Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 1 | .. currentmodule:: asyncio |
| 2 | |
Victor Stinner | 9592edb | 2014-02-02 15:03:02 +0100 | [diff] [blame] | 3 | .. _asyncio-streams: |
Victor Stinner | 4b4f9eb | 2014-01-24 17:33:20 +0100 | [diff] [blame] | 4 | |
Victor Stinner | 1374bd4 | 2014-01-24 15:34:19 +0100 | [diff] [blame] | 5 | ++++++++++++++++++++++++ |
| 6 | Streams (high-level API) |
| 7 | ++++++++++++++++++++++++ |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 8 | |
| 9 | Stream functions |
| 10 | ================ |
| 11 | |
Guido van Rossum | 19ff697 | 2015-10-19 13:18:04 -0700 | [diff] [blame] | 12 | .. note:: |
| 13 | |
| 14 | The top-level functions in this module are meant convenience wrappers |
| 15 | only; there's really nothing special there, and if they don't do |
| 16 | exactly what you want, feel free to copy their code. |
| 17 | |
| 18 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 19 | .. coroutinefunction:: open_connection(host=None, port=None, \*, loop=None, limit=None, \*\*kwds) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 20 | |
| 21 | A wrapper for :meth:`~BaseEventLoop.create_connection()` returning a (reader, |
| 22 | writer) pair. |
| 23 | |
| 24 | The reader returned is a :class:`StreamReader` instance; the writer is |
| 25 | a :class:`StreamWriter` instance. |
| 26 | |
| 27 | The arguments are all the usual arguments to |
| 28 | :meth:`BaseEventLoop.create_connection` except *protocol_factory*; most |
| 29 | common are positional host and port, with various optional keyword arguments |
| 30 | following. |
| 31 | |
| 32 | Additional optional keyword arguments are *loop* (to set the event loop |
| 33 | instance to use) and *limit* (to set the buffer limit passed to the |
| 34 | :class:`StreamReader`). |
| 35 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 36 | This function is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 37 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 38 | .. coroutinefunction:: start_server(client_connected_cb, host=None, port=None, \*, loop=None, limit=None, \*\*kwds) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 39 | |
Victor Stinner | 8ebeb03 | 2014-07-11 23:47:40 +0200 | [diff] [blame] | 40 | Start a socket server, with a callback for each client connected. The return |
| 41 | value is the same as :meth:`~BaseEventLoop.create_server()`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 42 | |
Victor Stinner | 8ebeb03 | 2014-07-11 23:47:40 +0200 | [diff] [blame] | 43 | The *client_connected_cb* parameter is called with two parameters: |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 44 | *client_reader*, *client_writer*. *client_reader* is a |
| 45 | :class:`StreamReader` object, while *client_writer* is a |
Victor Stinner | 8ebeb03 | 2014-07-11 23:47:40 +0200 | [diff] [blame] | 46 | :class:`StreamWriter` object. The *client_connected_cb* parameter can |
| 47 | either be a plain callback function or a :ref:`coroutine function |
| 48 | <coroutine>`; if it is a coroutine function, it will be automatically |
Victor Stinner | 337e03f | 2014-08-11 01:11:13 +0200 | [diff] [blame] | 49 | converted into a :class:`Task`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 50 | |
| 51 | The rest of the arguments are all the usual arguments to |
| 52 | :meth:`~BaseEventLoop.create_server()` except *protocol_factory*; most |
Victor Stinner | 8ebeb03 | 2014-07-11 23:47:40 +0200 | [diff] [blame] | 53 | common are positional *host* and *port*, with various optional keyword |
| 54 | arguments following. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 55 | |
| 56 | Additional optional keyword arguments are *loop* (to set the event loop |
| 57 | instance to use) and *limit* (to set the buffer limit passed to the |
| 58 | :class:`StreamReader`). |
| 59 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 60 | This function is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 61 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 62 | .. coroutinefunction:: open_unix_connection(path=None, \*, loop=None, limit=None, **kwds) |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 63 | |
| 64 | A wrapper for :meth:`~BaseEventLoop.create_unix_connection()` returning |
| 65 | a (reader, writer) pair. |
| 66 | |
