draft-ietf-sieve-mime-loop-04.txt   draft-ietf-sieve-mime-loop-05.txt 
Internet Engineering Task Force T. Hansen Internet Engineering Task Force T. Hansen
Internet-Draft AT&T Laboratories Internet-Draft AT&T Laboratories
Intended status: Standards Track C. Daboo Intended status: Standards Track C. Daboo
Expires: August 26, 2008 Apple Inc. Expires: January 15, 2009 Apple Inc.
February 23, 2008 July 14, 2008
Sieve Email Filtering: MIME part Tests, Iteration, Extraction, Sieve Email Filtering: MIME part Tests, Iteration, Extraction,
Replacement and Enclosure Replacement and Enclosure
draft-ietf-sieve-mime-loop-04 draft-ietf-sieve-mime-loop-05
Status of this Memo Status of this Memo
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have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
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This Internet-Draft will expire on August 26, 2008. This Internet-Draft will expire on January 15, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document defines extensions to the Sieve email filtering This document defines extensions to the Sieve email filtering
language to permit analysis and manipulation of the MIME body parts language to permit analysis and manipulation of the MIME body parts
of an email message. of an email message.
Note Note
This document is being discussed on the MTA-FILTERS mailing list, This document is being discussed on the MTA-FILTERS mailing list,
ietf-mta-filters@imc.org. ietf-mta-filters@imc.org.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Sieve Loops . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Sieve Loops: Actions "foreverypart" and "break" . . . . . . . 3
4. Changes to Sieve tests . . . . . . . . . . . . . . . . . . . . 4 4. Changes to Sieve Tests . . . . . . . . . . . . . . . . . . . . 4
4.1. Test "header" . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Test "header" . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Test "address" . . . . . . . . . . . . . . . . . . . . . . 6 4.2. Test "address" . . . . . . . . . . . . . . . . . . . . . 6
4.3. Test "exists" . . . . . . . . . . . . . . . . . . . . . . 7 4.3. Test "exists" . . . . . . . . . . . . . . . . . . . . . . 7
5. Action Replace . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Action "replace" . . . . . . . . . . . . . . . . . . . . . . . 7
6. Action Enclose . . . . . . . . . . . . . . . . . . . . . . . . 8 6. Action "enclose" . . . . . . . . . . . . . . . . . . . . . . . 8
7. Action extract_text . . . . . . . . . . . . . . . . . . . . . 9 7. Action "extracttext" . . . . . . . . . . . . . . . . . . . . . 9
8. Sieve Capability Strings . . . . . . . . . . . . . . . . . . . 9 8. Sieve Capability Strings . . . . . . . . . . . . . . . . . . . 9
9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 10 9.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 10
9.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 10 9.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 10
9.3. Example 3 . . . . . . . . . . . . . . . . . . . . . . . . 11 9.3. Example 3 . . . . . . . . . . . . . . . . . . . . . . . . 11
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
11. Security Considerations . . . . . . . . . . . . . . . . . . . 12 11. Security Considerations . . . . . . . . . . . . . . . . . . . 12
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
12.1. for_every_part capability . . . . . . . . . . . . . . . . 13 12.1. foreverypart capability . . . . . . . . . . . . . . . . . 13
12.2. mime capability . . . . . . . . . . . . . . . . . . . . . 13 12.2. mime capability . . . . . . . . . . . . . . . . . . . . . 13
12.3. replace capability . . . . . . . . . . . . . . . . . . . . 14 12.3. replace capability . . . . . . . . . . . . . . . . . . . 14
12.4. enclose capability . . . . . . . . . . . . . . . . . . . . 14 12.4. enclose capability . . . . . . . . . . . . . . . . . . . 14
12.5. extract_text capability . . . . . . . . . . . . . . . . . 14 12.5. extracttext capability . . . . . . . . . . . . . . . . . 14
13. Change History (to be removed prior to publication as an 13. Change History . . . . . . . . . . . . . . . . . . . . . . . . 14
RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 13.1. draft-ietf-sieve-mime-05 . . . . . . . . . . . . . . . . 14
13.1. draft-ietf-sieve-mime-02 . . . . . . . . . . . . . . . . . 15 13.2. draft-ietf-sieve-mime-04 . . . . . . . . . . . . . . . . 15
13.2. draft-ietf-sieve-mime-01 . . . . . . . . . . . . . . . . . 15 13.3. draft-ietf-sieve-mime-03 . . . . . . . . . . . . . . . . 15
13.3. draft-ietf-sieve-mime-00 . . . . . . . . . . . . . . . . . 15 13.4. draft-ietf-sieve-mime-02 . . . . . . . . . . . . . . . . 15
13.4. draft-hansen-sieve-loop-01 . . . . . . . . . . . . . . . . 16 13.5. draft-ietf-sieve-mime-01 . . . . . . . . . . . . . . . . 15
13.5. draft-hansen-sieve-loop-02 . . . . . . . . . . . . . . . . 16 13.6. draft-ietf-sieve-mime-00 . . . . . . . . . . . . . . . . 16
13.6. draft-hansen-sieve-loop-03 . . . . . . . . . . . . . . . . 16 13.7. draft-sieve-mime-loop-04 . . . . . . . . . . . . . . . . 16
