data will be left in the internal buffer, so it can be read again.
3.5.2 版新增。
at_eof
(
)
¶
返回
True
if the buffer is empty and
feed_eof()
was called.
asyncio.
StreamWriter
(
transport
,
protocol
,
reader
,
loop
)
¶
Wraps a Transport.
This exposes
write()
,
writelines()
,
can_write_eof()
,
write_eof()
,
get_extra_info()
and
close()
. It adds
drain()
which returns an optional
Future
on which you can wait for flow control. It also adds a transport attribute which references the
Transport
直接。
此类是 not thread safe .
transport
¶
Transport.
can_write_eof
(
)
¶
返回
True
if the transport supports
write_eof()
,
False
if not. See
WriteTransport.can_write_eof()
.
close
(
)
¶
Close the transport: see
BaseTransport.close()
.
drain
(
)
¶
Let the write buffer of the underlying transport a chance to be flushed.
The intended use is to write:
w.write(data)
yield from w.drain()
When the size of the transport buffer reaches the high-water limit (the protocol is paused), block until the size of the buffer is drained down to the low-water limit and the protocol is resumed. When there is nothing to wait for, the yield-from continues immediately.
Yielding from
drain()
gives the opportunity for the loop to schedule the write operation and flush the buffer. It should especially be used when a possibly large amount of data is written to the transport, and the coroutine does not yield-from between calls to
write()
.
此方法是 协程 .
get_extra_info
(
name
,
default=None
)
¶
Return optional transport information: see
BaseTransport.get_extra_info()
.
write
(
data
)
¶
Write some
data
bytes to the transport: see
WriteTransport.write()
.
writelines
(
data
)
¶
Write a list (or any iterable) of data bytes to the transport: see
WriteTransport.writelines()
.
write_eof
(
)
¶
Close the write end of the transport after flushing buffered data: see
WriteTransport.write_eof()
.
asyncio.
StreamReaderProtocol
(
stream_reader
,
client_connected_cb=None
,
loop=None
)
¶
Trivial helper class to adapt between
Protocol
and
StreamReader
. Subclass of
Protocol
.
stream_reader
是
StreamReader
instance,
client_connected_cb
is an optional function called with (stream_reader, stream_writer) when a connection is made,
loop
is the event loop instance to use.
(This is a helper class instead of making
StreamReader
itself a
Protocol
subclass, because the
StreamReader
has other potential uses, and to prevent the user of the
StreamReader
from accidentally calling inappropriate methods of the protocol.)
TCP echo client using the
asyncio.open_connection()
函数：
import asyncio
@asyncio.coroutine
def tcp_echo_client(message, loop):
reader, writer = yield from asyncio.open_connection('127.0.0.1', 8888,
loop=loop)
print('Send: %r' % message)
writer.write(message.encode())
data = yield from reader.read(100)
print('Received: %r' % data.decode())
print('Close the socket')
writer.close()
message = 'Hello World!'
loop = asyncio.get_event_loop()
loop.run_until_complete(tcp_echo_client(message, loop))
loop.close()
另请参阅
TCP echo client protocol
example uses the
AbstractEventLoop.create_connection()
方法。
TCP echo server using the
asyncio.start_server()
函数：
import asyncio
@asyncio.coroutine
def handle_echo(reader, writer):
data = yield from reader.read(100)
message = data.decode()
addr = writer.get_extra_info('peername')
print("Received %r from %r" % (message, addr))
print("Send: %r" % message)
writer.write(data)
yield from writer.drain()
print("Close the client socket")
writer.close()
loop = asyncio.get_event_loop()
coro = asyncio.start_server(handle_echo, '127.0.0.1', 8888, loop=loop)
server = loop.run_until_complete(coro)
# Serve requests until Ctrl+C is pressed
print('Serving on {}'.format(server.sockets[0].getsockname()))
try:
loop.run_forever()
except KeyboardInterrupt:
pass
# Close the server
server.close()
loop.run_until_complete(server.wait_closed())
loop.close()
另请参阅
TCP echo server protocol
example uses the
AbstractEventLoop.create_server()
方法。
Simple example querying HTTP headers of the URL passed on the command line:
import asyncio
import urllib.parse
import sys
@asyncio.coroutine
def print_http_headers(url):
url = urllib.parse.urlsplit(url)
if url.scheme == 'https':
connect = asyncio.open_connection(url.hostname, 443, ssl=True)
else:
connect = asyncio.open_connection(url.hostname, 80)
reader, writer = yield from connect
query = ('HEAD {path} HTTP/1.0\r\n'
'Host: {hostname}\r\n'
'\r\n').format(path=url.path or '/', hostname=url.hostname)
writer.write(query.encode('latin-1'))
while True:
line = yield from reader.readline()
if not line:
break
line = line.decode('latin1').rstrip()
if line:
print('HTTP header> %s' % line)
# Ignore the body, close the socket
writer.close()
url = sys.argv[1]
loop = asyncio.get_event_loop()
task = asyncio.ensure_future(print_http_headers(url))
loop.run_until_complete(task)
loop.close()
用法：
python example.py http://example.com/path/page.html
or with HTTPS:
python example.py https://example.com/path/page.html
Coroutine waiting until a socket receives data using the
open_connection()
函数：
import asyncio
try:
from socket import socketpair
except ImportError:
from asyncio.windows_utils import socketpair
@asyncio.coroutine
def wait_for_data(loop):
# Create a pair of connected sockets
rsock, wsock = socketpair()
# Register the open socket to wait for data
reader, writer = yield from asyncio.open_connection(sock=rsock, loop=loop)
# Simulate the reception of data from the network
loop.call_soon(wsock.send, 'abc'.encode())
# Wait for data
data = yield from reader.read(100)
# Got data, we are done: close the socket
print("Received:", data.decode())
writer.close()
# Close the second socket
wsock.close()
loop = asyncio.get_event_loop()
loop.run_until_complete(wait_for_data(loop))
loop.close()
另请参阅
register an open socket to wait for data using a protocol
example uses a low-level protocol created by the
AbstractEventLoop.create_connection()
方法。
watch a file descriptor for read events
example uses the low-level
AbstractEventLoop.add_reader()
method to register the file descriptor of a socket.