| 67 | See :func:`open_connection` for information about return value and other |
| 68 | details. |
| 69 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 70 | This function is a :ref:`coroutine <coroutine>`. |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 71 | |
| 72 | Availability: UNIX. |
| 73 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 74 | .. coroutinefunction:: start_unix_server(client_connected_cb, path=None, \*, loop=None, limit=None, **kwds) |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 75 | |
| 76 | Start a UNIX Domain Socket server, with a callback for each client connected. |
| 77 | |
| 78 | See :func:`start_server` for information about return value and other |
| 79 | details. |
| 80 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 81 | This function is a :ref:`coroutine <coroutine>`. |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 82 | |
| 83 | Availability: UNIX. |
| 84 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 85 | |
| 86 | StreamReader |
| 87 | ============ |
| 88 | |
Victor Stinner | 0844438 | 2014-02-02 22:43:39 +0100 | [diff] [blame] | 89 | .. class:: StreamReader(limit=None, loop=None) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 90 | |
Victor Stinner | 8370496 | 2015-02-25 14:24:15 +0100 | [diff] [blame] | 91 | This class is :ref:`not thread safe <asyncio-multithreading>`. |
| 92 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 93 | .. method:: exception() |
| 94 | |
| 95 | Get the exception. |
| 96 | |
| 97 | .. method:: feed_eof() |
| 98 | |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 99 | Acknowledge the EOF. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 100 | |
| 101 | .. method:: feed_data(data) |
| 102 | |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 103 | Feed *data* bytes in the internal buffer. Any operations waiting |
| 104 | for the data will be resumed. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 105 | |
| 106 | .. method:: set_exception(exc) |
| 107 | |
| 108 | Set the exception. |
| 109 | |
| 110 | .. method:: set_transport(transport) |
| 111 | |
| 112 | Set the transport. |
| 113 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 114 | .. coroutinemethod:: read(n=-1) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 115 | |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 116 | Read up to *n* bytes. If *n* is not provided, or set to ``-1``, |
| 117 | read until EOF and return all read bytes. |
| 118 | |
| 119 | If the EOF was received and the internal buffer is empty, |
| 120 | return an empty ``bytes`` object. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 121 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 122 | This method is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 123 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 124 | .. coroutinemethod:: readline() |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 125 | |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 126 | Read one line, where "line" is a sequence of bytes ending with ``\n``. |
| 127 | |
| 128 | If EOF is received, and ``\n`` was not found, the method will |
| 129 | return the partial read bytes. |
| 130 | |
| 131 | If the EOF was received and the internal buffer is empty, |
| 132 | return an empty ``bytes`` object. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 133 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 134 | This method is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 135 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 136 | .. coroutinemethod:: readexactly(n) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 137 | |
Victor Stinner | b7f19ff | 2014-01-27 11:58:49 +0100 | [diff] [blame] | 138 | Read exactly *n* bytes. Raise an :exc:`IncompleteReadError` if the end of |
| 139 | the stream is reached before *n* can be read, the |
| 140 | :attr:`IncompleteReadError.partial` attribute of the exception contains |
| 141 | the partial read bytes. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 142 | |
Yury Selivanov | 37f15bc | 2014-02-20 16:20:44 -0500 | [diff] [blame] | 143 | This method is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 144 | |
Yury Selivanov | d3f8e30 | 2014-02-20 14:10:02 -0500 | [diff] [blame] | 145 | .. method:: at_eof() |
| 146 | |