13.7. draft-sieve-mime-loop-04 . . . . . . . . . . . . . . . . . 16 13.8. draft-hansen-sieve-loop-03 . . . . . . . . . . . . . . . 16
13.9. draft-hansen-sieve-loop-02 . . . . . . . . . . . . . . . 17
13.10. draft-hansen-sieve-loop-01 . . . . . . . . . . . . . . . 17
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
14.1. Normative References . . . . . . . . . . . . . . . . . . . 17 14.1. Normative References . . . . . . . . . . . . . . . . . . 17
14.2. Informative References . . . . . . . . . . . . . . . . . . 17 14.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
Intellectual Property and Copyright Statements . . . . . . . . . . 19 Intellectual Property and Copyright Statements . . . . . . . . . . 19
1. Introduction 1. Introduction
MIME messages ([RFC2045]) are often complex objects, consisting of MIME messages ([RFC2045]) are often complex objects, consisting of
many parts and sub-parts. This extension defines mechanisms for many parts and sub-parts. This extension defines mechanisms for
performing tests on MIME body parts, looping through the MIME body performing tests on MIME body parts, looping through the MIME body
parts, extracting information from a MIME body part, changing the parts, extracting information from a MIME body part, changing the
contents of a MIME body part, and enclosing the entire message within contents of a MIME body part, and enclosing the entire message within
a wrapper. a wrapper.
2. Conventions Used in This Document 2. Conventions Used in This Document
Conventions for notations are as in [RFC5228] section 1.1. Conventions for notations are as in [RFC5228] section 1.1.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Sieve Loops 3. Sieve Loops: Actions "foreverypart" and "break"
The base Sieve language has no looping mechanism. Given that The base Sieve language has no looping mechanism. Given that
messages may contain multiple parts, in order to support filters that messages may contain multiple parts, in order to support filters that
apply to any and all parts, we introduce a new control command: apply to any and all parts, we introduce a new control command:
"for_every_part", which is an iterator that walks though every MIME "foreverypart", which is an iterator that walks though every MIME
part of a message, including nested parts, depth first, and applies part of a message, including nested parts, depth first, and applies
the commands in the specified block to each of them. The iterator the commands in the specified block to each of them. The iterator
will start with the first MIME part (as its current context) and will will start with the first MIME part (as its current context) and will
execute a command block (Sieve commands enclosed by {...}). Upon execute a command block (Sieve commands enclosed by {...}). Upon
completion of this command block, the iterator advances to the next completion of this command block, the iterator advances to the next
MIME part (as its current context) and executes the same command MIME part (as its current context) and executes the same command
block again. block again.
The iterator can be terminated prematurely by a new Sieve command, The iterator can be terminated prematurely by a new Sieve command,
"break". "break".
Usage: for_every_part block Usage: foreverypart [":name" string] block
Usage: break; Usage: break [":name" string];
"for_every_part" commands can be nested inside other "for_every_part" "foreverypart" commands can be nested inside other "foreverypart"
commands. When this occurs, the nested "for_every_part" iterates commands. When this occurs, the nested "foreverypart" iterates over
over the MIME parts contained within the MIME part currently being the MIME parts contained within the MIME part currently being
targeted by the nearest enclosing "for_every_part" command. If that targeted by the nearest enclosing "foreverypart" command. (That is,
MIME part is a terminal MIME part (i.e. does not contain other MIME the inner loop only operates on children of the bodypart currently
parts) then the nested "for_every_loop" is simply ignored. accessed by the outer loop.) If that MIME part is a terminal MIME
part (i.e. does not contain other MIME parts) then the nested
"foreverypart" loop is simply ignored.
Sieve implementations MAY limit the number of nested loops that occur Sieve implementations MAY limit the number of nested loops that occur
within one another, however they MUST support at least one nested within one another, however they MUST support at least one nested
loop inside another loop. loop inside another loop.
4. Changes to Sieve tests If a name is given to a "break" command, it terminates the closest
enclosing loop with the identical matching name. It is an error if
there is no enclosing loop with that name.
4. Changes to Sieve Tests
This specification extends the base Sieve "header", "address" and This specification extends the base Sieve "header", "address" and
"exists" tests to support targeting those tests at a specific MIME "exists" tests to support targeting those tests at a specific MIME
part or at all MIME parts in the enclosing scope. part or at all MIME parts in the enclosing scope.
