Python3.5有什么新变化

argparse¶

The ArgumentParser class now allows disabling

abbreviated usage of long options by setting

allow_abbrev to False. (Contributed by Jonathan Paugh,

Steven Bethard, paul j3 and Daniel Eriksson in bpo-14910.)

asyncio¶

Since the asyncio module is provisional,

all changes introduced in Python 3.5 have also been backported to Python 3.4.x.

Notable changes in the asyncio module since Python 3.4.0:

• New debugging APIs: loop.set_debug()

  and loop.get_debug() methods.

  (Contributed by Victor Stinner.)

• The proactor event loop now supports SSL.

  (Contributed by Antoine Pitrou and Victor Stinner in bpo-22560.)

• A new loop.is_closed() method to

  check if the event loop is closed.

  (Contributed by Victor Stinner in bpo-21326.)

• A new loop.create_task()

  to conveniently create and schedule a new Task

  for a coroutine. The create_task method is also used by all

  asyncio functions that wrap coroutines into tasks, such as

  asyncio.wait(), asyncio.gather(), etc.

  (Contributed by Victor Stinner.)

• A new transport.get_write_buffer_limits()

  method to inquire for high- and low- water limits of the flow

  control.

  (Contributed by Victor Stinner.)

• The async() function is deprecated in favor of

  ensure_future().

  (Contributed by Yury Selivanov.)

• New loop.set_task_factory() and

  loop.get_task_factory()

  methods to customize the task factory that loop.create_task() method uses. (Contributed by Yury

  Selivanov.)

• New Queue.join() and

  Queue.task_done() queue methods.

  (Contributed by Victor Stinner.)

• The JoinableQueue class was removed, in favor of the

  asyncio.Queue class.

  (Contributed by Victor Stinner.)

3.5.1 中的更新：

• The ensure_future() function and all functions that

  use it, such as loop.run_until_complete(),

  now accept all kinds of awaitable objects.

  (Contributed by Yury Selivanov.)

• New run_coroutine_threadsafe() function to submit

  coroutines to event loops from other threads.

  (Contributed by Vincent Michel.)

• New Transport.is_closing()

  method to check if the transport is closing or closed.

  (Contributed by Yury Selivanov.)

• The loop.create_server()

  method can now accept a list of hosts.

  (Contributed by Yann Sionneau.)

3.5.2 中的更新：

• New loop.create_future()

  method to create Future objects. This allows alternative event

  loop implementations, such as

  uvloop, to provide a faster

  asyncio.Future implementation.

  (Contributed by Yury Selivanov.)

• New loop.get_exception_handler()

  method to get the current exception handler.

  (Contributed by Yury Selivanov.)

• New StreamReader.readuntil()

  method to read data from the stream until a separator bytes

  sequence appears.

  (Contributed by Mark Korenberg.)

• The loop.create_connection()

  and loop.create_server()

  methods are optimized to avoid calling the system getaddrinfo

  function if the address is already resolved.

  (Contributed by A. Jesse Jiryu Davis.)

• The loop.sock_connect(sock,address)

  no longer requires the address to be resolved prior to the call.

  (Contributed by A. Jesse Jiryu Davis.)

bz2¶

The BZ2Decompressor.decompress

method now accepts an optional max_length argument to limit the maximum

size of decompressed data. (Contributed by Nikolaus Rath in bpo-15955.)

cgi¶

The FieldStorage class now supports the context manager

protocol. (Contributed by Berker Peksag in bpo-20289.)

cmath¶

A new function isclose() provides a way to test for approximate

equality. (Contributed by Chris Barker and Tal Einat in bpo-24270.)

code¶

The InteractiveInterpreter.showtraceback()

method now prints the full chained traceback, just like the interactive

interpreter. (Contributed by Claudiu Popa in bpo-17442.)

collections¶

The OrderedDict class is now implemented in C, which

makes it 4 to 100 times faster. (Contributed by Eric Snow in bpo-16991.)

OrderedDict.items(),

OrderedDict.keys(),

OrderedDict.values() views now support

reversed() iteration.

(Contributed by Serhiy Storchaka in bpo-19505.)

The deque class now defines

index(), insert(), and

copy(), and supports the + and * operators.

