From owner-ietf-mta-filters Fri Jan 10 12:19:18 2003 Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0AKJIo20139 for ietf-mta-filters-bks; Fri, 10 Jan 2003 12:19:18 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0AKJFo20126 for ; Fri, 10 Jan 2003 12:19:15 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0AKJBk30328; Fri, 10 Jan 2003 21:19:11 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> From: Kjetil Torgrim Homme Date: 10 Jan 2003 21:19:11 +0100 In-Reply-To: <1radizcu9s.fsf@tolf.ifi.uio.no> Message-ID: <1rsmw0hi68.fsf@vingodur.ifi.uio.no> Lines: 11 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: --=-=-= I got some very good feedback from Jutta Degener, and so quite a bit has changed (for the better, I hope ;). comments are very welcome. --=-=-= Content-Disposition: attachment; filename=draft-homme-sieve-variables-01.txt Network Working Group K. T. Homme Document: draft-homme-sieve-variables-00.txt University of Oslo Expires July 10, 2003 10 Jan 2003 Sieve -- Variables Extension Status of this Memo This document is an Internet-Draft and is subject to all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Distribution of this memo is unlimited. Abstract In advanced filtering rule sets, it is useful to keep state or configuration details across rules. This extension adds an action to store data in variables, changes the interpolation of double quoted strings, and supplies a new test so that the value of a string can be examined. 0 Meta-information on this draft This information is intended to facilitate discussion. It will be removed when this document leaves the Internet-Draft stage. 0.1 Discussion This draft is intended to be an extension to the Sieve mail filtering language, available from the RFC repository as Homme [Page 1] Internet Draft Sieve -- Variables Extension 10 Jan 2003 . This draft and the Sieve language itself are being discussed on the MTA Filters mailing list at . Subscription requests can be sent to (send an email message with the word "subscribe" in the body). More information on the mailing list along with a WWW archive of back messages is available at . 0.2 Noted Changes a) We don't change the existing syntax, but modify the semantics of strings instead. b) Variable names are now case-insensitive. c) Previously reserved variable names are now initialised by the user through extra actions. d) Modifiers for the variable values have been added. The primary motivation for this is fileinto "INBOX.lists.${lower:listname}", where listname has been determined dynamically from the headers of the e-mail. 0.3 Open Issues a) Should we include more predefined variables to access the time? (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name of month, name of weekday, ...) Could use strftime(3c) as a list of what to offer, but the names should be in English. b) This extension is particularily useful if fileinto is extended to create new folders on demand. Example: setdate fileinto :makefolder "archive.${year}-${month}"; It is not clear if this feature should be included here or left for a separate extension. c) Should the modifier syntax be prefix or postfix? ${var.lower} may be more natural than ${lower:var}. d) Should references to unknown variables be left in place (rather than replaced by the empty string) to ease debugging scripts with typos? Homme [Page 2] Internet Draft Sieve -- Variables Extension 10 Jan 2003 1. Introduction This is an extension to the Sieve language defined by [SIEVE]. It adds support for storing and referencing data in string variables. Conventions for notations are as in [SIEVE] section 1.1, including use of [KEYWORDS]. 2. Capability Identifier The capability string associated with the extension defined in this document is "variables". 3. Interpretation of strings This extension changes the semantics of quoted-string, multi-line- literal and multi-line-dotstuff found in [SIEVE] to enable the inclusion of the value of variables. The syntax follows [ABNF]. variable-ref = "${" *variable-modifier variable-name "}" variable-modifier = 1*ALPHA ":" variable-name = num-variable / user-variable num-variable = 1*DIGIT user-variable = ALPHA *(ALPHA / DIGIT / "_") When the string is evaluated, substrings matching variable-ref shall be replaced by the value of variable-name. Variable names are case insensitive. Unknown variables are replaced by the empty string. As per the grammar, illegal variable names leaves the would-be variable- ref verbatim, since it doesn't match the variable-ref syntax. Examples: "&%${}!" => unchanged, as the empty string is an illegal identifier. "${doh!}" => unchanged, as "!" is illegal in identifiers. "${argggh}" => the empty string, if "argggh" is an unknown variable, or else the value of the variable. Strings SHOULD be evaluated every time control reaches the statement it is a part of, to make sure the expanded variable values are up-to- date. 3.1 Interaction with quoting The semantics of quoting using backslash are not changed. Backslash quoting is resolved before doing variable substitution. Homme [Page 3] Internet Draft Sieve -- Variables Extension 10 Jan 2003 Examples: "${fo\o}" => ${foo} => the expansion of variable foo. "${fo\\o}" => ${fo\o} => illegal identifier => left verbatim. "\${foo}" => ${foo} => the expansion of variable foo. "\\${foo}" => \${foo} => a backslash character followed by the expansion of variable foo. 3.2 Reserved variables 3.2.1 Numeric variables Unless the extension "regex" is in use, all variables whose names are all digits MUST evaluate to the empty string. The decimal value of the numeric variable name will index the list of matching strings from the each of the group operators in the latest regular expression match. The first pair of grouping parentheses has index 1. If the index is out of range, the empty string will be substituted. Index 0 returns the number of matching groups. Example: require [ "fileinto", "regex", "variables", "vacation" ]; if header :regex "List-ID" "<(.