4.1. Test "header" 4.1. Test "header"
The "header" test is extended with the addition of a new ":mime" The "header" test is extended with the addition of a new ":mime"
tagged argument and its associated options. tagged argument and its associated options.
Usage: header [:mime] [:anychild] [MIMEOPTS] Usage: header [":mime"] [":anychild"] [MIMEOPTS]
[COMPARATOR] [MATCH-TYPE] [COMPARATOR] [MATCH-TYPE]
<header-names: string-list> <key-list: string-list> <header-names: string-list> <key-list: string-list>
Usage: The definition of [MIMEOPTS] is: Usage: The definition of [MIMEOPTS] is:
Syntax: ":type" / ":subtype" / ":contenttype" / Syntax: ":type" / ":subtype" / ":contenttype" /
":param" <param-list: string-list> ":param" <param-list: string-list>
When the ":mime" tagged argument is present in the "header" test, it When the ":mime" tagged argument is present in the "header" test, it
will parse the MIME header lines in the message so that tests can be will parse the MIME header lines in the message so that tests can be
performed on specific elements. performed on specific elements.
When used outside the context of a "for_every_part" iterator, and When used outside the context of a "foreverypart" iterator, and
without an ":anychild" tagged argument, the "header" test will without an ":anychild" tagged argument, the "header" test will
examine only the outer top-level RFC2822 headers of the message. examine only the outer top-level RFC2822 headers of the message.
When used inside the context of a "for_every_part" iterator, and When used inside the context of a "foreverypart" iterator, and
without an ":anychild" tagged argument, the "header" test will without an ":anychild" tagged argument, the "header" test will
examine the headers associated with the current MIME part context examine the headers associated with the current MIME part context
from the loop. from the loop.
When used outside the context of a "for_every_part" iterator, and When used outside the context of a "foreverypart" iterator, and with
with an ":anychild" tagged argument, the "header" test will examine an ":anychild" tagged argument, the "header" test will examine all
all MIME body parts and return true if any of them satisfies the MIME body parts and return true if any of them satisfies the test.
test.
When used inside the context of a "for_every_part" iterator, and with When used inside the context of a "foreverypart" iterator, and with
an ":anychild" tagged argument, the "header" test will examine the an ":anychild" tagged argument, the "header" test will examine the
current MIME part context and all it's nested MIME body parts, current MIME part context and all it's nested MIME body parts,
returning true if any of them satisfies the test. returning true if any of them satisfies the test.
The "header" test with the ":mime" tagged argument can test various The "header" test with the ":mime" tagged argument can test various
aspects of certain structured MIME headers. These options are aspects of certain structured MIME headers. These options are
available: available:
:type parses the header assuming it has the format of a "Content- :type parses the header assuming it has the format of a "Content-
Type:" MIME header field, and tests the value of the MIME type Type:" MIME header field, and tests the value of the MIME type
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"Content-Type" "text/html" "Content-Type" "text/html"
{ {
fileinto "INBOX.html"; fileinto "INBOX.html";
} }
In this example, any message that contains any MIME part with a In this example, any message that contains any MIME part with a
content-type of "text/html" is saved to the mailbox "INBOX.html". content-type of "text/html" is saved to the mailbox "INBOX.html".
Example: Example:
require ["mime", "for_every_part", "fileinto"]; require ["mime", "foreverypart", "fileinto"];
for_every_part foreverypart
{ {
if allof ( if allof (
header :mime :param "filename" :contains header :mime :param "filename" :contains
"Content-Disposition" "important", "Content-Disposition" "important",
header :mime :subtype "Content-Type" "pdf", header :mime :subtype "Content-Type" "pdf",
size :over "100K") size :over "100K")
{ {
fileinto "INBOX.important"; fileinto "INBOX.important";
break; break;
} }
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In this example, any message that contains a MIME part that has a In this example, any message that contains a MIME part that has a
content-disposition with a filename parameter containing the text content-disposition with a filename parameter containing the text
"important", has a content-subtype of "pdf" and is bigger than 100 Kb "important", has a content-subtype of "pdf" and is bigger than 100 Kb
is saved to the mailbox "INBOX.important". is saved to the mailbox "INBOX.important".
4.2. Test "address" 4.2. Test "address"
The "address" test is extended with the addition of a new ":mime" The "address" test is extended with the addition of a new ":mime"
tagged argument, which takes a number of other arguments. tagged argument, which takes a number of other arguments.