This allows deques to be recognized as a MutableSequence

and improves their substitutability for lists.

(Contributed by Raymond Hettinger in bpo-23704.)

Docstrings produced by namedtuple() can now be updated:

Point=namedtuple('Point',['x','y'])
Point.__doc__+=': Cartesian coodinate'
Point.x.__doc__='abscissa'
Point.y.__doc__='ordinate'

（由 Berker Peksag 在 bpo-24064 中贡献。）

The UserString class now implements the

__getnewargs__(), __rmod__(), casefold(),

format_map(), isprintable(), and maketrans()

methods to match the corresponding methods of str.

(Contributed by Joe Jevnik in bpo-22189.)

collections.abc¶

The Sequence.index() method now

accepts start and stop arguments to match the corresponding methods

of tuple, list, etc.

(Contributed by Devin Jeanpierre in bpo-23086.)

A new Generator abstract base class. (Contributed

by Stefan Behnel in bpo-24018.)

New Awaitable, Coroutine,

AsyncIterator, and

AsyncIterable abstract base classes.

(Contributed by Yury Selivanov in bpo-24184.)

For earlier Python versions, a backport of the new ABCs is available in an

external PyPI package.

compileall¶

A new compileall option, -jN, allows running N workers

simultaneously to perform parallel bytecode compilation.

The compile_dir() function has a corresponding workers

parameter. (Contributed by Claudiu Popa in bpo-16104.)

Another new option, -r, allows controlling the maximum recursion

level for subdirectories. (Contributed by Claudiu Popa in bpo-19628.)

The -q command line option can now be specified more than once, in

which case all output, including errors, will be suppressed. The corresponding

quiet parameter in compile_dir(),

compile_file(), and compile_path() can now

accept an integer value indicating the level of output suppression.

(Contributed by Thomas Kluyver in bpo-21338.)

concurrent.futures¶

The Executor.map() method now accepts a

chunksize argument to allow batching of tasks to improve performance when

ProcessPoolExecutor() is used.

(Contributed by Dan O'Reilly in bpo-11271.)

The number of workers in the ThreadPoolExecutor

constructor is optional now. The default value is 5 times the number of CPUs.

(Contributed by Claudiu Popa in bpo-21527.)

configparser¶

configparser now provides a way to customize the conversion

of values by specifying a dictionary of converters in the

ConfigParser constructor, or by defining them

as methods in ConfigParser subclasses. Converters defined in

a parser instance are inherited by its section proxies.

示例:

>>> importconfigparser
>>> conv={}
>>> conv['list']=lambdav:[e.strip()foreinv.split()ife.strip()]
>>> cfg=configparser.ConfigParser(converters=conv)
>>> cfg.read_string("""
... [s]
... list = a b c d e f g
... """)
>>> cfg.get('s','list')
'a b c d e f g'
>>> cfg.getlist('s','list')
['a', 'b', 'c', 'd', 'e', 'f', 'g']
>>> section=cfg['s']
>>> section.getlist('list')
['a', 'b', 'c', 'd', 'e', 'f', 'g']

（由 Łukasz Langa 在 bpo-18159 中贡献。）

contextlib¶

The new redirect_stderr()context manager (similar to

redirect_stdout()) makes it easier for utility scripts to

handle inflexible APIs that write their output to sys.stderr and

don't provide any options to redirect it:

>>> importcontextlib,io,logging
>>> f=io.StringIO()
>>> withcontextlib.redirect_stderr(f):
... logging.warning('warning')
...
>>> f.getvalue()
'WARNING:root:warning\n'

（由 Berker Peksag 在 bpo-22389 中贡献。）

csv¶

The writerow() method now supports arbitrary iterables,

not just sequences. (Contributed by Serhiy Storchaka in bpo-23171.)

curses¶

The new update_lines_cols() function updates the LINES

and COLS environment variables. This is useful for detecting

manual screen resizing. (Contributed by Arnon Yaari in bpo-4254.)

dbm¶

dumb.open always creates a new database when the flag

has the value "n". (Contributed by Claudiu Popa in bpo-18039.)

difflib¶

The charset of HTML documents generated by

HtmlDiff.make_file()

can now be customized by using a new charset keyword-only argument.