| 147 | Return ``True`` if the buffer is empty and :meth:`feed_eof` was called. |
| 148 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 149 | |
| 150 | StreamWriter |
| 151 | ============ |
| 152 | |
| 153 | .. class:: StreamWriter(transport, protocol, reader, loop) |
| 154 | |
| 155 | Wraps a Transport. |
| 156 | |
| 157 | This exposes :meth:`write`, :meth:`writelines`, :meth:`can_write_eof()`, |
| 158 | :meth:`write_eof`, :meth:`get_extra_info` and :meth:`close`. It adds |
| 159 | :meth:`drain` which returns an optional :class:`Future` on which you can |
| 160 | wait for flow control. It also adds a transport attribute which references |
| 161 | the :class:`Transport` directly. |
| 162 | |
Victor Stinner | 8370496 | 2015-02-25 14:24:15 +0100 | [diff] [blame] | 163 | This class is :ref:`not thread safe <asyncio-multithreading>`. |
| 164 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 165 | .. attribute:: transport |
| 166 | |
| 167 | Transport. |
| 168 | |
Victor Stinner | ffbe3c6 | 2014-02-08 22:50:07 +0100 | [diff] [blame] | 169 | .. method:: can_write_eof() |
| 170 | |
| 171 | Return :const:`True` if the transport supports :meth:`write_eof`, |
| 172 | :const:`False` if not. See :meth:`WriteTransport.can_write_eof`. |
| 173 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 174 | .. method:: close() |
| 175 | |
| 176 | Close the transport: see :meth:`BaseTransport.close`. |
| 177 | |
Victor Stinner | bdd574d | 2015-02-12 22:49:18 +0100 | [diff] [blame] | 178 | .. coroutinemethod:: drain() |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 179 | |
Victor Stinner | e718297 | 2014-11-28 17:45:41 +0100 | [diff] [blame] | 180 | Let the write buffer of the underlying transport a chance to be flushed. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 181 | |
Victor Stinner | d71dcbb | 2014-08-25 17:04:12 +0200 | [diff] [blame] | 182 | The intended use is to write:: |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 183 | |
| 184 | w.write(data) |
| 185 | yield from w.drain() |
| 186 | |
Victor Stinner | e718297 | 2014-11-28 17:45:41 +0100 | [diff] [blame] | 187 | When the size of the transport buffer reaches the high-water limit (the |
| 188 | protocol is paused), block until the size of the buffer is drained down |
| 189 | to the low-water limit and the protocol is resumed. When there is nothing |
| 190 | to wait for, the yield-from continues immediately. |
| 191 | |
| 192 | Yielding from :meth:`drain` gives the opportunity for the loop to |
| 193 | schedule the write operation and flush the buffer. It should especially |
| 194 | be used when a possibly large amount of data is written to the transport, |
| 195 | and the coroutine does not yield-from between calls to :meth:`write`. |
Victor Stinner | d71dcbb | 2014-08-25 17:04:12 +0200 | [diff] [blame] | 196 | |
| 197 | This method is a :ref:`coroutine <coroutine>`. |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 198 | |
| 199 | .. method:: get_extra_info(name, default=None) |
| 200 | |
| 201 | Return optional transport information: see |
| 202 | :meth:`BaseTransport.get_extra_info`. |
| 203 | |
| 204 | .. method:: write(data) |
| 205 | |
| 206 | Write some *data* bytes to the transport: see |
| 207 | :meth:`WriteTransport.write`. |
| 208 | |
| 209 | .. method:: writelines(data) |
| 210 | |
| 211 | Write a list (or any iterable) of data bytes to the transport: |
| 212 | see :meth:`WriteTransport.writelines`. |
| 213 | |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 214 | .. method:: write_eof() |
| 215 | |
| 216 | Close the write end of the transport after flushing buffered data: |
| 217 | see :meth:`WriteTransport.write_eof`. |
| 218 | |
| 219 | |
| 220 | StreamReaderProtocol |
| 221 | ==================== |
| 222 | |
| 223 | .. class:: StreamReaderProtocol(stream_reader, client_connected_cb=None, loop=None) |
| 224 | |
| 225 | Trivial helper class to adapt between :class:`Protocol` and |
| 226 | :class:`StreamReader`. Sublclass of :class:`Protocol`. |
| 227 | |
| 228 | *stream_reader* is a :class:`StreamReader` instance, *client_connected_cb* |
| 229 | is an optional function called with (stream_reader, stream_writer) when a |
| 230 | connection is made, *loop* is the event loop instance to use. |
| 231 | |
| 232 | (This is a helper class instead of making :class:`StreamReader` itself a |