Usage: address [:mime] [:anychild] [COMPARATOR] Usage: address [":mime"] [":anychild"] [COMPARATOR]
[ADDRESS-PART] [MATCH-TYPE] [ADDRESS-PART] [MATCH-TYPE]
<header-list: string-list> <key-list: string-list> <header-list: string-list> <key-list: string-list>
When the ":mime" tagged argument is present in the "address" test, it When the ":mime" tagged argument is present in the "address" test, it
will parse the MIME header lines as if they were standard address will parse the MIME header lines as if they were standard address
header lines in a message so that tests can be performed on specific header lines in a message so that tests can be performed on specific
elements. elements.
The behavior of the ":anychild" tagged argument and the interaction The behavior of the ":anychild" tagged argument and the interaction
with the "for_every_part" iterator is the same as for the extended with the "foreverypart" iterator is the same as for the extended
"header" test Section 4.1. "header" test Section 4.1.
Example: Example:
require ["mime", "fileinto"]; require ["mime", "fileinto"];
if address :mime :is :all "content-from" "tim@example.com" if address :mime :is :all "content-from" "tim@example.com"
{ {
fileinto "INBOX.part-from-tim"; fileinto "INBOX.part-from-tim";
} }
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"header" test Section 4.1. "header" test Section 4.1.
Example: Example:
require ["mime", "fileinto"]; require ["mime", "fileinto"];
if address :mime :is :all "content-from" "tim@example.com" if address :mime :is :all "content-from" "tim@example.com"
{ {
fileinto "INBOX.part-from-tim"; fileinto "INBOX.part-from-tim";
} }
In this example, any message that contains a MIME Content-From header In this example, any message that contains a MIME Content-From header
at the top-level matching the text "tim@example.com" is saved to the at the top-level matching the text "tim@example.com" is saved to the
mailbox "INBOX.part-from-time". mailbox "INBOX.part-from-time".
4.3. Test "exists" 4.3. Test "exists"
The "exists" test is extended with the addition of a new ":mime" The "exists" test is extended with the addition of a new ":mime"
tagged argument, which takes one other argument. tagged argument, which takes one other argument.
Usage: exists [:mime] [:anychild] <header-names: string-list> Usage: exists [":mime"] [":anychild"] <header-names: string-list>
When the ":mime" tagged argument is present in the "exists" test, the When the ":mime" tagged argument is present in the "exists" test, the
test is extended to check for the existence of MIME headers in MIME test is extended to check for the existence of MIME headers in MIME
parts. parts.
The behavior of the ":anychild" tagged argument and the interaction The behavior of the ":anychild" tagged argument and the interaction
with the "for_every_part" iterator is the same as for the extended with the "foreverypart" iterator is the same as for the extended
"header" test Section 4.1. "header" test Section 4.1.
Example: Example:
require ["mime", "fileinto"]; require ["mime", "fileinto"];
if exists :mime :anychild "content-md5" if exists :mime :anychild "content-md5"
{ {
fileinto "INBOX.md5"; fileinto "INBOX.md5";
} }
In this example, any message that contains a MIME Content-MD5 header In this example, any message that contains a MIME Content-MD5 header
in any MIME part is saved to the mailbox "INBOX.md5". in any MIME part is saved to the mailbox "INBOX.md5".
5. Action Replace 5. Action "replace"
Usage: replace [:mime] [:subject string] [:from string] Usage: replace [":mime"] [":subject" string] [":from" string]
<replacement: string> <replacement: string>
The "replace" command is defined to allow a MIME part to be replaced The "replace" command is defined to allow a MIME part to be replaced
with the text supplied in the command. with the text supplied in the command.
When used in the context of a "for_every_part" iterator, the MIME When used in the context of a "foreverypart" iterator, the MIME part
part to be replaced is the "current" MIME part. If the current MIME to be replaced is the "current" MIME part. If the current MIME
context is a multipart MIME part, the entire multipart MIME part is context is a multipart MIME part, the entire multipart MIME part is
replaced, which would alter the MIME structure of the message by replaced, which would alter the MIME structure of the message by
eliminating all of the children of the multipart part. (Replacing a eliminating all of the children of the multipart part. (Replacing a
non-multipart MIME part within a "for_every_part" loop context does non-multipart MIME part within a "foreverypart" loop context does not
not alter the overall message structure.) If the MIME structure is alter the overall message structure.) If the MIME structure is
altered, the change takes effect immediately: the "for_every_part" altered, the change takes effect immediately: the "foreverypart"
iterator that is executing does not go into the no-longer existing iterator that is executing does not go into the no-longer existing
body parts, and subsequent "for_every_part" iterators would use the body parts, and subsequent "foreverypart" iterators would use the new
new message structure. message structure.
When used outside the context of a "for_every_part" loop, the MIME When used outside the context of a "foreverypart" loop, the MIME part
part to be replaced is the entire message. to be replaced is the entire message.
