gnus-sieve: make it easier to customize.

gnus-sieve: make it easier to customize.

[Daniel Pittman]

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G'day.

My mail server places some particular demands on the format of Sieve scripts;
specifically, it likes to have a comment before each item to show as the
"name" of the filter rule in the web interface.

Actually trying to hack this into gnus-sieve was surprisingly difficult: the
generation process wraps the formatting of each command into the same process
that loops the overall map.

Attached is a patch that splits this out into two components: one function
that loops through newsrc and finds the groups, and another that is
responsible for generating the individual Sieve expression for a single group.

It also implements the comment-before-content used by my server, although that
is reasonably self-contained and optional; if y'all felt like taking the patch
without that I would be happy.[1]


I have papers for Gnus, and Emacs, on file, although I don't consider the
content original enough to warrant them: while it moves a whole bunch of
lines, it just moves them.  Anyway, whatever.  I hope y'all accept it. :)

Regards,
        Daniel

Footnotes: 
[1]  Specifically, I could advise the function to inject the comment
     appropriately without worrying about changes to the overall design later
     breaking my nasty hacks. :)

-- 
✣ Daniel Pittman            ✉ daniel@rimspace.net            ☎ +61 401 155 707
               ♽ made with 100 percent post-consumer electrons


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diff -u -p /home/daniel/tmp/t/gnus-sieve.el.orig /home/daniel/tmp/t/gnus-sieve.el
--- /home/daniel/tmp/t/gnus-sieve.el.orig	2009-12-04 00:18:17.978172193 +1100
+++ /home/daniel/tmp/t/gnus-sieve.el	2009-12-04 00:31:32.797180020 +1100
@@ -205,6 +205,31 @@ test as the condition and { fileinto \"g
 If CROSSPOST is nil, each conditional body contains a \"stop\" command
 which stops execution after a match is found.
 
+The function `gnus-sieve-script-one' generates the actual commands,
+while this provides the overall structure and iteration.
+
+This is returned as a string."
+  (let* ((newsrc (cdr gnus-newsrc-alist))
+	 script)
+    (dolist (info newsrc)
+      (when (or (not method)
+		(gnus-server-equal method (gnus-info-method info)))
+	(let ((spec (gnus-sieve-script-one (gnus-info-group info) crosspost)))
+	  (when spec
+	    (push spec script)))))
+    (mapconcat 'identity script "\n")))
+
+(defun gnus-sieve-script-one (group &optional crosspost)
+  "Generate a single Sieve command for a single Gnus GROUP,
+passed as an object.  Only groups having a `sieve' parameter have
+a command generated; `nil' is returned otherwise.
+
+A Sieve IF control structure is generated, having the test as the
+condition and { fileinto \"group.name\"; } as the body.
+
+If CROSSPOST is nil, each conditional body contains a \"stop\"
+command which stops execution after a match is found.
+
 For example: If the INBOX.list.sieve group has the
 
   (sieve address \"sender\" \"sieve-admin@extundo.com\")
@@ -216,22 +241,16 @@ group parameter, (gnus-sieve-script) res
   }
 
 This is returned as a string."
-  (let* ((newsrc (cdr gnus-newsrc-alist))
-	 script)
-    (dolist (info newsrc)
-      (when (or (not method)
-		(gnus-server-equal method (gnus-info-method info)))
-	(let* ((group (gnus-info-group info))
-	       (spec (gnus-group-find-parameter group 'sieve t)))
-	  (when spec
-	    (push (concat "if " (gnus-sieve-test spec) " {\n"
-			  "\tfileinto \"" (gnus-group-real-name group) "\";\n"
-			  (if crosspost
-			      ""
-			    "\tstop;\n")
-			  "}")
-		  script)))))
-    (mapconcat 'identity script "\n")))
+  (let ((spec (gnus-group-find-parameter group 'sieve t)))
+    (when spec
+      (concat (format "# %s: %s\n" (gnus-group-real-name group) spec)
+              "if " (gnus-sieve-test spec) " {\n"
+              "\tfileinto \"" (gnus-group-real-name group) "\";\n"
+              (if crosspost
+                  ""
+                "\tstop;\n")
+              "}"))))
+
 
 (provide 'gnus-sieve)
 

Diff finished.  Fri Dec  4 00:31:54 2009

Re: gnus-sieve: make it easier to customize.