The default charset of HTML document changed from "ISO-8859-1"

to "utf-8".

(Contributed by Berker Peksag in bpo-2052.)

The diff_bytes() function can now compare lists of byte

strings. This fixes a regression from Python 2.

(Contributed by Terry J. Reedy and Greg Ward in bpo-17445.)

distutils¶

Both the build and build_ext commands now accept a -j option to

enable parallel building of extension modules.

(Contributed by Antoine Pitrou in bpo-5309.)

The distutils module now supports xz compression, and can be

enabled by passing xztar as an argument to bdist--format.

(Contributed by Serhiy Storchaka in bpo-16314.)

doctest¶

The DocTestSuite() function returns an empty

unittest.TestSuite if module contains no docstrings, instead of

raising ValueError. (Contributed by Glenn Jones in bpo-15916.)

email¶

A new policy option Policy.mangle_from_

controls whether or not lines that start with "From" in email bodies are

prefixed with a ">" character by generators. The default is True for

compat32 and False for all other policies.

(Contributed by Milan Oberkirch in bpo-20098.)

A new

Message.get_content_disposition()

method provides easy access to a canonical value for the

Content-Disposition header.

(Contributed by Abhilash Raj in bpo-21083.)

A new policy option EmailPolicy.utf8

can be set to True to encode email headers using the UTF-8 charset instead

of using encoded words. This allows Messages to be formatted according to

RFC 6532 and used with an SMTP server that supports the RFC 6531

SMTPUTF8 extension. (Contributed by R. David Murray in

bpo-24211.)

The mime.text.MIMEText constructor now

accepts a charset.Charset instance.

(Contributed by Claude Paroz and Berker Peksag in bpo-16324.)

enum¶

The Enum callable has a new parameter start to

specify the initial number of enum values if only names are provided:

>>> Animal=enum.Enum('Animal','cat dog',start=10)
>>> Animal.cat
<Animal.cat: 10>
>>> Animal.dog
<Animal.dog: 11>

（由 Ethan Furman 在 bpo-21706 中贡献。）

faulthandler¶

The enable(), register(),

dump_traceback() and

dump_traceback_later() functions now accept file

descriptors in addition to file-like objects.

(Contributed by Wei Wu in bpo-23566.)

functools¶

Most of the lru_cache() machinery is now implemented in C, making

it significantly faster. (Contributed by Matt Joiner, Alexey Kachayev, and

Serhiy Storchaka in bpo-14373.)

glob¶

The iglob() and glob() functions now support recursive

search in subdirectories, using the "**" pattern.

(Contributed by Serhiy Storchaka in bpo-13968.)

gzip¶

The mode argument of the GzipFile constructor now

accepts "x" to request exclusive creation.

(Contributed by Tim Heaney in bpo-19222.)

heapq¶

Element comparison in merge() can now be customized by

passing a key function in a new optional key keyword argument,

and a new optional reverse keyword argument can be used to reverse element

comparison:

>>> importheapq
>>> a=['9','777','55555']
>>> b=['88','6666']
>>> list(heapq.merge(a,b,key=len))
['9', '88', '777', '6666', '55555']
>>> list(heapq.merge(reversed(a),reversed(b),key=len,reverse=True))
['55555', '6666', '777', '88', '9']

（由 Raymond Hettinger 在 bpo-13742 中贡献。）

http¶

A new HTTPStatus enum that defines a set of

HTTP status codes, reason phrases and long descriptions written in English.

(Contributed by Demian Brecht in bpo-21793.)

http.client¶

HTTPConnection.getresponse()

now raises a RemoteDisconnected exception when a

remote server connection is closed unexpectedly. Additionally, if a

ConnectionError (of which RemoteDisconnected

is a subclass) is raised, the client socket is now closed automatically,

and will reconnect on the next request:

importhttp.client
conn=http.client.HTTPConnection('www.python.org')
forretriesinrange(3):
try:
conn.request('GET','/')
resp=conn.getresponse()
excepthttp.client.RemoteDisconnected:
pass

（由 Martin Panter 在 bpo-3566 中贡献。）

idlelib 与 IDLE¶

Since idlelib implements the IDLE shell and editor and is not intended for

import by other programs, it gets improvements with every release. See

Lib/idlelib/NEWS.txt for a cumulative list of changes since 3.4.0,

as well as changes made in future 3.5.x releases. This file is also available

from the IDLE Help ‣ About IDLE dialog.

imaplib¶

The IMAP4 class now supports the context manager protocol.