If the :mime parameter is not specified, the replacement string is a If the :mime parameter is not specified, the replacement string is a
text/plain part in UTF-8. text/plain part in UTF-8.
If the :mime parameter is specified, then the replacement string is, If the :mime parameter is specified, then the replacement string is,
in fact, a MIME entity as defined in [RFC2045] section 2.4, including in fact, a MIME entity as defined in [RFC2045] section 2.4, including
both MIME headers and content. both MIME headers and content.
If the entire message is being replaced, a ":subject" parameter If the entire message is being replaced, a ":subject" parameter
specifies a subject line to attach to the message that is generated. specifies a subject line to attach to the message that is generated.
skipping to change at page 8, line 35 skipping to change at page 8, line 36
used to specify an alternate address to use in the From field of the used to specify an alternate address to use in the From field of the
message that is generated. The string must specify a valid [RFC2822] message that is generated. The string must specify a valid [RFC2822]
mailbox-list. Implementations SHOULD check the syntax and generate mailbox-list. Implementations SHOULD check the syntax and generate
an error when a syntactically invalid ":from" parameter is specified. an error when a syntactically invalid ":from" parameter is specified.
Implementations MAY also impose restrictions on what addresses can be Implementations MAY also impose restrictions on what addresses can be
specified in a ":from" parameter; it is suggested that values that specified in a ":from" parameter; it is suggested that values that
fail such a validity check simply be ignored rather than causing the fail such a validity check simply be ignored rather than causing the
replace action to fail. Implementations MUST preserve the previous replace action to fail. Implementations MUST preserve the previous
From header as an Original-From header. From header as an Original-From header.
6. Action Enclose 6. Action "enclose"
Usage: enclose <:subject string> <:headers string-list> string Usage: enclose <:subject string> <:headers string-list> string
A new Sieve action command is defined to allow an entire message to A new Sieve action command is defined to allow an entire message to
be enclosed as an attachment to a new message. After enclosure, be enclosed as an attachment to a new message. After enclosure,
subsequent actions affecting the message header or content use the subsequent actions affecting the message header or content use the
newly created message instead of the original message; this means newly created message instead of the original message; this means
that any use of a "replace" action or other similar actions should be that any use of a "replace" action or other similar actions should be
executed before the "enclose" action. executed before the "enclose" action.
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Specifically, the original message becomes a multipart/mixed message Specifically, the original message becomes a multipart/mixed message
with two parts: a text/plain portion with the string argument as its with two parts: a text/plain portion with the string argument as its
body, and a message/rfc822 portion with the original message body, and a message/rfc822 portion with the original message
enclosed. The Content-Type: header field becomes multipart/mixed. enclosed. The Content-Type: header field becomes multipart/mixed.
The Subject: header is specified by the :subject argument. Any The Subject: header is specified by the :subject argument. Any
headers specified by :headers are copied from the old message into headers specified by :headers are copied from the old message into
the new message. If not specified by :headers, Date: and From: the new message. If not specified by :headers, Date: and From:
headers should be synthesized to reflect the current date and the headers should be synthesized to reflect the current date and the
user running the Sieve action. user running the Sieve action.
7. Action extract_text 7. Action "extracttext"
Usage: extract_text [MODIFIER] [":first" number] <varname: string> Usage: extracttext [MODIFIER] [":first" number] <varname: string>
The extract_text action may be used within the context of a The extracttext action may be used within the context of a
"for_every_part" loop. Servers MUST support transcoding of any "foreverypart" loop. Servers MUST support transcoding of any textual
textual body part into UTF-8 for use with this action. This requires body part into UTF-8 for use with this action. This requires
decoding any transfer encoding as well as transcoding from the decoding any transfer encoding as well as transcoding from the
indicated character set into UTF-8. It stores at most :first indicated character set into UTF-8. It stores at most :first
characters of the transcoded content of the current MIME body part in characters of the transcoded content of the current MIME body part in
the variable identified by varname. If the :first parameter is not the variable identified by varname. If the :first parameter is not
present, the whole content of the current MIME body part is stored. present, the whole content of the current MIME body part is stored.
In either case the actually stored data MAY be truncated to conform In either case the actually stored data MAY be truncated to conform
to implementation-specific limit on variable length and/or on MIME to implementation specific limit on variable length and/or on MIME
body part length. If the transfer encoding or character set is body part length. If the transfer encoding or character set is
unrecognized by the implementation or recognized but invalid, an unrecognized by the implementation or recognized but invalid, an
empty string will result. empty string will result.
If extract_text is used outside the context of a "for_every_part" If extracttext is used outside the context of a "foreverypart" loop,
loop, the action will set the variable identified by varname to the the action will set the variable identified by varname to the empty
empty string. string.
