This is a filtering system I wrote for use with the Sup email client <sup.rubyforge.org>. Be warned that I am not maintaining it, and it is not very well tested. But if you find it useful, fork the repository and run with it! If you want to take over developing it, email me and I’ll give you my blessing.

• John Croisant (jacius at gmail)

1. Copy filters.example.yaml to ~/.sup/filters.yaml and customize.

2. Copy lib/filter.rb to ~/.sup/lib/filter.rb.

3. Copy or append hooks/before-add-message.rb to ~/.sup/hooks/before-add-message.rb

4. Start sup or sup-sync. Filters run when a message is added to the index (i.e. after polling).

Your filter rules are defined in a YAML file, by default located at ~/.sup/filters.yaml. You can customize hooks/before-add-message.rb to pass an absolute file path or a hash of loaded filter rules as the second argument to SupFilters.filter_message.

Each filter rule has two parts: a condition and an action. Conditions are things like “when the message is from Joe Schmoe” or “when the subject has the word ‘ruby’ in it”. Actions are things like “add a label” or “mark it as spam”.

Filters are defined as key/value pairs (Hash/Dictionary) in a YAML file (see filters.example.yaml). The key is the condition, and the value is the action. It’s also possible to have multiple conditions and/or multiple actions per rule, by using an arrays for the key or value. (The YAML syntax for using an array as a key is a bit awkward, but see filters.example.yaml for an example.)

Each condition or action is a string in the form “type:param”. Param is usually interpreted as a regular expression, but that varies depending on the type of condition/action. Some conditions or actions take no params, in which case you can just do “type”.

You can also prefix conditions or actions with a “-” (minus sign) to mean the opposite. For example, the condition “from:joe.schmoe@” matches messages that are from Joe Schmoe. “-from:joe.schmoe@” matches messages that are NOT from Joe Schmoe. The action “label:ruby” adds the label “ruby”, while “-label:ruby” REMOVES the label “ruby”.

match:regexp

regexp matches anywhere in the raw message text.

from:regexp

regexp matches the “From:” field (name or address).

to:regexp

regexp matches the “To:” field (name or address).

subj:regexp

regexp matches the “Subject:” field.

list:regexp

regexp matches the “List-Post:” field.

label:name

message has label “name”.

spam

message is marked as spam. (Same as “label:spam”.)

inbox

message is in the inbox. (Same as “label:inbox”.)

deleted

message is marked as deleted. (Same as “label:deleted”.)

starred

message is starred. (Same as “label:starred”.)

label:name

add the label “name”.

L:name

same as “label:name”. For convenience/brevity.

-label:*

removes all labels. “-L:*” also works. There is no positive version (i.e. “label:*” is not valid).

inbox

add the message in the inbox. (Same as “label:inbox”.)

unread

mark the message as unread. (Same as “label:unread” or “-read”.)

read

mark the message as read. (Same as “-label:unread” or “-unread”.)

star

star the message. (Same as “label:star”.)

spam

mark the message as spam. (Same as “label:spam”.)

deleted

mark the message as deleted. (Same as “label:deleted”.)

delete

same as “deleted”.

filter.rb is licensed under the following terms (the “MIT License”):

Copyright © 2010 John Croisant

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.