When used in a with statement, the IMAP4 LOGOUT

command will be called automatically at the end of the block.

(Contributed by Tarek Ziadé and Serhiy Storchaka in bpo-4972.)

The imaplib module now supports RFC 5161 (ENABLE Extension)

and RFC 6855 (UTF-8 Support) via the IMAP4.enable()

method. A new IMAP4.utf8_enabled

attribute tracks whether or not RFC 6855 support is enabled.

(Contributed by Milan Oberkirch, R. David Murray, and Maciej Szulik in

bpo-21800.)

The imaplib module now automatically encodes non-ASCII string usernames

and passwords using UTF-8, as recommended by the RFCs. (Contributed by Milan

Oberkirch in bpo-21800.)

imghdr¶

The what() function now recognizes the

OpenEXR format

(contributed by Martin Vignali and Claudiu Popa in bpo-20295),

and the WebP format

(contributed by Fabrice Aneche and Claudiu Popa in bpo-20197.)

importlib¶

The util.LazyLoader class allows for

lazy loading of modules in applications where startup time is important.

(Contributed by Brett Cannon in bpo-17621.)

The abc.InspectLoader.source_to_code()

method is now a static method. This makes it easier to initialize a module

object with code compiled from a string by running

exec(code,module.__dict__).

(Contributed by Brett Cannon in bpo-21156.)

The new util.module_from_spec()

function is now the preferred way to create a new module. As opposed to

creating a types.ModuleType instance directly, this new function

will set the various import-controlled attributes based on the passed-in

spec object. (Contributed by Brett Cannon in bpo-20383.)

inspect¶

Both the Signature and Parameter classes are

now picklable and hashable. (Contributed by Yury Selivanov in bpo-20726

and bpo-20334.)

A new

BoundArguments.apply_defaults()

method provides a way to set default values for missing arguments:

>>> deffoo(a,b='ham',*args):pass
>>> ba=inspect.signature(foo).bind('spam')
>>> ba.apply_defaults()
>>> ba.arguments
OrderedDict([('a', 'spam'), ('b', 'ham'), ('args', ())])

（由 Yury Selivanov 在 bpo-24190 中贡献。）

A new class method

Signature.from_callable() makes

subclassing of Signature easier. (Contributed

by Yury Selivanov and Eric Snow in bpo-17373.)

The signature() function now accepts a follow_wrapped

optional keyword argument, which, when set to False, disables automatic

following of __wrapped__ links.

(Contributed by Yury Selivanov in bpo-20691.)

A set of new functions to inspect

coroutine functions and

coroutine objects has been added:

iscoroutine(), iscoroutinefunction(),

isawaitable(), getcoroutinelocals(),

and getcoroutinestate().

(Contributed by Yury Selivanov in bpo-24017 and bpo-24400.)

The stack(), trace(),

getouterframes(), and getinnerframes()

functions now return a list of named tuples.

(Contributed by Daniel Shahaf in bpo-16808.)

io¶

A new BufferedIOBase.readinto1()

method, that uses at most one call to the underlying raw stream's

RawIOBase.read() or

RawIOBase.readinto() methods.

(Contributed by Nikolaus Rath in bpo-20578.)

ipaddress¶

Both the IPv4Network and IPv6Network classes

now accept an (address,netmask) tuple argument, so as to easily construct

network objects from existing addresses:

>>> importipaddress
>>> ipaddress.IPv4Network(('127.0.0.0',8))
IPv4Network('127.0.0.0/8')
>>> ipaddress.IPv4Network(('127.0.0.0','255.0.0.0'))
IPv4Network('127.0.0.0/8')

（由 Peter Moody 和 Antoine Pitrou 在 bpo-16531 中贡献。）

A new reverse_pointer attribute for the

IPv4Network and IPv6Network classes

returns the name of the reverse DNS PTR record:

>>> importipaddress
>>> addr=ipaddress.IPv4Address('127.0.0.1')
>>> addr.reverse_pointer
'1.0.0.127.in-addr.arpa'
>>> addr6=ipaddress.IPv6Address('::1')
>>> addr6.reverse_pointer
'1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa'

（由 Leon Weber 在 bpo-20480 中贡献。）

json¶

The json.tool command line interface now preserves the order of keys in

JSON objects passed in input. The new --sort-keys option can be used

to sort the keys alphabetically. (Contributed by Berker Peksag

in bpo-21650.)

