18.5.5. 流 (基于协程的 API) ¶

18.5.5.1. Stream functions ¶

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.

协程 asyncio. open_connection ( host=None , port=None , * , loop=None , limit=None , **kwds ) ¶

协程 asyncio. start_server ( client_connected_cb , host=None , port=None , * , loop=None , limit=None , **kwds ) ¶

协程 asyncio. open_unix_connection ( path=None , * , loop=None , limit=None , **kwds ) ¶

协程 asyncio. start_unix_server ( client_connected_cb , path=None , * , loop=None , limit=None , **kwds ) ¶

18.5.5.2. StreamReader ¶

class asyncio. StreamReader ( limit=None , loop=None ) ¶

exception ( ) ¶

feed_eof ( ) ¶

feed_data ( data ) ¶

set_exception ( exc ) ¶

set_transport ( transport ) ¶

协程 read ( n=-1 ) ¶

协程 readline ( ) ¶

协程 readexactly ( n ) ¶

协程 readuntil ( separator=b'\n' ) ¶

at_eof ( ) ¶

18.5.5.3. StreamWriter ¶

class asyncio. StreamWriter ( transport , protocol , reader , loop ) ¶

transport ¶

can_write_eof ( ) ¶

close ( ) ¶

协程 drain ( ) ¶

get_extra_info ( name , default=None ) ¶

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() .

18.5.5.4. StreamReaderProtocol ¶

class 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.)

18.5.5.5. IncompleteReadError ¶

exception asyncio. IncompleteReadError ¶

Incomplete read error, subclass of


EOFError

expected ¶

partial ¶: Read bytes string before the end of stream was reached ( bytes ).

18.5.5.6. LimitOverrunError ¶

exception asyncio. LimitOverrunError ¶

18.5.5.7. 流范例 ¶

18.5.5.7.1. TCP echo client using streams ¶

TCP 回显客户端使用 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

The TCP 回显客户端协议范例使用 AbstractEventLoop.create_connection() 方法。

18.5.5.7.2. TCP echo server using streams ¶

TCP 回显服务器使用 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

The TCP 回显服务器协议范例使用 AbstractEventLoop.create_server() 方法。

18.5.5.7.3. Get HTTP headers ¶

查询命令行传递的 HTTP URL 头的简单范例：

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

或采用 HTTPS：

python example.py https://example.com/path/page.html

18.5.5.7.4. Register an open socket to wait for data using streams ¶

协程等待直到套接字接收数据使用 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

The 注册打开套接字等待使用协议的数据 example uses a low-level protocol created by the AbstractEventLoop.create_connection() 方法。

The 为读取事件看守文件描述符范例使用低级 AbstractEventLoop.add_reader() method to register the file descriptor of a socket.

18.5.5. 流 (基于协程的 API) ¶

18.5.5.1. Stream functions ¶

18.5.5.2. StreamReader ¶

18.5.5.3. StreamWriter ¶

18.5.5.4. StreamReaderProtocol ¶

18.5.5.5. IncompleteReadError ¶

18.5.5.6. LimitOverrunError ¶

18.5.5.7. 流范例 ¶

18.5.5.7.1. TCP echo client using streams ¶

18.5.5.7.2. TCP echo server using streams ¶

18.5.5.7.3. Get HTTP headers ¶

18.5.5.7.4. Register an open socket to wait for data using streams ¶

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