*)@" { fileinto "lists.${1}"; stop; } if header :regex "From" "^ set greeting "Dear ${1},"; } if header :regex "Subject" "(.*)" { set subject " on ${1}"; } vacation text: ${greeting} Thank you for your mail${subject}. I'm away from office for a few days, but I will get back to you as soon as possible. . ; 3.2.2 Dollar The value of ${dollar} is always "$". This means the literal value of "$" can be escaped by entering it as "${dollar}". Homme [Page 4] Internet Draft Sieve -- Variables Extension 10 Jan 2003 Example: "make ${dollar}${dollar}${dollar} fast" => "make $$$ fast" Note: it is not required to escape "$$$". 3.3 Modifiers Modifiers change the expansion of the variable. More than one can be specified, in which case they are applied from right to left. Modifier names are case insensitive. Unknown modifiers MUST yield a syntax error. Examples: set string "juMBlEd lETteRS" "${length:string}" => "15" "${lower:string}" => "jumbled letters" "${upperfirst:string}" => "JuMBlEd lETteRS" "${upperfirst:lower:string}" => "Jumbled letters" 3.3.1 Modifier "length:" The expansion of the variable is replaced by the length of the expansion. 3.3.2 Case modifiers These modifiers change the letters of the text from upper to lower case or vice versa. The implementation MUST support US-ASCII, but it's not required to handle the entire Unicode repertoire. 3.3.2.1 Modifier "upper:" All lower case letters are converted to their upper case counterpart. 3.3.2.2 Modifier "lower:" All upper case letters are converted to their lower case counterpart. 3.3.2.3 Modifier "upperfirst:" The first character of the expansion is converted to upper case if it is lower case. The rest of the expansion is left unchanged. 3.3.2.4 Modifier "lowerfirst:" The first character of the expansion is converted to lower case if it is upper case. The rest of the expansion is left unchanged. Homme [Page 5] Internet Draft Sieve -- Variables Extension 10 Jan 2003 4. Action set Syntax: set The "set" action stores the specified value in the variable. Assignment to a reserved variable name or an illegal identifier MUST cause a syntax error. All variables have global scope. Variable names are case insensitive. Example: set honorific "Mr"; set first_name "Wile"; set last_name "Coyote"; set vacation text: Dear ${HONORIFIC} ${last_name}, I'm out, please leave a message after the meep. . ; "set" does not affect the implicit keep. 5. Action setdate the action setdate initialises a few variables: ${year} => the current year, "0000" .. "9999" ${month} => the current month, "01" .. "12" ${day} => the current day, "01" .. "31" ${hour} => the current hour, "00" .. "23" ${minute} => the current hour, "00" .. "59" ${second} => the current second, "00" .. "59" These variables SHOULD reference the time when execution of the Sieve script reaches the statement. The local timezone SHOULD be used. 6. Test string Syntax: string [MATCH-TYPE] [COMPARATOR] The "string" test evaluates to true if any of the strings matches any key. The type of match defaults to ":is". 7. Security Considerations When combined with the regex extension, strings can contain arbitrary values controlled by the sender of the e-mail if the author of the Homme [Page 6] Internet Draft Sieve -- Variables Extension 10 Jan 2003 script isn't careful. The introduction of variables makes advanced decision making easier to write, but since no looping construct is provided, all Sieve scripts will terminate orderly. 8. Acknowledgments Thanks to Peder Stray for inspiration, and Jutta Degener for valuable feedback. 8. Author's Address Kjetil T. Homme Frydens g 5B 0564 Oslo, Norway Phone: +47 9366 0091 E-mail: kjetilho@ifi.uio.no Appendix A. References [ABNF] D. Crocker, Ed., "Augmented BNF for Syntax Specifications: ABNF", Internet Mail Consortium, RFC 2234, November 1997 [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", Harvard University, RFC 2119, March 1997. [SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", Mirapoint, RFC 3028, January 2001. Appendix B. Full Copyright Statement Copyright (C) The Internet Society 2002. All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of develop- ing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. Homme [Page 7] Internet Draft Sieve -- Variables Extension 10 Jan 2003 The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Homme [Page 8] --=-=-= (the new draft has been submitted to IETF.) -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html --=-=-=-- From owner-ietf-mta-filters Mon Jan 13 16:24:40 2003 Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E0Oe327117 for ietf-mta-filters-bks; Mon, 13 Jan 2003 16:24:40 -0800 (PST) Received: from starship.enterprise.ucs.ed.ac.uk (starship.enterprise.ucs.ed.ac.uk [129.215.40.70]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E0Oco27113 for ; Mon, 13 Jan 2003 16:24:38 -0800 (PST) Received: from nigelhome (pc-80-195-5-134-ed.blueyonder.co.uk [80.195.5.134]) by enterprise.ucs.ed.ac.uk (Rockliffe SMTPRA 5.2.3) with ESMTP id ; Tue, 14 Jan 2003 00:24:40 +0000 Message-ID: <01bd01c2bb63$63bc33b0$8605c350@nigelhome> From: "Nigel Swinson" To: , "Kjetil Torgrim Homme" References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> Subject: Re: dynamic naming & creation of mailboxes Date: Tue, 14 Jan 2003 00:25:06 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: > I got some very good feedback from Jutta Degener, and so quite a bit > has changed (for the better, I hope ;). comments are very welcome. Hiya, 5. Action setdate These variables SHOULD reference the time when execution of the Sieve script reaches the statement. The local timezone SHOULD be used. The local timezone is going to be the timezone of the server, which may not be the "local" timezone for the user. I would suggest that this be a UTC time, as then there will only be one time conversion to do, rather than potentially two. ie I check my mail from the US East coast, the server is US