[Ted Zlatanov]

On Fri, 04 Dec 2009 00:35:25 +1100 Daniel Pittman <daniel@rimspace.net> wrote: 

DP> I have papers for Gnus, and Emacs, on file, although I don't consider the
DP> content original enough to warrant them: while it moves a whole bunch of
DP> lines, it just moves them.  Anyway, whatever.  I hope y'all accept it. :)

I think your version is much easier to read and understand.  I don't use
Sieve so I can't test it but otherwise I'm in favor of comitting your
patch.

Ted

Re: gnus-sieve: make it easier to customize.

[Daniel Pittman]

Ted Zlatanov <tzz@lifelogs.com> writes:
> On Fri, 04 Dec 2009 00:35:25 +1100 Daniel Pittman <daniel@rimspace.net> wrote:
>
> DP> I have papers for Gnus, and Emacs, on file, although I don't consider the
> DP> content original enough to warrant them: while it moves a whole bunch of
> DP> lines, it just moves them.  Anyway, whatever.  I hope y'all accept it. :)
>
> I think your version is much easier to read and understand.  I don't use
> Sieve so I can't test it but otherwise I'm in favor of comitting your
> patch.

Well, the generated output is (trivially) identical to the original; it puts
us in no worse a state than the previous code, but more fine-grained.

Oh, and it actually generates a local file only; if you wish, you can test it
through generating the content and observing the output. :)

        Daniel
-- 
✣ Daniel Pittman            ✉ daniel@rimspace.net            ☎ +61 401 155 707
               ♽ made with 100 percent post-consumer electrons

Re: gnus-sieve: make it easier to customize.

[Ted Zlatanov]

On Fri, 04 Dec 2009 12:46:37 +1100 Daniel Pittman <daniel@rimspace.net> wrote: 

DP> Ted Zlatanov <tzz@lifelogs.com> writes:
>> On Fri, 04 Dec 2009 00:35:25 +1100 Daniel Pittman <daniel@rimspace.net> wrote:
>> 
DP> I have papers for Gnus, and Emacs, on file, although I don't consider the
DP> content original enough to warrant them: while it moves a whole bunch of
DP> lines, it just moves them.  Anyway, whatever.  I hope y'all accept it. :)
>> 
>> I think your version is much easier to read and understand.  I don't use
>> Sieve so I can't test it but otherwise I'm in favor of comitting your
>> patch.

DP> Well, the generated output is (trivially) identical to the original; it puts
DP> us in no worse a state than the previous code, but more fine-grained.

DP> Oh, and it actually generates a local file only; if you wish, you can test it
DP> through generating the content and observing the output. :)

I've been curious about Sieve but there's no info on using it with
Gnus.  Also I found Cyrus IMAP painful when I set it up and at the time
it was the only decent Sieve implementation.

Does anyone use it with dovecot (http://wiki.dovecot.org/LDA/Sieve)?  Do
we have ManageSieve support in Gnus, and if not, can it be added?

Ted

Re: gnus-sieve: make it easier to customize.