JSON decoder now raises JSONDecodeError instead of

ValueError to provide better context information about the error.

(Contributed by Serhiy Storchaka in bpo-19361.)

linecache¶

A new lazycache() function can be used to capture information

about a non-file-based module to permit getting its lines later via

getline(). This avoids doing I/O until a line is actually

needed, without having to carry the module globals around indefinitely.

(Contributed by Robert Collins in bpo-17911.)

locale¶

A new delocalize() function can be used to convert a string into

a normalized number string, taking the LC_NUMERIC settings into account:

>>> importlocale
>>> locale.setlocale(locale.LC_NUMERIC,'de_DE.UTF-8')
'de_DE.UTF-8'
>>> locale.delocalize('1.234,56')
'1234.56'
>>> locale.setlocale(locale.LC_NUMERIC,'en_US.UTF-8')
'en_US.UTF-8'
>>> locale.delocalize('1,234.56')
'1234.56'

（由 Cédric Krier 在 bpo-13918 中贡献。）

logging¶

All logging methods (Loggerlog(),

exception(), critical(),

debug(), etc.), now accept exception instances

as an exc_info argument, in addition to boolean values and exception

tuples:

>>> importlogging
>>> try:
... 1/0
... exceptZeroDivisionErrorasex:
... logging.error('exception',exc_info=ex)
ERROR:root:exception

（由 Yury Selivanov 在 bpo-20537 中贡献。）

The handlers.HTTPHandler class now

accepts an optional ssl.SSLContext instance to configure SSL

settings used in an HTTP connection.

(Contributed by Alex Gaynor in bpo-22788.)

The handlers.QueueListener class now

takes a respect_handler_level keyword argument which, if set to True,

will pass messages to handlers taking handler levels into account.

(Contributed by Vinay Sajip.)

lzma¶

The LZMADecompressor.decompress()

method now accepts an optional max_length argument to limit the maximum

size of decompressed data.

(Contributed by Martin Panter in bpo-15955.)

math¶

Two new constants have been added to the math module: inf

and nan. (Contributed by Mark Dickinson in bpo-23185.)

A new function isclose() provides a way to test for approximate

equality. (Contributed by Chris Barker and Tal Einat in bpo-24270.)

A new gcd() function has been added. The fractions.gcd()

function is now deprecated. (Contributed by Mark Dickinson and Serhiy

Storchaka in bpo-22486.)

multiprocessing¶

sharedctypes.synchronized()

objects now support the context manager protocol.

(Contributed by Charles-François Natali in bpo-21565.)

operator¶

attrgetter(), itemgetter(),

and methodcaller() objects now support pickling.

(Contributed by Josh Rosenberg and Serhiy Storchaka in bpo-22955.)

New matmul() and imatmul() functions

to perform matrix multiplication.

(Contributed by Benjamin Peterson in bpo-21176.)

os¶

The new scandir() function returning an iterator of

DirEntry objects has been added. If possible, scandir()

extracts file attributes while scanning a directory, removing the need to

perform subsequent system calls to determine file type or attributes, which may

significantly improve performance. (Contributed by Ben Hoyt with the help

of Victor Stinner in bpo-22524.)

On Windows, a new

stat_result.st_file_attributes

attribute is now available. It corresponds to the dwFileAttributes member

of the BY_HANDLE_FILE_INFORMATION structure returned by

GetFileInformationByHandle(). (Contributed by Ben Hoyt in bpo-21719.)

The urandom() function now uses the getrandom() syscall on Linux 3.17

or newer, and getentropy() on OpenBSD 5.6 and newer, removing the need to

use /dev/urandom and avoiding failures due to potential file descriptor

exhaustion. (Contributed by Victor Stinner in bpo-22181.)

