| Python 3.6.5 Documentation > "nntplib" — NNTP protocol client
"nntplib" — NNTP protocol client
********************************
**Source code:** Lib/nntplib.py
======================================================================
This module defines the class "NNTP" which implements the client side
of the Network News Transfer Protocol. It can be used to implement a
news reader or poster, or automated news processors. It is compatible
with **RFC 3977** as well as the older **RFC 977** and **RFC 2980**.
Here are two small examples of how it can be used. To list some
statistics about a newsgroup and print the subjects of the last 10
articles:
>>> s = nntplib.NNTP('news.gmane.org')
>>> resp, count, first, last, name = s.group('gmane.comp.python.committers')
>>> print('Group', name, 'has', count, 'articles, range', first, 'to', last)
Group gmane.comp.python.committers has 1096 articles, range 1 to 1096
>>> resp, overviews = s.over((last - 9, last))
>>> for id, over in overviews:
... print(id, nntplib.decode_header(over['subject']))
...
1087 Re: Commit privileges for ?ukasz Langa
1088 Re: 3.2 alpha 2 freeze
1089 Re: 3.2 alpha 2 freeze
1090 Re: Commit privileges for ?ukasz Langa
1091 Re: Commit privileges for ?ukasz Langa
1092 Updated ssh key
1093 Re: Updated ssh key
1094 Re: Updated ssh key
1095 Hello fellow committers!
1096 Re: Hello fellow committers!
>>> s.quit()
'205 Bye!'
To post an article from a binary file (this assumes that the article
has valid headers, and that you have right to post on the particular
newsgroup):
>>> s = nntplib.NNTP('news.gmane.org')
>>> f = open('article.txt', 'rb')
>>> s.post(f)
'240 Article posted successfully.'
>>> s.quit()
'205 Bye!'
The module itself defines the following classes:
class nntplib.NNTP(host, port=119, user=None, password=None, readermode=None, usenetrc=False[, timeout])
Return a new "NNTP" object, representing a connection to the NNTP
server running on host *host*, listening at port *port*. An
optional *timeout* can be specified for the socket connection. If
the optional *user* and *password* are provided, or if suitable
credentials are present in "/.netrc" and the optional flag
*usenetrc* is true, the "AUTHINFO USER" and "AUTHINFO PASS"
commands are used to identify and authenticate the user to the
server. If the optional flag *readermode* is true, then a "mode
reader" command is sent before authentication is performed. Reader
mode is sometimes necessary if you are connecting to an NNTP server
on the local machine and intend to call reader-specific commands,
such as "group". If you get unexpected "NNTPPermanentError"s, you
might need to set *readermode*. The "NNTP" class supports the
"with" statement to unconditionally consume "OSError" exceptions
and to close the NNTP connection when done, e.g.:
>>> from nntplib import NNTP
>>> with NNTP('news.gmane.org') as n:
... n.group('gmane.comp.python.committers')
... # doctest: +SKIP
('211 1755 1 1755 gmane.comp.python.committers', 1755, 1, 1755, 'gmane.comp.python.committers')
>>>
Changed in version 3.2: *usenetrc* is now "False" by default.
Changed in version 3.3: Support for the "with" statement was added.
class nntplib.NNTP_SSL(host, port=563, user=None, password=None, ssl_context=None, readermode=None, usenetrc=False[, timeout])
Return a new "NNTP_SSL" object, representing an encrypted
connection to the NNTP server running on host *host*, listening at
port *port*. "NNTP_SSL" objects have the same methods as "NNTP"
objects. If *port* is omitted, port 563 (NNTPS) is used.
*ssl_context* is also optional, and is a "SSLContext" object.
Please read Security considerations for best practices. All other
parameters behave the same as for "NNTP".
Note that SSL-on-563 is discouraged per **RFC 4642**, in favor of
STARTTLS as described below. However, some servers only support
the former.
New in version 3.2.
Changed in version 3.4: The class now supports hostname check with
"ssl.SSLContext.check_hostname" and *Server Name Indication* (see
"ssl.HAS_SNI").
exception nntplib.NNTPError
Derived from the standard exception "Exception", this is the base
class for all exceptions raised by the "nntplib" module. Instances
of this class have the following attribute:
response
The response of the server if available, as a "str" object.
exception nntplib.NNTPReplyError
Exception raised when an unexpected reply is received from the
server.
exception nntplib.NNTPTemporaryError
Exception raised when a response code in the range 400–499 is
received.
exception nntplib.NNTPPermanentError
Exception raised when a response code in the range 500–599 is
received.
exception nntplib.NNTPProtocolError
Exception raised when a reply is received from the server that does
not begin with a digit in the range 1–5.
exception nntplib.NNTPDataError
Exception raised when there is some error in the response data.