West coast. "localtime" US West coast isn't so useful to me. Also part of the point of Sieve is that your filter will do the same thing on any server. So if you import your script into a different mailbox, that runs on a server in a different timezone, then you will have to modify the times in the sieve script. And then what if you run an ISP with mailservers in several timezones. If the script uses the local timezone, then this means that you can't move users to different timezones without modifying their sieve script. a) Should we include more predefined variables to access the time? (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name of month, name of weekday, ...) Could use strftime(3c) as a list of what to offer, but the names should be in English. Don't really follow why we need ${dollar} at all. Most of the time $ won't be followed by { and if we want it to then \${ or $\{ will escape it for us. Incidentally how should we behave if the "}" is missing? Presumably treating it as illegal. Perhaps there should be an example about this... hour, minutes, name etc are probably more useful predefined variables than the dollar, and mean you don't have to call setdate. In fact given how cheap it is to do a "set date" action, it might actually be better to just do the setdate in a lazy fashion, when a reference to a time is requested, rather than have to bother calling setdate. b) This extension is particularily useful if fileinto is extended to create new folders on demand. Example: setdate fileinto :makefolder "archive.${year}-${month}"; It is not clear if this feature should be included here or left for a separate extension. Separate extension. c) Should the modifier syntax be prefix or postfix? ${var.lower} may be more natural than ${lower:var}. Prefix. More "function call" like d) Should references to unknown variables be left in place (rather than replaced by the empty string) to ease debugging scripts with typos? Set to null, as perhaps a "set =" is only executed in one of the if blocks, so it's not an "error" that needs debugged if we didn't go through the if. Cheers Nigel From owner-ietf-mta-filters Mon Jan 13 19:00:55 2003 Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E30tQ01227 for ietf-mta-filters-bks; Mon, 13 Jan 2003 19:00:55 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E30qo01220 for ; Mon, 13 Jan 2003 19:00:52 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0E30oS01523; Tue, 14 Jan 2003 04:00:50 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: ietf-mta-filters@imc.org Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> From: Kjetil Torgrim Homme Date: 14 Jan 2003 04:00:50 +0100 In-Reply-To: <01bd01c2bb63$63bc33b0$8605c350@nigelhome> Message-ID: <1r65sscu59.fsf@vingodur.ifi.uio.no> Lines: 146 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: [Nigel Swinson]: > > 5. Action setdate > > > > These variables SHOULD reference the time when execution of the > Sieve script reaches the statement. The local timezone SHOULD > be used. > > The local timezone is going to be the timezone of the server, > which may not be the "local" timezone for the user. I would > suggest that this be a UTC time, as then there will only be one > time conversion to do, rather than potentially two. ie I check my > mail from the US East coast, the server is US West coast. > "localtime" US West coast isn't so useful to me. heh, yeah. I guess this is different for people in the US and other large countries which span several timezones. however, I think it will be confusing and annoying for users to have their mail archive switch to a new folder seven hours before midnight. perhaps allow the user to specify timezone explicitly? but then there's the issue of daylight savings time. ugh. AFAIK, there is no IANA registry for timezone information. we could use POSIX syntax, but it's pretty cryptic, e.g., in Central Europe the correct value is "MET1METDST2,M3.5.0,M10.5.0". this is OK if your OS supports it, but I'd hate to write the code myself! how about adding an optional argument of the form +HHMM or -HHMM, and punt on the daylight savings issue. if the argument is left out, use localtime. this way small ISPs, universities etc. can offer the "natural" behaviour without requiring their users to jump through hoops. if you want UTC, use setdate +0000. > Also part of the point of Sieve is that your filter will do the > same thing on any server. is that a requirement, or just a Good Thing? > And then what if you run an ISP with mailservers in several > timezones. If the script uses the local timezone, then this means > that you can't move users to different timezones without modifying > their sieve script. that was the reason for SHOULD. a multinational ISP would probably use UTC. > a) Should we include more predefined variables to access the time? > (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name > of month, name of weekday, ...) Could use strftime(3c) as a list of > what to offer, but the names should be in English. > > Don't really follow why we need ${dollar} at all. Most of the > time $ won't be followed by { true. I included it to have a simple way to quote arbitrary text for inclusion in a script without parsing them, like s,\$,\${dollar},g > and if we want it to then \${ or $\{ will escape it for us. no, it won't. backslashes are resolved before variables are substituted. I didn't want to change that part of the original Sieve specification. but, the user can actually set dollar "$" set text "regarding ${dollar}{dollar}" if the need arises. so it is really superfluous. I'll fix the draft, thanks! > Incidentally how should we behave if the "}" is missing? > Presumably treating it as illegal. Perhaps there should be an > example about this... yes. the parser should terminate its search for } as soon as an illegal character has been found [^a-z0-9_] (most likely a space character), and copy the syntax error(?) verbatim. set var "something" set text "hi ${junk ${var}}" text now holds the value "hi ${junk something}". > hour, minutes, name etc are probably more useful predefined > variables than the dollar, and mean you don't have to call > setdate. my first version of the draft had them as builtins. I used case-sensitivity to mark them as reserved names (if the first letter was uppercase, assignment was illegal). but case sensitivity is a bad idea, and I think it is cleaner to have no magic reserved words, unless the user explicitly asks for them. it also allows the user to influence the values, cf. timezone discussion above. > In fact given how cheap it is to do a "set date" action, it might > actually be better to just do the setdate in a lazy fashion, when > a reference to a time is requested, rather than have to bother > calling setdate. it is important not to be too lazy. you want all the time variables to be set at the same time, or else you risk mail falling between cracks. if string "${hour}" "00" { } else if string "${hour}" "23" { } if the mail arrives at just before midnight, the first test fails. then the clock ticks, and the second test fails also. (with setdate, the user is allowed to shoot himself in the foot.) > fileinto :makefolder "archive.${year}-${month}"; > > It is not clear if this feature should be included here or left > for a separate extension. > > Separate extension. ok. I agree, it just that it's such a tiny extension :-) > c) Should the modifier syntax be prefix or postfix? ${var.lower} may > be more natural than ${lower:var}. > > Prefix. More "function call" like yeah. to clarify "more natural": I used prefix since that is what I'm used to from bash programming (which has horrific syntax, btw :), but thought of postfix when I had to write that the modifiers are applied right to left (which is the natural way of doing it). with postfix, the order of the modifiers matches the syntax. > d) Should references to unknown variables be left in place (rather > than replaced by the empty string) to ease debugging scripts with > typos? > > Set to null, as perhaps a "set =" is only executed in one of the > if blocks, so it's not an "error" that needs debugged if we didn't > go through the if. > Cheers thank you for your feedback! -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html From owner-ietf-mta-filters Tue Jan 14 01:30:22 2003 Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E9UMr04523 for ietf-mta-filters-bks; Tue, 14 Jan 2003 01:30:22 -0800 (PST) Received: from bra.gulbrandsen.priv.no (bra.gulbrandsen.priv.no [212.125.101.197]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E9UIo04518 for ; Tue, 14 Jan 2003 01:30:19 -0800 (PST) Received: from melkebalanse.gulbrandsen.priv.no ([217.19.171.131]:20426 "ehlo melkebalanse.gulbrandsen.priv.no") by gulbrandsen.priv.no with ESMTP id ; Tue, 14 Jan 2003 10:30:07 +0100 Message-Id: From: Arnt Gulbrandsen To: Kjetil Torgrim Homme Subject: Re: dynamic naming & creation of mailboxes Cc: ietf-mta-filters@imc.org References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> <1r65sscu59.fsf@vingodur.ifi.uio.no> In-Reply-To: <1r65sscu59.fsf@vingodur.ifi.uio.no> Content-Type: text/plain; format=flowed MIME-Version: 1.0 Date: Tue, 14 Jan 2003 10:32:00 +0100 Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: Kjetil Torgrim Homme writes: > heh, yeah. I guess this is different for people in the US and other > large countries which span several timezones. It's a company thing, not a country thing. I knew people working in Dublin whose servers were somewhere on the West Coast. They complained about slow connections and so on - timezone seemed a minor issue ;) > however, I think it will be confusing and annoying for users to have > their mail archive switch to a new folder seven hours before > midnight. perhaps allow the user to specify timezone explicitly? Simplicity is better. Most people leave work in the afternoon and arrive in the morning. The folder will have switched sometime during the interval. Does the exact time really matter? The IMAP users in Petrapavlovsk and those of us who regularly work near midnight might have a problem, but after the first couple of months, we learn. The broken threads caused by the change is a much worse problem. --Arnt From owner-ietf-mta-filters Tue Jan 14 06:46:56 2003 Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0EEku423172 for ietf-mta-filters-bks; Tue, 14 Jan 2003 06:46:56 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0EEkto23167 for ; Tue, 14 Jan 2003 06:46:55 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0EEkor13239; Tue, 14 Jan 2003 15:46:50 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: ietf-mta-filters@imc.org Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> <1r65sscu59.fsf@vingodur.ifi.uio.no> From: Kjetil Torgrim Homme Date: 14 Jan 2003 15:46:50 +0100 In-Reply-To: Message-ID: <1r65sraiw5.fsf@vingodur.ifi.uio.no> Lines: 26 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: [Arnt Gulbrandsen]: > > Kjetil Torgrim Homme writes: > > however, I think it will be confusing and annoying for users to > > have their mail archive switch to a new folder seven hours > > before midnight. perhaps allow the user to specify timezone > > explicitly? > > Simplicity is better. > > Most people leave work in the afternoon and arrive in the > morning. The folder will have switched sometime during the > interval. Does the exact time really matter? and people in New Zealand? as a user, I would complain loudly about the broken mail server which didn't even keep a useful time. when I ask for ${hour}, I (still as a naive user) would expect it to return my local time. never mind that the server has no way of knowing your local time... that's why I think the principle of least surprise is to use the server's timezone. anyway, SETDATE is tangential to the proposal, and can be left out. -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0EEku423172 for ietf-mta-filters-bks; Tue, 14 Jan 