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Re: [sieve] Fwd: New Version Notification for draft-bosch-sieve-duplicate-01.txt

2013-03-15 16:10:27
A minor comment: I'm not crazy about the ":value" tag name, as I find it
less self-explanatory than I'd prefer.  I'd propose instead ":key", or 
or maybe ":uniqueid".  

Regards,

Kristin

On Mar 12, 2013, at 2:14 PM, Stephan Bosch wrote:

Hi Alexey,

On 3/10/2013 3:01 PM, Alexey Melnikov wrote:
On 9 Mar 2013, at 11:08, Stephan Bosch <stephan(_at_)rename-it(_dot_)nl> 
wrote:

I made a new version of the "duplicate" draft. It should address the 
comments by Ned and Alexey.
Any thoughts about this?
This looks much better, thank you.

One new issue is that I don't understand how :value works. Maybe it is a 
Sunday morning effect. Maybe you can show an example or two?

To detect duplicates, some more or less unique identifying string value must 
be extracted from the message and compared between deliveries. For most 
cases, the contents of the Message-ID header is the best choice; that is what 
it is meant for. However, to accommodate more complex uses, the duplicate 
test has the flexibility to choose a different string value for comparison. 
Using the :value argument, the string value can be set manually to an 
arbitrary string. Typically, one would compose this string using variable 
substitutions. One can for example compose it from parts of a header, the 
envelope, multiple headers, parts of the message body or even the current 
date; whatever is appropriate for the application.

There is one example of the use of :value in the draft (the second one). I 
should perhaps make the subject header structure a bit more complex to 
justify its use in this example (because :header would work here as well).

Another example would be the following scenario. A mail user receives XMPP 
notifications about new mail through Sieve. Sometimes a single contact sends 
many messages in a short period of time and the user wants to prevent being 
notified of all of those messages. He wants to be notified about messages 
from each person at most once per 30 minutes. He writes the following script:

require ["variables", "envelope","enotify", "duplicate"];

if envelope :matches "from" "*" { set "sender" "${1}"; }
if header :matches "subject" "*" { set "subject" "${1}"; }

if not duplicate :seconds 1800 :value "${sender}") {
   notify :message "[SIEVE] ${from}: ${subject}" 
"xmpp:user(_at_)im(_dot_)example(_dot_)com";
}

So this example uses the message envelope sender rather than the Message-ID 
header as an identifier for duplicate checking.

This example can be extended to allow multiple messages from the same sender 
in close succession as long as the discussed topic is different. This could 
be done as follows:

require ["variables", "envelope","enotify", "duplicate"];

if envelope :matches "from" "*" { set "sender" "${1}"; }
if header :matches "subject" "*" { set "subject" "${1}"; }

if string :comparator "i;ascii-casemap" :matches "${subject}" "Re:*" {
   set "topic" "${1}";
} else {
   set "topic" "${subject}";
}

if not duplicate :seconds 1800 :value "${sender} ${topic}") {
   notify :message "[SIEVE] ${from}: ${topic}" 
"xmpp:user(_at_)im(_dot_)example(_dot_)com";
}

Regards,

Stephan.





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