Ubuntu Manpage: feed2exec - The programmable feed reader

NAME

       feed2exec - The programmable feed reader

SYNOPSIS

       feed2exec {add,ls,rm,fetch,import,export}

DESCRIPTION

       This  command  will  take a configured set of feeds and fire specific plugin for every new
       item found in the feed.

OPTIONS

          --version
                 Show the version and exit.

          --loglevel
                 choose specific log level [default: WARNING]

          -v, --verbose
                 show what is happening (loglevel: VERBOSE)

          -d, --debug
                 show debugging information (loglevel: DEBUG)

          --syslog LEVEL
                 send LEVEL logs to syslog

          --config TEXT
                 use a different configuration file

          --database DB
                 use a different database

          -h, --help
                 Show this message and exit.

EXAMPLES

       Simple run with no side effects:

          feed2exec parse https://www.nasa.gov/rss/dyn/breaking_news.rss --output echo --args '{item.title}'

       Saving feed items to a Maildir folder:

          feed2exec add "NASA breaking news" https://www.nasa.gov/rss/dyn/breaking_news.rss --folder nasa
          feed2exec fetch

       This creates the equivalent of this configuration file in ~/.config/feed2exec.ini:

          [DEFAULT]
          output = feed2exec.plugins.maildir
          mailbox = ~/Maildir

          [NASA breaking news]
          folder = nasa
          url = https://www.nasa.gov/rss/dyn/breaking_news.rss

       Send new feed items to Transmission:

          feed2exec add "Example torrent list" http://example.com/torrents/feed --output transmission --folder /srv/incoming

       Send new feed items to Mastodon, using the toot commandline client:

          feed2exec add "My site" http://example.com/blog/feed --output exec --args 'toot post "{item.title} {item.link}"'

       Send new feed items to Twitter, using the tweet commandline client from python-twitter:

          feed2exec add "My site on twitter" http://example.com/blog/feed --output exec --args 'tweet "{item.title:40s} {item.link:100s}"'

       Show feed contents:

          feed2exec add "NASA breaking news" https://www.nasa.gov/rss/dyn/breaking_news.rss --output echo --args "{item.title} {item.link}"
          feed2exec fetch

COMMANDS

• parse

• fetch

• add

• ls

• rm

• import

• export

parse
Usage:

parse URL
[--output PLUGIN [--args ARG [ARG [...]]]
[--filter PLUGIN] [--filter_args ARG [ARG [...]]]
[--mailbox PATH] [--folder PATH]

The parse command loads and parses a single feed, without touching the database. This is
similar to calling add then fetch on a single feed, but the feed is not kept in the
configuration. This is designed to make quick tests with a new feed. The arguments are the
same as the add command.

fetch
Usage:

fetch [--parallel | -p | --jobs N | -j N] [--force | -f] [--pattern pattern]

The fetch command iterates through all the configured feeds or those matching the pattern
substring if provided.

Options:

--pattern TEXT
only fetch feeds matchin name or URL

--parallel
parse feeds in the background to improve performance

-j,--jobs N
start N jobs in parallel, implies --parallel which defaults to the number of
CPUs detected on the machine

-f, --force
skip reading and writing the cache and will consider all entries as new

-n, --catchup
tell output plugins plugins to simulate their actions

add
Usage:

add NAME URL
[--output PLUGIN [--args ARG [ARG [...]]]
[--filter PLUGIN] [--filter_args ARG [ARG [...]]]
[--mailbox PATH] [--folder PATH]

The add command adds the given feed NAME that will be fetched from the provided URL.

Options:

--output PLUGIN
use PLUGIN as an output module. defaults to maildir to store in a mailbox. use
null or echo to just fetch the feed without doing anything. Modules are searched
in the feed2exec.plugins package unless the name contains a dot in which case
the whole Python search path is used.

--args ARGS
pass arguments ARGS to the output plugin. supports interpolation of feed
parameters using, for example {title}

--filter PLUGIN
filter feed items through the PLUGIN filter plugin

--filter_args ARGS
arguments passed to the filter plugin

--mailbox PATH
folder to store email into, defaults to ~/Maildir.