2003 06:46:56 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0EEkto23167 for ; Tue, 14 Jan 2003 06:46:55 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0EEkor13239; Tue, 14 Jan 2003 15:46:50 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: ietf-mta-filters@imc.org Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> <1r65sscu59.fsf@vingodur.ifi.uio.no> From: Kjetil Torgrim Homme Date: 14 Jan 2003 15:46:50 +0100 In-Reply-To: Message-ID: <1r65sraiw5.fsf@vingodur.ifi.uio.no> Lines: 26 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: [Arnt Gulbrandsen]: > > Kjetil Torgrim Homme writes: > > however, I think it will be confusing and annoying for users to > > have their mail archive switch to a new folder seven hours > > before midnight. perhaps allow the user to specify timezone > > explicitly? > > Simplicity is better. > > Most people leave work in the afternoon and arrive in the > morning. The folder will have switched sometime during the > interval. Does the exact time really matter? and people in New Zealand? as a user, I would complain loudly about the broken mail server which didn't even keep a useful time. when I ask for ${hour}, I (still as a naive user) would expect it to return my local time. never mind that the server has no way of knowing your local time... that's why I think the principle of least surprise is to use the server's timezone. anyway, SETDATE is tangential to the proposal, and can be left out. -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E9UMr04523 for ietf-mta-filters-bks; Tue, 14 Jan 2003 01:30:22 -0800 (PST) Received: from bra.gulbrandsen.priv.no (bra.gulbrandsen.priv.no [212.125.101.197]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E9UIo04518 for ; Tue, 14 Jan 2003 01:30:19 -0800 (PST) Received: from melkebalanse.gulbrandsen.priv.no ([217.19.171.131]:20426 "ehlo melkebalanse.gulbrandsen.priv.no") by gulbrandsen.priv.no with ESMTP id ; Tue, 14 Jan 2003 10:30:07 +0100 Message-Id: From: Arnt Gulbrandsen To: Kjetil Torgrim Homme Subject: Re: dynamic naming & creation of mailboxes Cc: ietf-mta-filters@imc.org References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> <1r65sscu59.fsf@vingodur.ifi.uio.no> In-Reply-To: <1r65sscu59.fsf@vingodur.ifi.uio.no> Content-Type: text/plain; format=flowed MIME-Version: 1.0 Date: Tue, 14 Jan 2003 10:32:00 +0100 Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: Kjetil Torgrim Homme writes: > heh, yeah. I guess this is different for people in the US and other > large countries which span several timezones. It's a company thing, not a country thing. I knew people working in Dublin whose servers were somewhere on the West Coast. They complained about slow connections and so on - timezone seemed a minor issue ;) > however, I think it will be confusing and annoying for users to have > their mail archive switch to a new folder seven hours before > midnight. perhaps allow the user to specify timezone explicitly? Simplicity is better. Most people leave work in the afternoon and arrive in the morning. The folder will have switched sometime during the interval. Does the exact time really matter? The IMAP users in Petrapavlovsk and those of us who regularly work near midnight might have a problem, but after the first couple of months, we learn. The broken threads caused by the change is a much worse problem. --Arnt Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E30tQ01227 for ietf-mta-filters-bks; Mon, 13 Jan 2003 19:00:55 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E30qo01220 for ; Mon, 13 Jan 2003 19:00:52 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0E30oS01523; Tue, 14 Jan 2003 04:00:50 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: ietf-mta-filters@imc.org Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> <01bd01c2bb63$63bc33b0$8605c350@nigelhome> From: Kjetil Torgrim Homme Date: 14 Jan 2003 04:00:50 +0100 In-Reply-To: <01bd01c2bb63$63bc33b0$8605c350@nigelhome> Message-ID: <1r65sscu59.fsf@vingodur.ifi.uio.no> Lines: 146 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: [Nigel Swinson]: > > 5. Action setdate > > > > These variables SHOULD reference the time when execution of the > Sieve script reaches the statement. The local timezone SHOULD > be used. > > The local timezone is going to be the timezone of the server, > which may not be the "local" timezone for the user. I would > suggest that this be a UTC time, as then there will only be one > time conversion to do, rather than potentially two. ie I check my > mail from the US East coast, the server is US West coast. > "localtime" US West coast isn't so useful to me. heh, yeah. I guess this is different for people in the US and other large countries which span several timezones. however, I think it will be confusing and annoying for users to have their mail archive switch to a new folder seven hours before midnight. perhaps allow the user to specify timezone explicitly? but then there's the issue of daylight savings time. ugh. AFAIK, there is no IANA registry for timezone information. we could use POSIX syntax, but it's pretty cryptic, e.g., in Central Europe the correct value is "MET1METDST2,M3.5.0,M10.5.0". this is OK if your OS supports it, but I'd hate to write the code myself! how about adding an optional argument of the form +HHMM or -HHMM, and punt on the daylight savings issue. if the argument is left out, use localtime. this way small ISPs, universities etc. can offer the "natural" behaviour without requiring their users to jump through hoops. if you want UTC, use setdate +0000. > Also part of the point of Sieve is that your filter will do the > same thing on any server. is that a requirement, or just a Good Thing? > And then what if you run an ISP with mailservers in several > timezones. If the script uses the local timezone, then this means > that you can't move users to different timezones without modifying > their sieve script. that was the reason for SHOULD. a multinational