NNTP Objects
============
When connected, "NNTP" and "NNTP_SSL" objects support the following
methods and attributes.
Attributes
----------
NNTP.nntp_version
An integer representing the version of the NNTP protocol supported
by the server. In practice, this should be "2" for servers
advertising **RFC 3977** compliance and "1" for others.
New in version 3.2.
NNTP.nntp_implementation
A string describing the software name and version of the NNTP
server, or "None" if not advertised by the server.
New in version 3.2.
Methods
-------
The *response* that is returned as the first item in the return tuple
of almost all methods is the server’s response: a string beginning
with a three-digit code. If the server’s response indicates an error,
the method raises one of the above exceptions.
Many of the following methods take an optional keyword-only argument
*file*. When the *file* argument is supplied, it must be either a
*file object* opened for binary writing, or the name of an on-disk
file to be written to. The method will then write any data returned by
the server (except for the response line and the terminating dot) to
the file; any list of lines, tuples or objects that the method
normally returns will be empty.
Changed in version 3.2: Many of the following methods have been
reworked and fixed, which makes them incompatible with their 3.1
counterparts.
NNTP.quit()
Send a "QUIT" command and close the connection. Once this method
has been called, no other methods of the NNTP object should be
called.
NNTP.getwelcome()
Return the welcome message sent by the server in reply to the
initial connection. (This message sometimes contains disclaimers
or help information that may be relevant to the user.)
NNTP.getcapabilities()
Return the **RFC 3977** capabilities advertised by the server, as a
"dict" instance mapping capability names to (possibly empty) lists
of values. On legacy servers which don’t understand the
"CAPABILITIES" command, an empty dictionary is returned instead.
>>> s = NNTP('news.gmane.org')
>>> 'POST' in s.getcapabilities()
True
New in version 3.2.
NNTP.login(user=None, password=None, usenetrc=True)
Send "AUTHINFO" commands with the user name and password. If
*user* and *password* are "None" and *usenetrc* is true,
credentials from "~/.netrc" will be used if possible.
Unless intentionally delayed, login is normally performed during
the "NNTP" object initialization and separately calling this
function is unnecessary. To force authentication to be delayed,
you must not set *user* or *password* when creating the object, and
must set *usenetrc* to False.
New in version 3.2.
NNTP.starttls(ssl_context=None)
Send a "STARTTLS" command. This will enable encryption on the NNTP
connection. The *ssl_context* argument is optional and should be a
"ssl.SSLContext" object. Please read Security considerations for
best practices.
Note that this may not be done after authentication information has
been transmitted, and authentication occurs by default if possible
during a "NNTP" object initialization. See "NNTP.login()" for
information on suppressing this behavior.
New in version 3.2.
Changed in version 3.4: The method now supports hostname check with
"ssl.SSLContext.check_hostname" and *Server Name Indication* (see
"ssl.HAS_SNI").
NNTP.newgroups(date, *, file=None)
Send a "NEWGROUPS" command. The *date* argument should be a
"datetime.date" or "datetime.datetime" object. Return a pair
"(response, groups)" where *groups* is a list representing the
groups that are new since the given *date*. If *file* is supplied,
though, then *groups* will be empty.
>>> from datetime import date, timedelta
>>> resp, groups = s.newgroups(date.today() - timedelta(days=3))
>>> len(groups) # doctest: +SKIP
85
>>> groups[0] # doctest: +SKIP
GroupInfo(group='gmane.network.tor.devel', last='4', first='1', flag='m')
NNTP.newnews(group, date, *, file=None)
Send a "NEWNEWS" command. Here, *group* is a group name or "'*'",
and *date* has the same meaning as for "newgroups()". Return a
pair "(response, articles)" where *articles* is a list of message
ids.
This command is frequently disabled by NNTP server administrators.
NNTP.list(group_pattern=None, *, file=None)
Send a "LIST" or "LIST ACTIVE" command. Return a pair "(response,
list)" where *list* is a list of tuples representing all the groups
available from this NNTP server, optionally matching the pattern
string *group_pattern*. Each tuple has the form "(group, last,
first, flag)", where *group* is a group name, *last* and *first*
are the last and first article numbers, and *flag* usually takes
one of these values:
* "y": Local postings and articles from peers are allowed.
