kopia lustrzana https://github.com/micropython/micropython
251 wiersze
9.2 KiB
ReStructuredText
251 wiersze
9.2 KiB
ReStructuredText
*******************************
|
|
:mod:`usocket` -- socket module
|
|
*******************************
|
|
|
|
.. module:: usocket
|
|
:synopsis: socket module
|
|
|
|
This module provides access to the BSD socket interface.
|
|
|
|
See the corresponding `CPython module <https://docs.python.org/3/library/socket.html>`_
|
|
for comparison.
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
CPython used to have a ``socket.error`` exception which is now deprecated,
|
|
and is an alias of OSError. In MicroPython, use OSError directly.
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
For efficiency and consistency, socket objects in MicroPython implement a stream
|
|
(file-like) interface directly. In CPython, you need to convert a socket to
|
|
a file-like object using ``makefile()`` method. This method is still supported
|
|
by MicroPython (but is a no-op), so where compatibility with CPython matters,
|
|
be sure to use it.
|
|
|
|
Socket address format(s)
|
|
------------------------
|
|
|
|
The functions below which expect a network address, accept it in the format of
|
|
`(ipv4_address, port)`, where `ipv4_address` is a string with dot-notation numeric
|
|
IPv4 address, e.g. ``"8.8.8.8"``, and port is integer port number in the range
|
|
1-65535. Note the domain names are not accepted as `ipv4_address`, they should be
|
|
resolved first using ``socket.getaddrinfo()``.
|
|
|
|
Functions
|
|
---------
|
|
|
|
.. function:: socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
|
|
|
|
Create a new socket using the given address family, socket type and protocol number.
|
|
|
|
.. function:: socket.getaddrinfo(host, port)
|
|
|
|
Translate the host/port argument into a sequence of 5-tuples that contain all the
|
|
necessary arguments for creating a socket connected to that service. The list of
|
|
5-tuples has following structure::
|
|
|
|
(family, type, proto, canonname, sockaddr)
|
|
|
|
The following example shows how to connect to a given url::
|
|
|
|
s = socket.socket()
|
|
s.connect(socket.getaddrinfo('www.micropython.org', 80)[0][-1])
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
CPython raises a ``socket.gaierror`` exception (OSError subclass) in case
|
|
of error in this function. MicroPython doesn't have ``socket.gaierror``
|
|
and raises OSError directly. Note that error numbers of ``getaddrinfo()``
|
|
form a separate namespace and may not match error numbers from
|
|
``uerrno`` module. To distinguish ``getaddrinfo()`` errors, they are
|
|
represented by negative numbers, whereas standard system errors are
|
|
positive numbers (error numbers are accessible using ``e.args[0]`` property
|
|
from an exception object). The use of negative values is a provisional
|
|
detail which may change in the future.
|
|
|
|
Constants
|
|
---------
|
|
|
|
.. data:: socket.AF_INET
|
|
socket.AF_INET6
|
|
|
|
Address family types. Availability depends on a particular board.
|
|
|
|
.. data:: socket.SOCK_STREAM
|
|
socket.SOCK_DGRAM
|
|
|
|
Socket types.
|
|
|
|
.. data:: socket.IPPROTO_UDP
|
|
socket.IPPROTO_TCP
|
|
|
|
IP protocol numbers.
|
|
|
|
.. data:: socket.SOL_*
|
|
|
|
Socket option levels (an argument to ``setsockopt()``). The exact inventory depends on a board.
|
|
|
|
.. data:: socket.SO_*
|
|
|
|
Socket options (an argument to ``setsockopt()``). The exact inventory depends on a board.
|
|
|
|
Constants specific to WiPy:
|
|
|
|
.. data:: socket.IPPROTO_SEC
|
|
|
|
Special protocol value to create SSL-compatible socket.
|
|
|
|
class socket
|
|
============
|
|
|
|
Methods
|
|
-------
|
|
|
|
.. method:: socket.close
|
|
|
|
Mark the socket closed. Once that happens, all future operations on the socket
|
|
object will fail. The remote end will receive no more data (after queued data is flushed).
|
|
|
|
Sockets are automatically closed when they are garbage-collected, but it is recommended
|
|
to close() them explicitly, or to use a with statement around them.
|
|
|
|
.. method:: socket.bind(address)
|
|
|
|
Bind the socket to address. The socket must not already be bound.
|
|
|
|
.. method:: socket.listen([backlog])
|
|
|
|
Enable a server to accept connections. If backlog is specified, it must be at least 0
|
|
(if it's lower, it will be set to 0); and specifies the number of unaccepted connections
|
|
that the system will allow before refusing new connections. If not specified, a default
|
|
reasonable value is chosen.
|
|
|
|
.. method:: socket.accept()
|
|
|
|
Accept a connection. The socket must be bound to an address and listening for connections.
|
|
The return value is a pair (conn, address) where conn is a new socket object usable to send
|
|
and receive data on the connection, and address is the address bound to the socket on the
|
|
other end of the connection.