New get_blocking() and set_blocking() functions allow

getting and setting a file descriptor's blocking mode (O_NONBLOCK.)

(Contributed by Victor Stinner in bpo-22054.)

The truncate() and ftruncate() functions are now supported

on Windows. (Contributed by Steve Dower in bpo-23668.)

There is a new os.path.commonpath() function returning the longest

common sub-path of each passed pathname. Unlike the

os.path.commonprefix() function, it always returns a valid

path:

>>> os.path.commonprefix(['/usr/lib','/usr/local/lib'])
'/usr/l'
>>> os.path.commonpath(['/usr/lib','/usr/local/lib'])
'/usr'

（由 Rafik Draoui 和 Serhiy Storchaka 在 bpo-10395 中贡献。）

pathlib¶

The new Path.samefile() method can be used

to check whether the path points to the same file as another path, which can

be either another Path object, or a string:

>>> importpathlib
>>> p1=pathlib.Path('/etc/hosts')
>>> p2=pathlib.Path('/etc/../etc/hosts')
>>> p1.samefile(p2)
True

（由 Vajrasky Kok 和 Antoine Pitrou 在 bpo-19775 中贡献。）

The Path.mkdir() method now accepts a new optional

exist_ok argument to match mkdir-p and os.makedirs()

functionality. (Contributed by Berker Peksag in bpo-21539.)

There is a new Path.expanduser() method to

expand ~ and ~user prefixes. (Contributed by Serhiy Storchaka and

Claudiu Popa in bpo-19776.)

A new Path.home() class method can be used to get

a Path instance representing the user’s home

directory.

(Contributed by Victor Salgado and Mayank Tripathi in bpo-19777.)

New Path.write_text(),

Path.read_text(),

Path.write_bytes(),

Path.read_bytes() methods to simplify

read/write operations on files.

The following code snippet will create or rewrite existing file

~/spam42:

>>> importpathlib
>>> p=pathlib.Path('~/spam42')
>>> p.expanduser().write_text('ham')
3

（由 Christopher Welborn 在 bpo-20218 中贡献。）

pickle¶

Nested objects, such as unbound methods or nested classes, can now be pickled

using pickle protocols older than protocol version 4.

Protocol version 4 already supports these cases. (Contributed by Serhiy

Storchaka in bpo-23611.)

poplib¶

A new POP3.utf8() command enables RFC 6856

(Internationalized Email) support, if a POP server supports it.

(Contributed by Milan OberKirch in bpo-21804.)

re¶

References and conditional references to groups with fixed length are now

allowed in lookbehind assertions:

>>> importre
>>> pat=re.compile(r'(a|b).(?<=\1)c')
>>> pat.match('aac')
<_sre.SRE_Match object; span=(0, 3), match='aac'>
>>> pat.match('bbc')
<_sre.SRE_Match object; span=(0, 3), match='bbc'>

（由 Serhiy Storchaka 在 bpo-9179 中贡献。）

The number of capturing groups in regular expressions is no longer limited to

100. (Contributed by Serhiy Storchaka in bpo-22437.)

The sub() and subn() functions now replace unmatched

groups with empty strings instead of raising an exception.

(Contributed by Serhiy Storchaka in bpo-1519638.)

The re.error exceptions have new attributes,

msg, pattern,

pos, lineno,

and colno, that provide better context

information about the error:

>>> re.compile("""
...     (?x)
...     .++
... """)
Traceback (most recent call last):
...
sre_constants.error: multiple repeat at position 16 (line 3, column 7)

（由 Serhiy Storchaka 在 bpo-22578 中贡献。）

readline¶

A new append_history_file() function can be used to append

the specified number of trailing elements in history to the given file.

(Contributed by Bruno Cauet in bpo-22940.)

selectors¶

The new DevpollSelector supports efficient

/dev/poll polling on Solaris.

(Contributed by Giampaolo Rodola' in bpo-18931.)

shutil¶

The move() function now accepts a copy_function argument,

allowing, for example, the copy() function to be used instead of

the default copy2() if there is a need to ignore file metadata

when moving.

(Contributed by Claudiu Popa in bpo-19840.)

The make_archive() function now supports the xztar format.

