Konfekt/mutt-ical

This single-file Python script mutt-ical.py displays and replies to Icalendar invitations (.ics files) from mutt. It requires Mutt and Python with the Vobject Python package that can be installed with pip install --user git+https://github.com/py-vobject/vobject.

Installing

Copy the script into a folder in your $PATH, (or specify the $PATH in your mailcap and muttrc files). Mark it executable by chmod +x. We will assume that you copied it into ~/bin so that its full path is ~/bin/mutt-ical.py.

Initial Setup

To view the calendar entry in mutt by opening the calendar entry in the attachment view (usually opened by hitting v after having selected a mail in mutt), add to your mailcap file (found at '~/.mailcap, /etc/mailcap or $mailcap_path set in muttrc) the following lines:

text/calendar;    ~/bin/mutt-ical.py -D %s; copiousoutput
text/x-vcalendar; ~/bin/mutt-ical.py -D %s; copiousoutput
application/ics;  ~/bin/mutt-ical.py -D %s; copiousoutput

To view the calendar entry by opening a selected a mail in mutt, add to your .muttrc the following lines:

auto_view text/calendar text/x-vcalendar application/ics text/plain text/html
alternative_order text/calendar text/x-vcalendar application/ics text/plain text/html

Here the second line ensures that the calendar entry is displayed before the message text.

To answer a calendar entry by pressing a in the attachment view (usually opened by hitting v after having selected a mail in mutt), add to your .muttrc a line such as

macro attach a \
    "<pipe-entry>iconv -c --to-code=UTF-8 > ~/.cache/mutt.ics<enter><shell-escape>~/bin/mutt-ical.py -i -e your.email@address -s 'msmtp --account=work' ~/.cache/mutt.ics<enter>" \
    "answer appointment request"

Here you need to customize the email address your.email@address and the send command msmtp --account=work. If -s is not set, the Mutt setting $sendmail will be used.

To optionally open the Icalendar in your favorite desktop calendar application, such as Ical, run xdg-open ~/.cache/mutt.ics (on Linux, respectively open ~/.cache/mutt.ics on Mac OS) after the mutt-ical.py command, for example

macro attach a \
    "<pipe-entry>iconv -c --to-code=UTF-8 > ~/.cache/mutt.ics<enter><shell-escape>~/bin/mutt-ical.py -i -e your.email@address -s 'msmtp --account=work' ~/.cache/mutt.ics && xdg-open ~/.cache/mutt.ics<enter>" \
    "reply to appointment request"

Usage

If you configure auto_view (as above), then the description should be visible in the pager. (Otherwise view the attachements (usually by hitting 'v'), select and open the Icalendar entry.) To answer, just open the Icalendar file from mutt:

View the attachements (usually 'v')
Select the text/calendar entry
Hit 'a'
Choose your answer

Documentation

The script supports the following options: -i, -a, -d, -t, -D, and -s. The -e option followed by an email address and the path to an .ics file are required. If the -D option is used, the script will display the event details and terminate without sending any replies. The -i, -a, -d, and -t options are mutually exclusive; the last one specified determines the response type sent. By default, the script will use Mutt's sendmail setting to send the answer, unless the -s option is used to override it.

-e <your.email@address>
    Specify the email address to send the answer from. This should be the email address that received the invitation.

-i
    Interactive mode. Prompt for user input to accept, decline, or tentatively accept the invitation.

-a
    Accept the invitation automatically without prompting.

-d
    Decline the invitation automatically without prompting.

-t
    Tentatively accept the invitation automatically without prompting.

-D
    Display only. Show the event details but do not send any answer.

-s <sendmail command>
    Specify the sendmail command to use for sending the email. If not set, the default Mutt setting will be used.

filename.ics
    The .ics file to be processed. This should be the invitation file received.

Usage:

    mutt-ical.py [OPTIONS] -e your@email.address filename.ics

Make sure to replace the placeholder your.email@address with your actual email address and filename.ics with the path to the .ics file when running the script.

Hints

Mac OS X iCal Users can force iCal to stop trying to send mail on your behalf by replacing the file /Applications/iCal.app/Contents/Resources/Scripts/Mail.scpt with your own ActionScript. Martin Sander went with the following: error number -128 Which tells it that the user cancelled the action.

Open AppleScript Editor, paste the code from above into a new script, then save it.
Move the old script /Applications/iCal.app/Contents/Resources/Scripts/Mail.scpt just in case you want to re-enable the functionality.
Copy your new script into place.

Inspiration

This forks Martin Sander's whose (MIT) license restrictions apply, and which was inspired by accept.py and Rubyforge.org Samples.

Konfekt / mutt-ical