|
|
|
|
.. method:: socket.connect(address)
|
|
|
|
Connect to a remote socket at address.
|
|
|
|
.. method:: socket.send(bytes)
|
|
|
|
Send data to the socket. The socket must be connected to a remote socket.
|
|
Returns number of bytes sent, which may be smaller than the length of data
|
|
("short write").
|
|
|
|
.. method:: socket.sendall(bytes)
|
|
|
|
Send all data to the socket. The socket must be connected to a remote socket.
|
|
Unlike ``send()``, this method will try to send all of data, by sending data
|
|
chunk by chunk consecutively.
|
|
|
|
The behavior of this method on non-blocking sockets is undefined. Due to this,
|
|
on MicroPython, it's recommended to use ``write()`` method instead, which
|
|
has the same "no short writes" policy for blocking sockets, and will return
|
|
number of bytes sent on non-blocking sockets.
|
|
|
|
.. method:: socket.recv(bufsize)
|
|
|
|
Receive data from the socket. The return value is a bytes object representing the data
|
|
received. The maximum amount of data to be received at once is specified by bufsize.
|
|
|
|
.. method:: socket.sendto(bytes, address)
|
|
|
|
Send data to the socket. The socket should not be connected to a remote socket, since the
|
|
destination socket is specified by `address`.
|
|
|
|
.. method:: socket.recvfrom(bufsize)
|
|
|
|
Receive data from the socket. The return value is a pair (bytes, address) where bytes is a
|
|
bytes object representing the data received and address is the address of the socket sending
|
|
the data.
|
|
|
|
.. method:: socket.setsockopt(level, optname, value)
|
|
|
|
Set the value of the given socket option. The needed symbolic constants are defined in the
|
|
socket module (SO_* etc.). The value can be an integer or a bytes-like object representing
|
|
a buffer.
|
|
|
|
.. method:: socket.settimeout(value)
|
|
|
|
Set a timeout on blocking socket operations. The value argument can be a nonnegative floating
|
|
point number expressing seconds, or None. If a non-zero value is given, subsequent socket operations
|
|
will raise an ``OSError`` exception if the timeout period value has elapsed before the operation has
|
|
completed. If zero is given, the socket is put in non-blocking mode. If None is given, the socket
|
|
is put in blocking mode.
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
CPython raises a ``socket.timeout`` exception in case of timeout,
|
|
which is an ``OSError`` subclass. MicroPython raises an OSError directly
|
|
instead. If you use ``except OSError:`` to catch the exception,
|
|
your code will work both in MicroPython and CPython.
|
|
|
|
.. method:: socket.setblocking(flag)
|
|
|
|
Set blocking or non-blocking mode of the socket: if flag is false, the socket is set to non-blocking,
|
|
else to blocking mode.
|
|
|
|
This method is a shorthand for certain ``settimeout()`` calls:
|
|
|
|
* ``sock.setblocking(True)`` is equivalent to ``sock.settimeout(None)``
|
|
* ``sock.setblocking(False)`` is equivalent to ``sock.settimeout(0)``
|
|
|
|
.. method:: socket.makefile(mode='rb', buffering=0)
|
|
|
|
Return a file object associated with the socket. The exact returned type depends on the arguments
|
|
given to makefile(). The support is limited to binary modes only ('rb', 'wb', and 'rwb').
|
|
CPython's arguments: ``encoding``, ``errors`` and ``newline`` are not supported.
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
As MicroPython doesn't support buffered streams, values of ``buffering``
|
|
parameter is ignored and treated as if it was 0 (unbuffered).
|
|
|
|
.. admonition:: Difference to CPython
|
|
:class: attention
|
|
|
|
Closing the file object returned by makefile() WILL close the
|
|
original socket as well.
|
|
|
|
.. method:: socket.read([size])
|
|
|
|
Read up to size bytes from the socket. Return a bytes object. If ``size`` is not given, it
|
|
reads all data available from the socket until ``EOF``; as such the method will not return until
|
|
the socket is closed. This function tries to read as much data as
|
|
requested (no "short reads"). This may be not possible with
|
|
non-blocking socket though, and then less data will be returned.
|
|
|
|
.. method:: socket.readinto(buf[, nbytes])
|
|
|
|
Read bytes into the ``buf``. If ``nbytes`` is specified then read at most
|
|
that many bytes. Otherwise, read at most ``len(buf)`` bytes. Just as
|
|
``read()``, this method follows "no short reads" policy.
|
|
|
|
Return value: number of bytes read and stored into ``buf``.
|
|
|
|
.. method:: socket.readline()
|
|
|
|
Read a line, ending in a newline character.
|
|
|
|
Return value: the line read.
|
|
|
|
.. method:: socket.write(buf)
|
|
|
|
Write the buffer of bytes to the socket. This function will try to
|
|
write all data to a socket (no "short writes"). This may be not possible
|
|
with a non-blocking socket though, and returned value will be less than
|
|
the length of ``buf``.
|
|
|
|
Return value: number of bytes written.
|