--folder PATH
subfolder to store the email into

Those parameters are documented more extensively in their equivalent settings in the
configuration file, see below.

ls
The ls command lists all configured feeds as JSON packets.

rm
Usage:

rm NAME

Remove the feed named NAME from the configuration.

import
Usage:

import PATH

Import feeds from the file named PATH. The file is expected to have outline elements and
only the title and xmlUrl elements are imported, as NAME and URL parameters, respectively.

export
Usage:

export PATH

Export feeds into the file named PATH. The file will use the feed NAME elements as title
and the URL as xmlUrl.

FILES

Configuration file
The configuration file is loaded from (and written to, by add) ~/.config/feed2exec.ini or
$XDG_CONFIG_HOME/feed2exec.ini. It can also be specified with the --config commandline
parameter. This is an example configuration snippet:

[NASA breaking news]
url = https://www.nasa.gov/rss/dyn/breaking_news.rss
output = feed2exec.plugins.echo
args = {title} {link}

Naturally, those settings can be changed directly in the config file. Note that there is a
[DEFAULT] section that can be used to apply settings to all feeds. For example, this will
make all feeds store new items in a maildir subfolder:

[DEFAULT]
output = feed2exec.plugins.maildir
folder = feeds

This way individual feeds do not need to be individually configured.

NOTE:
feed2exec does not take care of adding the folder to “subscriptions” in the mailbox. it
is assumed that folders are auto-susbcribed or the user ignores subscription. if that
is a problem, you should subscribe to the folder by hand in your email client when you
add a new config. you can also subscribe to a folder (say feeds above) directly using
the doveadm mailbox subscribe feeds command in Dovecot, for example.

The following configuration parameters are supported:

name Human readable name for the feed. Equivalent to the NAME argument in the add
command.

url Address to fetch the feed from. Can be HTTP or HTTPS, but also file:// resources
for test purposes.

output Output plugin to use. Equivalent to the --output option in the add command.

args Arguments to pass to the output plugin. Equivalent to the --args option in the
add command.

filter Filter plugin to use. Equivalent to the --filter option in the add command.

mailbox
Store emails in that mailbox prefix. Defaults to ~/Maildir.

folder Subfolder to use when writing to a mailbox. By default, a slugified version of
the feed name (where spaces and special character are replaced by -) is used.
For example, the feed named “NASA breaking news” would be stored in
~/Maildir/nasa-breaking-news/. Note that the mailbox prefix is used only if the
folder path is relative.

catchup
Skip to the latest feed items. The feed is still read and parsed, and new feed
items are added to the database, but output plugins are never called.

pause Completely skip feed during fetch or parse. Similar to catchup, but doesn’t
fetch the feed at all and doesn’t touch the cache.

Here is a more complete example configuration with all the settings used:

# this section will apply to all feeds
[DEFAULT]
# special folder location for maildir. I use this when I have multiple
# accounts synchronized with Offlineimap
mailbox = ~/Maildir/Remote/

# a feed to store NASA breaking news entry in a "nasa" subfolder
# this also demonstrates the droptitle filter
[NASA breaking news]
url = https://www.nasa.gov/rss/dyn/breaking_news.rss
folder = nasa
filter = feed2exec.plugins.droptitle
filter_args = trump

# some maildir storage require dots to get subfolders. for example,
# this will store messages in INBOX/feeds/images/ on Dovecot
[NASA image of the day]
url = https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss
folder = .feeds.images

# same feed, but save to wayback machine
[NASA IOTD wayback]
url = https://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss
output = feed2exec.plugins.wayback

# this demonstrates the emptysummary filter, which fixes GitHub feeds
# that lack a proper summary
[restic]
url = https://github.com/restic/restic/tags.atom
filter = feed2exec.plugins.emptysummary

# saving to a mbox folder, one file per feed instead of one file per item
[International Space Station Reports]
url = http://blogs.nasa.gov/stationreport/feed/
mailbox = ~/Mail/
folder = stationreport.mbx

# simple generic exec call example: check for broken links using linkchecker
[NASA linkchecker]
url = https://www.nasa.gov/rss/dyn/breaking_news.rss
output = feed2exec.plugins.exec
args = linkchecker --check-extern --no-robots --recursion-level 1 --quiet '{item.link}'