ISP would probably use UTC. > a) Should we include more predefined variables to access the time? > (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name > of month, name of weekday, ...) Could use strftime(3c) as a list of > what to offer, but the names should be in English. > > Don't really follow why we need ${dollar} at all. Most of the > time $ won't be followed by { true. I included it to have a simple way to quote arbitrary text for inclusion in a script without parsing them, like s,\$,\${dollar},g > and if we want it to then \${ or $\{ will escape it for us. no, it won't. backslashes are resolved before variables are substituted. I didn't want to change that part of the original Sieve specification. but, the user can actually set dollar "$" set text "regarding ${dollar}{dollar}" if the need arises. so it is really superfluous. I'll fix the draft, thanks! > Incidentally how should we behave if the "}" is missing? > Presumably treating it as illegal. Perhaps there should be an > example about this... yes. the parser should terminate its search for } as soon as an illegal character has been found [^a-z0-9_] (most likely a space character), and copy the syntax error(?) verbatim. set var "something" set text "hi ${junk ${var}}" text now holds the value "hi ${junk something}". > hour, minutes, name etc are probably more useful predefined > variables than the dollar, and mean you don't have to call > setdate. my first version of the draft had them as builtins. I used case-sensitivity to mark them as reserved names (if the first letter was uppercase, assignment was illegal). but case sensitivity is a bad idea, and I think it is cleaner to have no magic reserved words, unless the user explicitly asks for them. it also allows the user to influence the values, cf. timezone discussion above. > In fact given how cheap it is to do a "set date" action, it might > actually be better to just do the setdate in a lazy fashion, when > a reference to a time is requested, rather than have to bother > calling setdate. it is important not to be too lazy. you want all the time variables to be set at the same time, or else you risk mail falling between cracks. if string "${hour}" "00" { } else if string "${hour}" "23" { } if the mail arrives at just before midnight, the first test fails. then the clock ticks, and the second test fails also. (with setdate, the user is allowed to shoot himself in the foot.) > fileinto :makefolder "archive.${year}-${month}"; > > It is not clear if this feature should be included here or left > for a separate extension. > > Separate extension. ok. I agree, it just that it's such a tiny extension :-) > c) Should the modifier syntax be prefix or postfix? ${var.lower} may > be more natural than ${lower:var}. > > Prefix. More "function call" like yeah. to clarify "more natural": I used prefix since that is what I'm used to from bash programming (which has horrific syntax, btw :), but thought of postfix when I had to write that the modifiers are applied right to left (which is the natural way of doing it). with postfix, the order of the modifiers matches the syntax. > d) Should references to unknown variables be left in place (rather > than replaced by the empty string) to ease debugging scripts with > typos? > > Set to null, as perhaps a "set =" is only executed in one of the > if blocks, so it's not an "error" that needs debugged if we didn't > go through the if. > Cheers thank you for your feedback! -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0E0Oe327117 for ietf-mta-filters-bks; Mon, 13 Jan 2003 16:24:40 -0800 (PST) Received: from starship.enterprise.ucs.ed.ac.uk (starship.enterprise.ucs.ed.ac.uk [129.215.40.70]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0E0Oco27113 for ; Mon, 13 Jan 2003 16:24:38 -0800 (PST) Received: from nigelhome (pc-80-195-5-134-ed.blueyonder.co.uk [80.195.5.134]) by enterprise.ucs.ed.ac.uk (Rockliffe SMTPRA 5.2.3) with ESMTP id ; Tue, 14 Jan 2003 00:24:40 +0000 Message-ID: <01bd01c2bb63$63bc33b0$8605c350@nigelhome> From: "Nigel Swinson" To: , "Kjetil Torgrim Homme" References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> <1rsmw0hi68.fsf@vingodur.ifi.uio.no> Subject: Re: dynamic naming & creation of mailboxes Date: Tue, 14 Jan 2003 00:25:06 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: > I got some very good feedback from Jutta Degener, and so quite a bit > has changed (for the better, I hope ;). comments are very welcome. Hiya, 5. Action setdate These variables SHOULD reference the time when execution of the Sieve script reaches the statement. The local timezone SHOULD be used. The local timezone is going to be the timezone of the server, which may not be the "local" timezone for the user. I would suggest that this be a UTC time, as then there will only be one time conversion to do, rather than potentially two. ie I check my mail from the US East coast, the server is US West coast. "localtime" US West coast isn't so useful to me. Also part of the point of Sieve is that your filter will do the same thing on any server. So if you import your script into a different mailbox, that runs on a server in a different timezone, then you will have to modify the times in the sieve script. And then what if you run an ISP with mailservers in several timezones. If the script uses the local timezone, then this means that you can't move users to different timezones without modifying their sieve script. a) Should we include more predefined variables to access the time? (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name of month, name of weekday, ...) Could use strftime(3c) as a list of what to offer, but the names should be in English. Don't really follow why we need ${dollar} at all. Most of the time $ won't be followed by { and if we want it to then \${ or $\{ will escape it for us. Incidentally how should we behave if the "}" is missing? Presumably treating it as illegal. Perhaps there should be an example about this... hour, minutes, name etc are probably more useful predefined variables than the dollar, and mean you don't have to call setdate. In fact given how cheap it is to do a "set date" action, it might actually be better to just do the setdate in a lazy fashion, when a reference to a time is requested, rather than have to bother calling setdate. b) This extension is particularily useful if fileinto is extended to create new folders on demand. Example: setdate fileinto :makefolder "archive.