[Daniel Pittman]

Ted Zlatanov <tzz@lifelogs.com> writes:
> On Fri, 04 Dec 2009 12:46:37 +1100 Daniel Pittman <daniel@rimspace.net> wrote: 
> DP> Ted Zlatanov <tzz@lifelogs.com> writes:
>>> On Fri, 04 Dec 2009 00:35:25 +1100 Daniel Pittman <daniel@rimspace.net> wrote:
>>> 
> DP> I have papers for Gnus, and Emacs, on file, although I don't consider the
> DP> content original enough to warrant them: while it moves a whole bunch of
> DP> lines, it just moves them.  Anyway, whatever.  I hope y'all accept it. :)
>>> 
>>> I think your version is much easier to read and understand.  I don't use
>>> Sieve so I can't test it but otherwise I'm in favor of comitting your
>>> patch.
>
> DP> Well, the generated output is (trivially) identical to the original; it puts
> DP> us in no worse a state than the previous code, but more fine-grained.
>
> DP> Oh, and it actually generates a local file only; if you wish, you can test it
> DP> through generating the content and observing the output. :)
>
> I've been curious about Sieve but there's no info on using it with Gnus.

The Gnus manual, and the Gnus-Sieve manual, both in info format, don't do it
for you?  In fairness, I guess, they are "technical reference" guides to the
integration features, not anything user-focused about the Sieve language
itself.

The short version is, though, that you edit group properties to add a "sieve"
property resembling the expression to file messages into that group:

   INBOX/personal =>
   ((sieve address ["to" "cc"] "daniel@rimspace.net"))

> Also I found Cyrus IMAP painful when I set it up and at the time it was the
> only decent Sieve implementation.
>
> Does anyone use it with dovecot (http://wiki.dovecot.org/LDA/Sieve)?

No, but friends of mine support large numbers (> 10K) users in education using
it, and find it effective and worthwhile.  I use it with Zimbra, more or less.

> Do we have ManageSieve support in Gnus, and if not, can it be added?

Mostly outside it, but the facilities are there.  Read the Sieve manual
shipped with Emacs for details. :)

        Daniel
-- 
✣ Daniel Pittman            ✉ daniel@rimspace.net            ☎ +61 401 155 707
               ♽ made with 100 percent post-consumer electrons

Re: gnus-sieve: make it easier to customize.

[Ted Zlatanov]

On Sun, 13 Dec 2009 21:24:38 +1100 Daniel Pittman <daniel@rimspace.net> wrote: 

DP> Ted Zlatanov <tzz@lifelogs.com> writes:
>> I've been curious about Sieve but there's no info on using it with Gnus.

DP> The Gnus manual, and the Gnus-Sieve manual, both in info format, don't do it
DP> for you?  In fairness, I guess, they are "technical reference" guides to the
DP> integration features, not anything user-focused about the Sieve language
DP> itself.

Sorry, I meant to say there's no user-focused info on using it with Gnus
as you said.  I was not thinking when I wrote that.  

The information in both manuals is for those who already have Sieve set
up.  It's especially important to explain how Sieve works and how it's
different from client-side Gnus splitting, so maybe that requires a
separate section?

My eventual goal is to store the Gnus registry in a distributed way
(probably via imap-hash.el) and generate Sieve scripts from it to split
by sender, subject, or references.  I don't know if that's the right
approach but it seems most useful.

DP> The short version is, though, that you edit group properties to add a "sieve"
DP> property resembling the expression to file messages into that group:

DP>    INBOX/personal =>
DP>    ((sieve address ["to" "cc"] "daniel@rimspace.net"))

Thanks for explaining.  I saw the example in the "Sieve Commands" node
too.

The Gnus Sieve section points to a broken link
(http://www.gnu.org/software/emacs/manual/html_node/sieve/index.html#Top).
I think that's because the Emacs Sieve mode has its own manual.
http://www.emacswiki.org/emacs/SieveMode also has some good links.

>> Do we have ManageSieve support in Gnus, and if not, can it be added?

DP> Mostly outside it, but the facilities are there.  Read the Sieve manual
DP> shipped with Emacs for details. :)

Yeah, that seems sufficient.  It seems like there are only a few Sieve
Gnus users, though.  I wonder if it's worth supporting ManageSieve
explicitly in Gnus.  Maybe it's better to concentrate on generating the
rules on the server side from distributed rules, like the Gnus registry
I mentioned.

Ted