FilterScript is a minimal Thunderbird extension for processing messages using external programs.
FilterScript came about when I wanted a way to email myself URLs, and have them stored in my Firefox bookmarks database. Although I knew how to interact with Firefox, Thunderbird did not provide an easy way to pass the contents of an email message to an external program automatically. After several hours of frustration, this extension was born.
Simply run the script make-xpi.sh in the main directory - it should generate
a fie called filterscript@adam.marchetti.xpi. You should be able to install
this by dragging and dropping this file into the Thunderbird Add-ons Manager.
Note that if you have a more recent version than 42, you will need to change the
version string in extension/install.rdf. Look for the line:
<em:maxVersion>42.*<em:maxVersion>
Replace this with whatever version you run. I tried to avoid using any experimental APIs (although I probably did use a couple deprecated functions), so FilterScript will probably be runnable on most versions of Thunderbird. I haven't yet tested with anything but 31.7.0, since that is what Ubuntu is distributing at the moment.
This extension is not guaranteed to be portable to anything but Linux systems
right now (by virtue of hardcoding /tmp).
After installing the extension, a new menu called "FilterScript" will appear on the main screen. This menu will have one entry, called "Settings."
On this dialog box, simply click the Open button and select the executable file that you wish to use as the filter script.
Next, open up "Tools > Message Filters" and either create or edit a filter. You will see that a new message action has been created, called Run Filter Script. Add it to the chain of actions, and the filter script that you specified earlier will be run on any message that matches the filter. (Note that there isn't yet a way to assign a different script to each filter - you have to use a single, global filter script for all your different filters)
One of the simplest filter scripts looks like this (in Bourne Shell):
#!/bin/sh
cat $1 > /tmp/last-message-body
This illustrates a couple of features about the way that FilterScripts calls your script:
- The full MIME headers of the message are dumped. This makes it possible to get all information about the message (including attachments, via the multipart MIME type), but it means that scripts should probably be written in a language that has good support for MIME email.
- The message body is stored in a temporary file, given as the first command
line argument (hence the
$1). Note that FilterScripts will delete the temporary file for you, so there is no need to remove it in your script.
In addition, a few further caveats are worth noting:
- The working directory of your script will be (from your perspective),
arbitrary - if it is important to access the directory the script is
accessed in, your script will have to determine where that is and
cditself. - The standard output and standard error will end upon the console that
Thunderbird is attached to. Under most circumstances, this will be
/dev/nullsince desktop environments tend to throw away the console output of programs launched via graphical menus.
To be of the most use possible, I am releasing this under the CC0 license.
Big thanks to the authors on MDN, and the authors of Enigmail, which was a helpful reference for some of the under-documented parts of the Thunderbird API.
In addition, thanks to GitHub user mic-rigaud for pointing me to unfamiliar parts of the Thunderbird API that helped in solving bug #1.