${year}-${month}"; It is not clear if this feature should be included here or left for a separate extension. Separate extension. c) Should the modifier syntax be prefix or postfix? ${var.lower} may be more natural than ${lower:var}. Prefix. More "function call" like d) Should references to unknown variables be left in place (rather than replaced by the empty string) to ease debugging scripts with typos? Set to null, as perhaps a "set =" is only executed in one of the if blocks, so it's not an "error" that needs debugged if we didn't go through the if. Cheers Nigel Received: (from majordomo@localhost) by above.proper.com (8.11.6/8.11.3) id h0AKJIo20139 for ietf-mta-filters-bks; Fri, 10 Jan 2003 12:19:18 -0800 (PST) Received: from vingodur.ifi.uio.no (vingodur.ifi.uio.no [129.240.68.200]) by above.proper.com (8.11.6/8.11.3) with ESMTP id h0AKJFo20126 for ; Fri, 10 Jan 2003 12:19:15 -0800 (PST) Received: (from kjetilho@localhost) by vingodur.ifi.uio.no (8.11.6/8.11.6) id h0AKJBk30328; Fri, 10 Jan 2003 21:19:11 +0100 X-Authentication-Warning: vingodur.ifi.uio.no: kjetilho set sender to kjetilho@ifi.uio.no using -f To: Subject: Re: dynamic naming & creation of mailboxes References: <1rznr5k0w8.fsf@vingodur.ifi.uio.no> <1radizcu9s.fsf@tolf.ifi.uio.no> From: Kjetil Torgrim Homme Date: 10 Jan 2003 21:19:11 +0100 In-Reply-To: <1radizcu9s.fsf@tolf.ifi.uio.no> Message-ID: <1rsmw0hi68.fsf@vingodur.ifi.uio.no> Lines: 11 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: owner-ietf-mta-filters@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: --=-=-= I got some very good feedback from Jutta Degener, and so quite a bit has changed (for the better, I hope ;). comments are very welcome. --=-=-= Content-Disposition: attachment; filename=draft-homme-sieve-variables-01.txt Network Working Group K. T. Homme Document: draft-homme-sieve-variables-00.txt University of Oslo Expires July 10, 2003 10 Jan 2003 Sieve -- Variables Extension Status of this Memo This document is an Internet-Draft and is subject to all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Distribution of this memo is unlimited. Abstract In advanced filtering rule sets, it is useful to keep state or configuration details across rules. This extension adds an action to store data in variables, changes the interpolation of double quoted strings, and supplies a new test so that the value of a string can be examined. 0 Meta-information on this draft This information is intended to facilitate discussion. It will be removed when this document leaves the Internet-Draft stage. 0.1 Discussion This draft is intended to be an extension to the Sieve mail filtering language, available from the RFC repository as Homme [Page 1] Internet Draft Sieve -- Variables Extension 10 Jan 2003 . This draft and the Sieve language itself are being discussed on the MTA Filters mailing list at . Subscription requests can be sent to (send an email message with the word "subscribe" in the body). More information on the mailing list along with a WWW archive of back messages is available at . 0.2 Noted Changes a) We don't change the existing syntax, but modify the semantics of strings instead. b) Variable names are now case-insensitive. c) Previously reserved variable names are now initialised by the user through extra actions. d) Modifiers for the variable values have been added. The primary motivation for this is fileinto "INBOX.lists.${lower:listname}", where listname has been determined dynamically from the headers of the e-mail. 0.3 Open Issues a) Should we include more predefined variables to access the time? (hour, minutes, timezone, weekday, week number (US, EU og ISO?), name of month, name of weekday, ...) Could use strftime(3c) as a list of what to offer, but the names should be in English. b) This extension is particularily useful if fileinto is extended to create new folders on demand. Example: setdate fileinto :makefolder "archive.${year}-${month}"; It is not clear if this feature should be included here or left for a separate extension. c) Should the modifier syntax be prefix or postfix? ${var.lower} may be more natural than ${lower:var}. d) Should references to unknown variables be left in place (rather than replaced by the empty string) to ease debugging scripts with typos? Homme [Page 2] Internet Draft Sieve -- Variables Extension 10 Jan 2003 1. Introduction This is an extension to the Sieve language defined by [SIEVE]. It adds support for storing and referencing data in string variables. Conventions for notations are as in [SIEVE] section 1.1, including use of [KEYWORDS]. 2. Capability Identifier The capability string associated with the extension defined in this document is "variables". 3. Interpretation of strings This extension changes the semantics of quoted-string, multi-line- literal and multi-line-dotstuff found in [SIEVE] to enable the inclusion of the value of variables. The syntax follows [ABNF]. variable-ref = "${" *variable-modifier variable-name "}" variable-modifier = 1*ALPHA ":" variable-name = num-variable / user-variable num-variable = 1*DIGIT user-variable = ALPHA *(ALPHA / DIGIT / "_") When the string is evaluated, substrings matching variable-ref shall be replaced by the value of variable-name. Variable names are case insensitive. Unknown variables are replaced by the empty string. As per the grammar, illegal variable names leaves the would-be variable- ref verbatim, since it doesn't match the variable-ref syntax. Examples: "&%${}!" => unchanged, as the empty string is an illegal identifier. "${doh!