# same, but with a Ikiwiki RSS feed, which needs fixing
[Ikiwiki linkchecker]
url = http://ikiwiki.info/recentchanges/index.rss
output = feed2exec.plugins.exec
filter = feed2exec.plugins.ikiwiki_recentchanges
args = linkchecker --check-extern --no-robots --recursion-level 1 --quiet '{item.link}'

# retweet hurricane news
[NASA Hurricane breaking news]
url = https://www.nasa.gov/rss/dyn/hurricaneupdate.rss
output = feed2exec.plugins.exec
args = tweet "{item.title:.40s} {item.link:.100s}"

# same, but on the mastodon network
#
# we can have multiple entries with the same URL without problems, as
# long as the feed name is different. it does mean that the feed will
# be fetched and parsed multiple times, unfortunately.
#
# this could be improved to include the '{item.summary}' and extra markup,
# for example.
[NASA Hurricane breaking news - Mastodon]
url = https://www.nasa.gov/rss/dyn/hurricaneupdate.rss
output = feed2exec.plugins.exec
# unfortunately, this will noisily report the URL of the posted link,
# which you may not want. to avoid that, encourage upstream to do the
# right thing: https://github.com/ihabunek/toot/issues/46 ... or use
# another tool listed here:
# https://github.com/tootsuite/documentation/blob/master/Using-Mastodon/Apps.md
args = toot post "{item.title} {item.link}"
# output is disabled here. feed will be fetched and parsed, but no
# toot will be sent
catchup = True

# same, but on the Pump.io network
[NASA Hurricane breaking news - Pump]
url = https://www.nasa.gov/rss/dyn/hurricaneupdate.rss
output = feed2exec.plugins.exec
args = p post note "{item.title} {item.link}"

# crude podcast client
[NASA Whats up?]
url = https://www.nasa.gov/rss/dyn/whats_up.rss
output = feed2exec.plugins.exec
# XXX: this doesn't handle errors properly: if there is a feed without
# enclosures, the whole thing will crash.
args = wget -P /srv/podcasts/nasa/ "{item.enclosures[0].href}"
# feed is paused here. feed will not be fetched and parsed at all and
# no post will be sent.
pause = True

# download torrents linked from a RSS feed
[torrents]
url = http://example.com/torrents.rss
output = feed2exec.plugins.exec
args = transmission-remote -a '{item.link}' -w '/srv/incoming'

# same thing with an actual plugin
[torrents]
url = http://example.com/torrents.rss
output = feed2exec.plugins.transmission
args = seedbox.example.com
folder = /srv/incoming

Cache database
The feeds cache is stored in a feed2exec.db file. It is a SQLite database and can be
inspected using standard sqlite tools. It is used to keep track of which feed and items
have been processed. To clear the cache, you can simply remove the file, which will make
the program process all feeds items from scratch again. In this case, you should use the
--catchup argument to avoid duplicate processing. You can also use the null output plugin
to the same effect.

LIMITATIONS

Feed support is only as good as feedparser library which isn’t as solid as I expected. In
particular, I had issues with feeds without dates and without guid.

Unit test coverage is incomplete, but still pretty decent, above 90%.

The exec plugin itself is not well tested and may have serious security issues.

API, commandline interface, configuration file syntax and database format can be changed
until the 1.0 release is published, at which point normal Semantic Versioning semantics
apply.

The program is written mainly targeting Python 3.5 and 3.7, but should support later
releases as well. See the setup.py classification for an authoritative reference. Python
2.7 is not supported anymore.

The SQL storage layer is badly written and is known to trigger locking issues with SQLite
when doing multiprocessing. The global LOCK object could be used to work around this issue
but that could mean pretty bad coupling. A good inspiration may be the beets story about
this problem. And of course, another alternative would be to considering something like
SQLalchemy instead of rolling our own ORM. There has, however, been some improvements to
the locking recently, although that has been done with thread instead of process-specific
locks.

Older feed items are not purged from the database when they disappear from the feed, which
may lead to database bloat in the long term. Similarly, there is no way for plugins to
remove old entry that expire from the feed.

AUTHOR

       Antoine Beaupré

COPYRIGHT

       Copyright (C) 2016-2019  Antoine Beaupré