Modifiers are applied on the extracted text before it is stored in Modifiers are applied on the extracted text before it is stored in
the variable. See [RFC5229] for details. the variable. See [RFC5229] for details.
8. Sieve Capability Strings 8. Sieve Capability Strings
A Sieve implementation that defines the "for_every_part" and "break" A Sieve implementation that defines the "foreverypart" and "break"
actions will advertise the capability string "for_every_part". actions will advertise the capability string "foreverypart".
A Sieve implementation that defines the ":mime" and ":anychild" A Sieve implementation that defines the ":mime" and ":anychild"
tagged arguments to the "header", "address" and "exists" tests will tagged arguments to the "header", "address" and "exists" commands
advertise the capability string "mime". will advertise the capability string "mime".
A Sieve implementation that defines the "replace" action will A Sieve implementation that defines the "replace" action will
advertise the capability string "replace". advertise the capability string "replace".
A Sieve implementation that defines the "enclose" action will A Sieve implementation that defines the "enclose" action will
advertise the capability string "enclose". advertise the capability string "enclose".
A Sieve implementation that defines the "extract_text" action will A Sieve implementation that defines the "extracttext" action will
advertise the capability string "extract_text". Note that to be advertise the capability string "extracttext". Note that to be
useful, the "extract_text" action also requires the "variables" useful, the "extracttext" action also requires the "variables"
[RFC5229] and "for_every_part" capabilities. [RFC5229] and "foreverypart" capabilities.
9. Examples 9. Examples
9.1. Example 1 9.1. Example 1
A Sieve script to replace all the Windows executable attachments in a A Sieve script to replace all the Windows executable attachments in a
message would be: message would be:
require [ "for_every_part", "mime", "replace" ]; require [ "foreverypart", "mime", "replace" ];
for_every_part foreverypart
{ {
if anyof ( if anyof (
header :mime :contenttype :is "Content-Type" "application/exe", header :mime :contenttype :is "Content-Type" "application/exe",
header :mime :param "filename" header :mime :param "filename"
["Content-Type", "Content-Disposition"] :matches "*.com" ) ["Content-Type", "Content-Disposition"] :matches "*.com" )
{ {
replace "Executable attachment removed by user filter"; replace "Executable attachment removed by user filter";
} }
} }
9.2. Example 2 9.2. Example 2
A Sieve script to warn the user about executable attachment types A Sieve script to warn the user about executable attachment types
would be: would be:
require [ "for_every_part", "mime", "enclose" ]; require [ "foreverypart", "mime", "enclose" ];
for_every_part foreverypart
{ {
if header :mime :param "filename" if header :mime :param "filename"
["Content-Type", "Content-Disposition"] :matches ["Content-Type", "Content-Disposition"] :matches
["*.com", "*.exe", "*.vbs", "*.scr", ["*.com", "*.exe", "*.vbs", "*.scr",
"*.pif", "*.hta", "*.bat", "*.zip" ] "*.pif", "*.hta", "*.bat", "*.zip" ]
{ {
# these attachment types are executable # these attachment types are executable
enclose :subject "Warning" :text enclose :subject "Warning" :text
WARNING! The enclosed message contains executable attachments. WARNING! The enclosed message contains executable attachments.
These attachments types may contain a computer virus program These attachments types may contain a computer virus program
skipping to change at page 12, line 5 skipping to change at page 12, line 5
. .
break; break;
} }
} }
9.3. Example 3 9.3. Example 3
A Sieve script to extract subject and text out of messages from the A Sieve script to extract subject and text out of messages from the
boss: boss:
require ["mime", "variables", "extract_text"]; require ["mime", "variables", "extracttext"];
if header :contains "from" "boss@example.org" if header :contains "from" "boss@example.org"
{ {
# :matches is used to get the value of the Subject header # :matches is used to get the value of the Subject header
if header :matches "Subject" "*" if header :matches "Subject" "*"
{ {
set "subject" "${1}"; set "subject" "${1}";
} }
# extract the first 100 characters of the first text/* part # extract the first 100 characters of the first text/* part
for_every_part foreverypart
{ {
if header :mime :type :is "Content-Type" "text" if header :mime :type :is "Content-Type" "text"
{ {
extract_text :first 100 "msgcontent"; extracttext :first 100 "msgcontent";
break; break;
} }
} }
# if it's not a 'for your information' message # if it's not a 'for your information' message
if not header :contains "subject" "FYI:" if not header :contains "subject" "FYI:"
{ {
# do something using ${subject} and ${msgcontent} # do something using ${subject} and ${msgcontent}
# such as sending a notification using a # such as sending a notification using a
# notification extensions # notification extension
} }
} }
10. Acknowledgements 10. Acknowledgements
Comments from members of the MTA Filters Working Group, in particular Comments from members of the MTA Filters Working Group, in particular
Ned Freed, Kjetil Torgrim Homme, Mark Mallett, Alexey Melnikov, Aaron Ned Freed, Kjetil Torgrim Homme, Mark Mallett, Alexey Melnikov, Aaron
Stone and Nigel Swinson are gratefully acknowledged. Stone and Nigel Swinson are gratefully acknowledged.