}" => unchanged, as "!" is illegal in identifiers. "${argggh}" => the empty string, if "argggh" is an unknown variable, or else the value of the variable. Strings SHOULD be evaluated every time control reaches the statement it is a part of, to make sure the expanded variable values are up-to- date. 3.1 Interaction with quoting The semantics of quoting using backslash are not changed. Backslash quoting is resolved before doing variable substitution. Homme [Page 3] Internet Draft Sieve -- Variables Extension 10 Jan 2003 Examples: "${fo\o}" => ${foo} => the expansion of variable foo. "${fo\\o}" => ${fo\o} => illegal identifier => left verbatim. "\${foo}" => ${foo} => the expansion of variable foo. "\\${foo}" => \${foo} => a backslash character followed by the expansion of variable foo. 3.2 Reserved variables 3.2.1 Numeric variables Unless the extension "regex" is in use, all variables whose names are all digits MUST evaluate to the empty string. The decimal value of the numeric variable name will index the list of matching strings from the each of the group operators in the latest regular expression match. The first pair of grouping parentheses has index 1. If the index is out of range, the empty string will be substituted. Index 0 returns the number of matching groups. Example: require [ "fileinto", "regex", "variables", "vacation" ]; if header :regex "List-ID" "<(.*)@" { fileinto "lists.${1}"; stop; } if header :regex "From" "^ set greeting "Dear ${1},"; } if header :regex "Subject" "(.*)" { set subject " on ${1}"; } vacation text: ${greeting} Thank you for your mail${subject}. I'm away from office for a few days, but I will get back to you as soon as possible. . ; 3.2.2 Dollar The value of ${dollar} is always "$". This means the literal value of "$" can be escaped by entering it as "${dollar}". Homme [Page 4] Internet Draft Sieve -- Variables Extension 10 Jan 2003 Example: "make ${dollar}${dollar}${dollar} fast" => "make $$$ fast" Note: it is not required to escape "$$$". 3.3 Modifiers Modifiers change the expansion of the variable. More than one can be specified, in which case they are applied from right to left. Modifier names are case insensitive. Unknown modifiers MUST yield a syntax error. Examples: set string "juMBlEd lETteRS" "${length:string}" => "15" "${lower:string}" => "jumbled letters" "${upperfirst:string}" => "JuMBlEd lETteRS" "${upperfirst:lower:string}" => "Jumbled letters" 3.3.1 Modifier "length:" The expansion of the variable is replaced by the length of the expansion. 3.3.2 Case modifiers These modifiers change the letters of the text from upper to lower case or vice versa. The implementation MUST support US-ASCII, but it's not required to handle the entire Unicode repertoire. 3.3.2.1 Modifier "upper:" All lower case letters are converted to their upper case counterpart. 3.3.2.2 Modifier "lower:" All upper case letters are converted to their lower case counterpart. 3.3.2.3 Modifier "upperfirst:" The first character of the expansion is converted to upper case if it is lower case. The rest of the expansion is left unchanged. 3.3.2.4 Modifier "lowerfirst:" The first character of the expansion is converted to lower case if it is upper case. The rest of the expansion is left unchanged. Homme [Page 5] Internet Draft Sieve -- Variables Extension 10 Jan 2003 4. Action set Syntax: set The "set" action stores the specified value in the variable. Assignment to a reserved variable name or an illegal identifier MUST cause a syntax error. All variables have global scope. Variable names are case insensitive. Example: set honorific "Mr"; set first_name "Wile"; set last_name "Coyote"; set vacation text: Dear ${HONORIFIC} ${last_name}, I'm out, please leave a message after the meep. . ; "set" does not affect the implicit keep. 5. Action setdate the action setdate initialises a few variables: ${year} => the current year, "0000" .. "9999" ${month} => the current month, "01" .. "12" ${day} => the current day, "01" .. "31" ${hour} => the current hour, "00" .. "23" ${minute} => the current hour, "00" .. "59" ${second} => the current second, "00" .. "59" These variables SHOULD reference the time when execution of the Sieve script reaches the statement. The local timezone SHOULD be used. 6. Test string Syntax: string [MATCH-TYPE] [COMPARATOR] The "string" test evaluates to true if any of the strings matches any key. The type of match defaults to ":is". 7. Security Considerations When combined with the regex extension, strings can contain arbitrary values controlled by the sender of the e-mail if the author of the Homme [Page 6] Internet Draft Sieve -- Variables Extension 10 Jan 2003 script isn't careful. The introduction of variables makes advanced decision making easier to write, but since no looping construct is provided, all Sieve scripts will terminate orderly. 8. Acknowledgments Thanks to Peder Stray for inspiration, and Jutta Degener for valuable feedback. 8. Author's Address Kjetil T. Homme Frydens g 5B 0564 Oslo, Norway Phone: +47 9366 0091 E-mail: kjetilho@ifi.uio.no Appendix A. References [ABNF] D. Crocker, Ed., "Augmented BNF for Syntax Specifications: ABNF", Internet Mail Consortium, RFC 2234, November 1997 [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", Harvard University, RFC 2119, March 1997. [SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", Mirapoint, RFC 3028, January 2001. Appendix B. Full Copyright Statement Copyright (C) The Internet Society 2002. All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of develop- ing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. Homme [Page 7] Internet Draft Sieve -- Variables Extension 10 Jan 2003 The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Homme [Page 8] --=-=-= (the new draft has been submitted to IETF.) -- Kjetil T. | read and make up your own mind | http://www.cactus48.com/truth.html --=-=-=--