(Contributed by Serhiy Storchaka in bpo-5411.)

signal¶

On Windows, the set_wakeup_fd() function now also supports

socket handles. (Contributed by Victor Stinner in bpo-22018.)

Various SIG* constants in the signal module have been converted into

Enums. This allows meaningful names to be printed

during debugging, instead of integer "magic numbers".

(Contributed by Giampaolo Rodola' in bpo-21076.)

smtpd¶

Both the SMTPServer and SMTPChannel classes now

accept a decode_data keyword argument to determine if the DATA portion of

the SMTP transaction is decoded using the "utf-8" codec or is instead

provided to the

SMTPServer.process_message()

method as a byte string. The default is True for backward compatibility

reasons, but will change to False in Python 3.6. If decode_data is set

to False, the process_message method must be prepared to accept keyword

arguments.

(Contributed by Maciej Szulik in bpo-19662.)

The SMTPServer class now advertises the 8BITMIME extension

(RFC 6152) if decode_data has been set True. If the client

specifies BODY=8BITMIME on the MAIL command, it is passed to

SMTPServer.process_message()

via the mail_options keyword.

(Contributed by Milan Oberkirch and R. David Murray in bpo-21795.)

The SMTPServer class now also supports the SMTPUTF8

extension (RFC 6531: Internationalized Email). If the client specified

SMTPUTF8BODY=8BITMIME on the MAIL command, they are passed to

SMTPServer.process_message()

via the mail_options keyword. It is the responsibility of the

process_message method to correctly handle the SMTPUTF8 data.

(Contributed by Milan Oberkirch in bpo-21725.)

It is now possible to provide, directly or via name resolution, IPv6

addresses in the SMTPServer constructor, and have it

successfully connect. (Contributed by Milan Oberkirch in bpo-14758.)

smtplib¶

A new SMTP.auth() method provides a convenient way to

implement custom authentication mechanisms. (Contributed by Milan

Oberkirch in bpo-15014.)

The SMTP.set_debuglevel() method now

accepts an additional debuglevel (2), which enables timestamps in debug

messages. (Contributed by Gavin Chappell and Maciej Szulik in bpo-16914.)

Both the SMTP.sendmail() and

SMTP.send_message() methods now

support RFC 6531 (SMTPUTF8).

(Contributed by Milan Oberkirch and R. David Murray in bpo-22027.)

sndhdr¶

The what() and whathdr() functions now return

a namedtuple(). (Contributed by Claudiu Popa in

bpo-18615.)

socket¶

Functions with timeouts now use a monotonic clock, instead of a system clock.

(Contributed by Victor Stinner in bpo-22043.)

A new socket.sendfile() method allows

sending a file over a socket by using the high-performance os.sendfile()

function on UNIX, resulting in uploads being from 2 to 3 times faster than when

using plain socket.send().

(Contributed by Giampaolo Rodola' in bpo-17552.)

The socket.sendall() method no longer resets the

socket timeout every time bytes are received or sent. The socket timeout is

now the maximum total duration to send all data.

(Contributed by Victor Stinner in bpo-23853.)

The backlog argument of the socket.listen()

method is now optional. By default it is set to

SOMAXCONN or to 128, whichever is less.

(Contributed by Charles-François Natali in bpo-21455.)

ssl¶

sqlite3¶

The Row class now fully supports the sequence protocol,

in particular reversed() iteration and slice indexing.

(Contributed by Claudiu Popa in bpo-10203; by Lucas Sinclair,

Jessica McKellar, and Serhiy Storchaka in bpo-13583.)

subprocess¶

The new run() function has been added.

It runs the specified command and returns a

CompletedProcess object, which describes a finished

process. The new API is more consistent and is the recommended approach

to invoking subprocesses in Python code that does not need to maintain

compatibility with earlier Python versions.

(Contributed by Thomas Kluyver in bpo-23342.)

示例:

>>> subprocess.run(["ls","-l"])# doesn't capture output
CompletedProcess(args=['ls', '-l'], returncode=0)
>>> subprocess.run("exit 1",shell=True,check=True)
Traceback (most recent call last):
...
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1
>>> subprocess.run(["ls","-l","/dev/null"],stdout=subprocess.PIPE)
CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n')