| 233 | :class:`Protocol` subclass, because the :class:`StreamReader` has other |
R David Murray | 87d0066 | 2015-09-27 12:36:19 -0400 | [diff] [blame] | 234 | potential uses, and to prevent the user of the :class:`StreamReader` from |
| 235 | accidentally calling inappropriate methods of the protocol.) |
Victor Stinner | 24f8ebf | 2014-01-23 11:05:01 +0100 | [diff] [blame] | 236 | |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 237 | |
Victor Stinner | b7f19ff | 2014-01-27 11:58:49 +0100 | [diff] [blame] | 238 | IncompleteReadError |
| 239 | =================== |
| 240 | |
| 241 | .. exception:: IncompleteReadError |
| 242 | |
Victor Stinner | 32970b8 | 2014-01-27 12:18:49 +0100 | [diff] [blame] | 243 | Incomplete read error, subclass of :exc:`EOFError`. |
Victor Stinner | b7f19ff | 2014-01-27 11:58:49 +0100 | [diff] [blame] | 244 | |
| 245 | .. attribute:: expected |
| 246 | |
| 247 | Total number of expected bytes (:class:`int`). |
| 248 | |
| 249 | .. attribute:: partial |
| 250 | |
| 251 | Read bytes string before the end of stream was reached (:class:`bytes`). |
| 252 | |
| 253 | |
Victor Stinner | 5121a9b | 2014-10-11 15:52:14 +0200 | [diff] [blame] | 254 | Stream examples |
| 255 | =============== |
| 256 | |
Victor Stinner | ed05159 | 2014-10-12 20:18:16 +0200 | [diff] [blame] | 257 | .. _asyncio-tcp-echo-client-streams: |
| 258 | |
| 259 | TCP echo client using streams |
| 260 | ----------------------------- |
| 261 | |
| 262 | TCP echo client using the :func:`asyncio.open_connection` function:: |
| 263 | |
| 264 | import asyncio |
| 265 | |
Victor Stinner | ed8e3a9 | 2014-10-13 00:55:50 +0200 | [diff] [blame] | 266 | @asyncio.coroutine |
Victor Stinner | ed05159 | 2014-10-12 20:18:16 +0200 | [diff] [blame] | 267 | def tcp_echo_client(message, loop): |
| 268 | reader, writer = yield from asyncio.open_connection('127.0.0.1', 8888, |
| 269 | loop=loop) |
| 270 | |
| 271 | print('Send: %r' % message) |
| 272 | writer.write(message.encode()) |
| 273 | |
| 274 | data = yield from reader.read(100) |
| 275 | print('Received: %r' % data.decode()) |
| 276 | |
| 277 | print('Close the socket') |
| 278 | writer.close() |
| 279 | |
| 280 | message = 'Hello World!' |
| 281 | loop = asyncio.get_event_loop() |
| 282 | loop.run_until_complete(tcp_echo_client(message, loop)) |
| 283 | loop.close() |
| 284 | |
| 285 | .. seealso:: |
| 286 | |
| 287 | The :ref:`TCP echo client protocol <asyncio-tcp-echo-client-protocol>` |
| 288 | example uses the :meth:`BaseEventLoop.create_connection` method. |
| 289 | |
| 290 | |
| 291 | .. _asyncio-tcp-echo-server-streams: |
| 292 | |
| 293 | TCP echo server using streams |
| 294 | ----------------------------- |
| 295 | |
| 296 | TCP echo server using the :func:`asyncio.start_server` function:: |
| 297 | |
| 298 | import asyncio |
| 299 | |
| 300 | @asyncio.coroutine |
| 301 | def handle_echo(reader, writer): |
| 302 | data = yield from reader.read(100) |
| 303 | message = data.decode() |
| 304 | addr = writer.get_extra_info('peername') |
| 305 | print("Received %r from %r" % (message, addr)) |
| 306 | |
| 307 | print("Send: %r" % message) |
| 308 | writer.write(data) |
| 309 | yield from writer.drain() |
| 310 | |
| 311 | print("Close the client socket") |
| 312 | writer.close() |
| 313 | |
| 314 | loop = asyncio.get_event_loop() |
| 315 | coro = asyncio.start_server(handle_echo, '127.0.0.1', 8888, loop=loop) |
| 316 | server = loop.run_until_complete(coro) |
| 317 | |
Serhiy Storchaka | 0424eaf | 2015-09-12 17:45:25 +0300 | [diff] [blame] | 318 | # Serve requests until Ctrl+C is pressed |
Victor Stinner | ed05159 | 2014-10-12 20:18:16 +0200 | [diff] [blame] | 319 | print('Serving on {}'.format(server.sockets[0].getsockname())) |
| 320 | try: |
| 321 | loop.run_forever() |
| 322 | except KeyboardInterrupt: |
| 323 | pass |
| 324 | |
| 325 | # Close the server |
| 326 | server.close() |
| 327 | loop.run_until_complete(server.wait_closed()) |
| 328 | loop.close() |
| 329 | |
| 330 | .. seealso:: |
| 331 | |
| 332 | The :ref:`TCP echo server protocol <asyncio-tcp-echo-server-protocol>` |
| 333 | example uses the :meth:`BaseEventLoop.create_server` method. |
| 334 | |
| 335 | |
Victor Stinner | 5121a9b | 2014-10-11 15:52:14 +0200 | [diff] [blame] | 336 | Get HTTP headers |