* "m": The group is moderated and all postings must be approved.
* "n": No local postings are allowed, only articles from peers.
* "j": Articles from peers are filed in the junk group instead.
* "x": No local postings, and articles from peers are ignored.
* "=foo.bar": Articles are filed in the "foo.bar" group instead.
If *flag* has another value, then the status of the newsgroup
should be considered unknown.
This command can return very large results, especially if
*group_pattern* is not specified. It is best to cache the results
offline unless you really need to refresh them.
Changed in version 3.2: *group_pattern* was added.
NNTP.descriptions(grouppattern)
Send a "LIST NEWSGROUPS" command, where *grouppattern* is a wildmat
string as specified in **RFC 3977** (it’s essentially the same as
DOS or UNIX shell wildcard strings). Return a pair "(response,
descriptions)", where *descriptions* is a dictionary mapping group
names to textual descriptions.
>>> resp, descs = s.descriptions('gmane.comp.python.*')
>>> len(descs) # doctest: +SKIP
295
>>> descs.popitem() # doctest: +SKIP
('gmane.comp.python.bio.general', 'BioPython discussion list (Moderated)')
NNTP.description(group)
Get a description for a single group *group*. If more than one
group matches (if ‘group’ is a real wildmat string), return the
first match. If no group matches, return an empty string.
This elides the response code from the server. If the response
code is needed, use "descriptions()".
NNTP.group(name)
Send a "GROUP" command, where *name* is the group name. The group
is selected as the current group, if it exists. Return a tuple
"(response, count, first, last, name)" where *count* is the
(estimated) number of articles in the group, *first* is the first
article number in the group, *last* is the last article number in
the group, and *name* is the group name.
NNTP.over(message_spec, *, file=None)
Send an "OVER" command, or an "XOVER" command on legacy servers.
*message_spec* can be either a string representing a message id, or
a "(first, last)" tuple of numbers indicating a range of articles
in the current group, or a "(first, None)" tuple indicating a range
of articles starting from *first* to the last article in the
current group, or "None" to select the current article in the
current group.
Return a pair "(response, overviews)". *overviews* is a list of
"(article_number, overview)" tuples, one for each article selected
by *message_spec*. Each *overview* is a dictionary with the same
number of items, but this number depends on the server. These
items are either message headers (the key is then the lower-cased
header name) or metadata items (the key is then the metadata name
prepended with "":""). The following items are guaranteed to be
present by the NNTP specification:
* the "subject", "from", "date", "message-id" and "references"
headers
* the ":bytes" metadata: the number of bytes in the entire raw
article (including headers and body)
* the ":lines" metadata: the number of lines in the article body
The value of each item is either a string, or "None" if not
present.
It is advisable to use the "decode_header()" function on header
values when they may contain non-ASCII characters:
>>> _, _, first, last, _ = s.group('gmane.comp.python.devel')
>>> resp, overviews = s.over((last, last))
>>> art_num, over = overviews[0]
>>> art_num
117216
>>> list(over.keys())
['xref', 'from', ':lines', ':bytes', 'references', 'date', 'message-id', 'subject']
>>> over['from']
'=?UTF-8?B?Ik1hcnRpbiB2LiBMw7Z3aXMi?= <martin@v.loewis.de>'
>>> nntplib.decode_header(over['from'])
'"Martin v. Löwis" <martin@v.loewis.de>'
New in version 3.2.
NNTP.help(*, file=None)
Send a "HELP" command. Return a pair "(response, list)" where
*list* is a list of help strings.
NNTP.stat(message_spec=None)
Send a "STAT" command, where *message_spec* is either a message id
(enclosed in "'<'" and "'>'") or an article number in the current
group. If *message_spec* is omitted or "None", the current article
in the current group is considered. Return a triple "(response,
number, id)" where *number* is the article number and *id* is the
message id.
>>> _, _, first, last, _ = s.group('gmane.comp.python.devel')
>>> resp, number, message_id = s.stat(first)
>>> number, message_id
(9099, '<20030112190404.GE29873@epoch.metaslash.com>')
NNTP.next()
Send a "NEXT" command. Return as for "stat()".
NNTP.last()
Send a "LAST" command. Return as for "stat()".