11. Security Considerations 11. Security Considerations
skipping to change at page 13, line 25 skipping to change at page 13, line 25
12. IANA Considerations 12. IANA Considerations
The Original-Subject: and Original-From: headers are to be registered The Original-Subject: and Original-From: headers are to be registered
in the Permanent Message Header Fields table. in the Permanent Message Header Fields table.
The following templates specify the IANA registrations of the Sieve The following templates specify the IANA registrations of the Sieve
extensions specified in this document. This information should be extensions specified in this document. This information should be
added to the list of sieve extensions given on added to the list of sieve extensions given on
http://www.iana.org/assignments/sieve-extensions. http://www.iana.org/assignments/sieve-extensions.
12.1. for_every_part capability [[ RFC Editor Note: replace RFC XXXX with a reference to this RFC. ]]
To: iana@iana.org 12.1. foreverypart capability
To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: for_every_part Capability name: foreverypart
Description: adds the "foreverypart" and "break" actions for
Description: adds the "for_every_part" and "break" actions for
iterating through MIME parts of a message. iterating through MIME parts of a message.
RFC number: This RFC RFC number: RFC XXXX
Contact address: The Sieve discussion list Contact address: The Sieve discussion list
<ietf-mta-filters@imc.org>. <ietf-mta-filters@imc.org>.
12.2. mime capability 12.2. mime capability
To: iana@iana.org To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: mime Capability name: mime
Description: adds the ":mime" and ":anychild" tagged arguments to the Description: adds the ":mime" and ":anychild" tagged arguments to the
"header", "address" and "exists" tests. "header", "address" and "exists" tests.
RFC number: This RFC RFC number: RFC XXXX
Contact address: The Sieve discussion list Contact address: The Sieve discussion list
<ietf-mta-filters@imc.org>. <ietf-mta-filters@imc.org>.
12.3. replace capability 12.3. replace capability
To: iana@iana.org To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: mime Capability name: replace
Description: adds the "replace" action for replacing a MIME body part Description: adds the "replace" action for replacing a MIME body part
of a message. of a message.
RFC number: This RFC RFC number: RFC XXXX
Contact address: The Sieve discussion list Contact address: The Sieve discussion list
<ietf-mta-filters@imc.org>. <ietf-mta-filters@imc.org>.
12.4. enclose capability 12.4. enclose capability
To: iana@iana.org To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: enclose
Capability name: mime
Description: adds the "enclose" action for enclosing a message with a Description: adds the "enclose" action for enclosing a message with a
wrapper. wrapper.
RFC number: This RFC RFC number: RFC XXXX
Contact address: The Sieve discussion list Contact address: The Sieve discussion list
<ietf-mta-filters@imc.org>. <ietf-mta-filters@imc.org>.
12.5. extract_text capability 12.5. extracttext capability
To: iana@iana.org To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: extracttext
Description: adds the "extracttext" action for extracting text from a
MIME body part.
Capability name: mime RFC number: RFC XXXX
Contact address: The Sieve discussion list
<ietf-mta-filters@imc.org>.
Description: adds the "extract_text" action for extracting text from 13. Change History
a MIME body part.
RFC number: This RFC [[ RFC Editor NOTE: This section is to be removed prior to
publication as an RFC. ]]
Contact address: The Sieve discussion list 13.1. draft-ietf-sieve-mime-05
<ietf-mta-filters@imc.org>.
13. Change History (to be removed prior to publication as an RFC) Changed for_every_part to foreverypart, and extract_text to
extracttext.
13.1. draft-ietf-sieve-mime-02 Add option :name parameter to foreverypart and break. break :name
"string" will break out of closest enclosing foreverypart loop
with that name.
Clarify nesting a bit more.
Minor consistency nit picking.
13.2. draft-ietf-sieve-mime-04
loops are depth first
:anychild clarifications
update examples
grammar nits
transcoding for extract_text
13.3. draft-ietf-sieve-mime-03
add extraction
add security considerations
fill in iana considerations
13.4. draft-ietf-sieve-mime-02
minor syntax glitches in examples minor syntax glitches in examples
Add clarification on "replace" affecting subsequent for_every_part Add clarification on "replace" affecting subsequent for_every_part
loops? loops?
Add IANA considerations for Original-Subject: and Original-From:. Add IANA considerations for Original-Subject: and Original-From:.
Add note on "enclose" creating From: and Date: headers. Add note on "enclose" creating From: and Date: headers.