| 337 | ---------------- |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 338 | |
| 339 | Simple example querying HTTP headers of the URL passed on the command line:: |
| 340 | |
| 341 | import asyncio |
| 342 | import urllib.parse |
| 343 | import sys |
| 344 | |
| 345 | @asyncio.coroutine |
| 346 | def print_http_headers(url): |
| 347 | url = urllib.parse.urlsplit(url) |
Victor Stinner | 5121a9b | 2014-10-11 15:52:14 +0200 | [diff] [blame] | 348 | if url.scheme == 'https': |
| 349 | connect = asyncio.open_connection(url.hostname, 443, ssl=True) |
| 350 | else: |
| 351 | connect = asyncio.open_connection(url.hostname, 80) |
| 352 | reader, writer = yield from connect |
| 353 | query = ('HEAD {path} HTTP/1.0\r\n' |
| 354 | 'Host: {hostname}\r\n' |
| 355 | '\r\n').format(path=url.path or '/', hostname=url.hostname) |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 356 | writer.write(query.encode('latin-1')) |
| 357 | while True: |
| 358 | line = yield from reader.readline() |
| 359 | if not line: |
| 360 | break |
| 361 | line = line.decode('latin1').rstrip() |
| 362 | if line: |
| 363 | print('HTTP header> %s' % line) |
| 364 | |
Victor Stinner | 5121a9b | 2014-10-11 15:52:14 +0200 | [diff] [blame] | 365 | # Ignore the body, close the socket |
| 366 | writer.close() |
| 367 | |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 368 | url = sys.argv[1] |
| 369 | loop = asyncio.get_event_loop() |
Yury Selivanov | d7e19bb | 2015-05-11 16:33:41 -0400 | [diff] [blame] | 370 | task = asyncio.ensure_future(print_http_headers(url)) |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 371 | loop.run_until_complete(task) |
Victor Stinner | f40c663 | 2014-01-28 23:32:40 +0100 | [diff] [blame] | 372 | loop.close() |
Victor Stinner | c520edc | 2014-01-23 11:25:48 +0100 | [diff] [blame] | 373 | |
| 374 | Usage:: |
| 375 | |
| 376 | python example.py http://example.com/path/page.html |
| 377 | |
Victor Stinner | 04e6df3 | 2014-10-11 16:16:27 +0200 | [diff] [blame] | 378 | or with HTTPS:: |
| 379 | |
| 380 | python example.py https://example.com/path/page.html |
| 381 | |
| 382 | .. _asyncio-register-socket-streams: |
| 383 | |
| 384 | Register an open socket to wait for data using streams |
| 385 | ------------------------------------------------------ |
| 386 | |
| 387 | Coroutine waiting until a socket receives data using the |
| 388 | :func:`open_connection` function:: |
| 389 | |
| 390 | import asyncio |
Victor Stinner | ccd8e34 | 2014-10-11 16:30:02 +0200 | [diff] [blame] | 391 | try: |
| 392 | from socket import socketpair |
| 393 | except ImportError: |
| 394 | from asyncio.windows_utils import socketpair |
Victor Stinner | 04e6df3 | 2014-10-11 16:16:27 +0200 | [diff] [blame] | 395 | |
Victor Stinner | ed8e3a9 | 2014-10-13 00:55:50 +0200 | [diff] [blame] | 396 | @asyncio.coroutine |
Victor Stinner | 04e6df3 | 2014-10-11 16:16:27 +0200 | [diff] [blame] | 397 | def wait_for_data(loop): |
| 398 | # Create a pair of connected sockets |
Victor Stinner | ccd8e34 | 2014-10-11 16:30:02 +0200 | [diff] [blame] | 399 | rsock, wsock = socketpair() |
Victor Stinner | 04e6df3 | 2014-10-11 16:16:27 +0200 | [diff] [blame] | 400 | |
| 401 | # Register the open socket to wait for data |
| 402 | reader, writer = yield from asyncio.open_connection(sock=rsock, loop=loop) |
| 403 | |
| 404 | # Simulate the reception of data from the network |
| 405 | loop.call_soon(wsock.send, 'abc'.encode()) |
| 406 | |
| 407 | # Wait for data |
| 408 | data = yield from reader.read(100) |
| 409 | |
| 410 | # Got data, we are done: close the socket |
| 411 | print("Received:", data.decode()) |
| 412 | writer.close() |
| 413 | |
| 414 | # Close the second socket |
| 415 | wsock.close() |
| 416 | |
| 417 | loop = asyncio.get_event_loop() |
| 418 | loop.run_until_complete(wait_for_data(loop)) |
| 419 | loop.close() |
| 420 | |
| 421 | .. seealso:: |
| 422 | |
| 423 | The :ref:`register an open socket to wait for data using a protocol |
| 424 | <asyncio-register-socket>` example uses a low-level protocol created by the |
| 425 | :meth:`BaseEventLoop.create_connection` method. |
| 426 | |
| 427 | The :ref:`watch a file descriptor for read events |
| 428 | <asyncio-watch-read-event>` example uses the low-level |
| 429 | :meth:`BaseEventLoop.add_reader` method to register the file descriptor of a |
| 430 | socket. |
| 431 | |