NNTP.article(message_spec=None, *, file=None)
Send an "ARTICLE" command, where *message_spec* has the same
meaning as for "stat()". Return a tuple "(response, info)" where
*info* is a "namedtuple" with three attributes *number*,
*message_id* and *lines* (in that order). *number* is the article
number in the group (or 0 if the information is not available),
*message_id* the message id as a string, and *lines* a list of
lines (without terminating newlines) comprising the raw message
including headers and body.
>>> resp, info = s.article('<20030112190404.GE29873@epoch.metaslash.com>')
>>> info.number
0
>>> info.message_id
'<20030112190404.GE29873@epoch.metaslash.com>'
>>> len(info.lines)
65
>>> info.lines[0]
b'Path: main.gmane.org!not-for-mail'
>>> info.lines[1]
b'From: Neal Norwitz <neal@metaslash.com>'
>>> info.lines[-3:]
[b'There is a patch for 2.3 as well as 2.2.', b'', b'Neal']
NNTP.head(message_spec=None, *, file=None)
Same as "article()", but sends a "HEAD" command. The *lines*
returned (or written to *file*) will only contain the message
headers, not the body.
NNTP.body(message_spec=None, *, file=None)
Same as "article()", but sends a "BODY" command. The *lines*
returned (or written to *file*) will only contain the message body,
not the headers.
NNTP.post(data)
Post an article using the "POST" command. The *data* argument is
either a *file object* opened for binary reading, or any iterable
of bytes objects (representing raw lines of the article to be
posted). It should represent a well-formed news article, including
the required headers. The "post()" method automatically escapes
lines beginning with "." and appends the termination line.
If the method succeeds, the server’s response is returned. If the
server refuses posting, a "NNTPReplyError" is raised.
NNTP.ihave(message_id, data)
Send an "IHAVE" command. *message_id* is the id of the message to
send to the server (enclosed in "'<'" and "'>'"). The *data*
parameter and the return value are the same as for "post()".
NNTP.date()
Return a pair "(response, date)". *date* is a "datetime" object
containing the current date and time of the server.
NNTP.slave()
Send a "SLAVE" command. Return the server’s *response*.
NNTP.set_debuglevel(level)
Set the instance’s debugging level. This controls the amount of
debugging output printed. The default, "0", produces no debugging
output. A value of "1" produces a moderate amount of debugging
output, generally a single line per request or response. A value
of "2" or higher produces the maximum amount of debugging output,
logging each line sent and received on the connection (including
message text).
The following are optional NNTP extensions defined in **RFC 2980**.
Some of them have been superseded by newer commands in **RFC 3977**.
NNTP.xhdr(hdr, str, *, file=None)
Send an "XHDR" command. The *hdr* argument is a header keyword,
e.g. "'subject'". The *str* argument should have the form "'first-
last'" where *first* and *last* are the first and last article
numbers to search. Return a pair "(response, list)", where *list*
is a list of pairs "(id, text)", where *id* is an article number
(as a string) and *text* is the text of the requested header for
that article. If the *file* parameter is supplied, then the output
of the "XHDR" command is stored in a file. If *file* is a string,
then the method will open a file with that name, write to it then
close it. If *file* is a *file object*, then it will start calling
"write()" on it to store the lines of the command output. If *file*
is supplied, then the returned *list* is an empty list.
NNTP.xover(start, end, *, file=None)
Send an "XOVER" command. *start* and *end* are article numbers
delimiting the range of articles to select. The return value is
the same of for "over()". It is recommended to use "over()"
instead, since it will automatically use the newer "OVER" command
if available.
NNTP.xpath(id)
Return a pair "(resp, path)", where *path* is the directory path to
the article with message ID *id*. Most of the time, this extension
is not enabled by NNTP server administrators.
Deprecated since version 3.3: The XPATH extension is not actively
used.
Utility functions
=================
The module also defines the following utility function:
nntplib.decode_header(header_str)
Decode a header value, un-escaping any escaped non-ASCII
characters. *header_str* must be a "str" object. The unescaped
value is returned. Using this function is recommended to display
some headers in a human readable form:
>>> decode_header("Some subject")
'Some subject'
>>> decode_header("=?ISO-8859-15?Q?D=E9buter_en_Python?=")
'Débuter en Python'
>>> decode_header("Re: =?UTF-8?B?cHJvYmzDqG1lIGRlIG1hdHJpY2U=?=")
'Re: problème de matrice'
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