imm: Execute arbitrary callbacks for each element of RSS/Atom feeds

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Dependencies aeson, async, atom-conduit (>=0.7), base-noprelude (>=4.7 && <5), binary, blaze-html, blaze-markup, bytestring, conduit, containers, dhall (>=1.27), directory (>=, fast-logger, filepath, hashable, imm, microlens, mime-mail, monad-time, msgpack, opml-conduit (>=0.7), optparse-applicative, pipes, pipes-bytestring, prettyprinter, prettyprinter-ansi-terminal, refined (>=0.4.1), relude, rss-conduit (>=0.5.1), safe, safe-exceptions, stm, stm-chans, streaming-bytestring, streaming-with, text, time, timerep (>=, typed-process, uri-bytestring, xml-conduit (>=1.5), xml-types [details]
License CC0-1.0
Author kamaradclimber, koral
Category Web
Home page
Source repo head: git clone git://
Uploaded by koral at 2020-05-30T08:44:14Z


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imm is a program that executes arbitrary callbacks (e.g. sending a mail, or writing a file) for each element of RSS/Atom feeds.

imm is written in Haskell, configured in Dhall. The project includes:


Using nix

This repository includes a nix package that can be installed by running the following command at the root folder:

nix-build --attr exe

Without nix

imm's executables can be installed using cabal-install tool:

cabal install imm

Then, the following runtime dependencies must be installed separately and provided in PATH:



Callbacks are configured through the $XDG_CONFIG_HOME/imm/callbacks.dhall file. A commented template file is bundled with the project.

imm will call each callback once per feed element, and will fill its standard input (stdin) with a MessagePack-encoded object structured as follows:

  "feed": "RSS document or Atom feed (XML)",
  "element": "RSS item or Atom entry (XML)"

imm expects callbacks to return 0 in case of success, or any other exit code in case of failure, in which case the standard error output (stderr) will be displayed.

Example use cases

Online feed reader

For the sake of I-want-the-mutt-of-feed-readers zealots, it is possible to turn any mail reader into a feed reader, by having imm send an e-mail with unread elements to an arbitrary address. You can then browse your feeds through your favourite mail reader, and leverage any mail-related tool on your feeds. Bonus points if your mail reader is online as you can now access your feeds from any computer connected to the Internet.

Here is an example configuration:

let Callback : Type =
  { _executable : Text
  , _arguments : List Text

let sendMail =
  { _executable = "imm-sendmail"
  , _arguments = []

let config : List Callback = [ sendMail ]
in config

imm-sendmail does not have a built-in SMTP client, instead it must rely on an external SMTP client program, which is configured in $XDG_CONFIG_HOME/imm/sendmail.dhall (cf example bundled with the project.) imm-sendmail writes the mail bytestring to the standard input of the configured external program.

Offline read-it-later

imm is able to store a local copy of unread elements, to read them later while offline for example. External links won't work offline though.

let Callback : Type =
  { _executable : Text
  , _arguments : List Text

let writeFile =
  { _executable = "imm-writefile"
  , _arguments = [ "-d", "/path/to/folder" ]

let config : List Callback = [ writeFile ]
in config

Example usage