13.2. draft-ietf-sieve-mime-01 13.5. draft-ietf-sieve-mime-01
what happens when nested for_every_loop's what happens when nested for_every_part loop's
a "mime" shorthand for testing the type/subtype, without requiring a "mime" shorthand for testing the type/subtype, without requiring
interactions with variables interactions with variables
notifications notifications
notifications to calendar service notifications to calendar service
address tests, exists tests address tests, exists tests
mimeheader, mimeparameter tests mimeheader, mimeparameter tests
13.3. draft-ietf-sieve-mime-00 13.6. draft-ietf-sieve-mime-00
Changed title and text to emphasize MIME Tests. Changed title and text to emphasize MIME Tests.
Changed for.every.part to for_every_part. Changed for.every.part to for_every_part.
Added :anychild to mime test. Default is to use the current context Added :anychild to mime test. Default is to use the current
or outer envelope; specifying :anychild will look at all children. context or outer envelope; specifying :anychild will look at all
children.
Added clarifications to replacing parts affecting the structure. Added clarifications to replacing parts affecting the structure.
Added :mime option to replace, ala draft-ietf-sieve-vacation-06. Added :mime option to replace, ala draft-ietf-sieve-vacation-06.
Various other minor nit fixes. Various other minor nit fixes.
13.4. draft-hansen-sieve-loop-01 13.7. draft-sieve-mime-loop-04
Merged with draft-daboo-sieve-mime-00.txt.
13.5. draft-hansen-sieve-loop-02
Update to 3028bis reference.
Added 2119 conventions section.
Terminology/title tweaks. update reference for recent published rfcs
Added informative references to body and editheader extensions. extract-text now required to do decode transfer encoding and
transcode to UTF-8
Added description of nested loops. removed editheader reference since its not actually used
Replaced mime test by extensions to header, address and exists several text changes as suggested by Nigel Swinson, including re-
tests. writes to abstract and introduction
13.6. draft-hansen-sieve-loop-03 13.8. draft-hansen-sieve-loop-03
after enclosure, subsequent actions affect newly created message after enclosure, subsequent actions affect newly created message
synthesis of Date/From headers by the enclose action is no longer synthesis of Date/From headers by the enclose action is no longer
controversial controversial
Filled in Security Considerations Filled in Security Considerations
Picked up extract_text action from draft-ietf-sieve-notify Picked up extract_text action from draft-ietf-sieve-notify
Expanded the IANA considerations section Expanded the IANA considerations section
13.7. draft-sieve-mime-loop-04 13.9. draft-hansen-sieve-loop-02
update reference for recent published rfcs Update to 3028bis reference.
extract-text now required to do decode transfer encoding and Added 2119 conventions section.
transcode to UTF-8
removed editheader reference since its not actually used Terminology/title tweaks.
several text changes as suggested by Nigel Swinson, including re- Added informative references to body and editheader extensions.
writes to abstract and introduction
tweaked IANA registrations Added description of nested loops.
Replaced mime test by extensions to header, address and exists
tests.
13.10. draft-hansen-sieve-loop-01
Merged with draft-daboo-sieve-mime-00.txt.
14. References 14. References
14.1. Normative References 14.1. Normative References
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996. Bodies", RFC 2045, November 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions) [RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
skipping to change at page 17, line 28 skipping to change at page 17, line 49
[RFC2822] Resnick, P., "Internet Message Format", RFC 2822, [RFC2822] Resnick, P., "Internet Message Format", RFC 2822,
April 2001. April 2001.
[RFC5228] Guenther, P. and T. Showalter, "Sieve: An Email Filtering [RFC5228] Guenther, P. and T. Showalter, "Sieve: An Email Filtering
Language", RFC 5228, January 2008. Language", RFC 5228, January 2008.
14.2. Informative References 14.2. Informative References
[I-D.ietf-sieve-body] [I-D.ietf-sieve-body]
Guenther, P. and J. Degener, "Sieve Email Filtering: Body Guenther, P. and J. Degener, "Sieve Email Filtering: Body
Extension", draft-ietf-sieve-body-07 (work in progress), Extension", draft-ietf-sieve-body-09 (work in progress),
December 2007. March 2008.
[RFC5229] Homme, K., "Sieve Email Filtering: Variables Extension", [RFC5229] Homme, K., "Sieve Email Filtering: Variables Extension",
RFC 5229, January 2008. RFC 5229, January 2008.
Authors' Addresses Authors' Addresses
Tony Hansen Tony Hansen
AT&T Laboratories AT&T Laboratories
200 Laurel Ave. 200 Laurel Ave.
Middletown, NJ 07748 Middletown, NJ 07748
skipping to change at page 19, line 44 skipping to change at line 825
attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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