| Internet-Draft | IANA registry for Sieve actions | December 2022 |
| Melnikov & Murchison | Expires 24 June 2023 | [Page] |
Sieve Email Filtering Language (RFC 5228) is a popular email filtering language used upon final mail delivery. This document creates a registry of Sieve (RFC 5228) actions in order to help developers and Sieve extension writers track interactions between different extensions.¶
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Sieve Email Filtering Language [RFC5228] is a popular email filtering language used upon final mail delivery. Popularity of Sieve resulted in a myriad of Sieve extensions that can interact with each other in wonderful and complex ways. There is currently no easy way to find out all actions defined by Sieve extensions published in RFCs, which make it quite difficult for Sieve extension writers and Sieve implementation developers to forsee interactions between Sieve actions.¶
This document creates a registry of Sieve [RFC5228] actions in order to help developers and Sieve extension writers track interactions between different extensions.¶
IANA is requested to create a new registry for Sieve actions (see Section 2.9 of [RFC5228] for details on Sieve actions). Registration of both actions specified in IETF Stream RFCs and vendor specific actions is allowed and encouraged. The registration template contains:¶
Registration procedure for this registry is Expert Review. The Designated Expert only checks that the name of the action being registered matches documentation, that the description field is accurate, that the correct documents are referenced and that the list of relevant documents is as complete as possible. The Designated Expert can't reject a registration based on personal dislike of the document defining an action and should always err on the side of registering, even if documentation is not complete.¶
Addition of a new reference to an existing registration or change to the description field goes through the same registration procedure as a new registration.¶
The following table is used to initialize the actions registry. Note that when "Action Interactions" cell is empty it means that there is no restriction on use of the corresponding action with any other action, however implementors still need to read the corresponding specification(s) to see if there is are any surprising behaviour. Also note that the "Comments" field of the registration template is omitted from this table, as no registration currently have any comment.¶
| Name | Description | References | Capabilities | Action Interactions | Cancels Implicit Keep? | Can use with IMAP Events? |
|---|---|---|---|---|---|---|
| addheader | Add a header field to the existing message header | [RFC5293] | "editheader" | All subsequent tests and actions apply to the altered message | No | Yes |
| addflag | Add IMAP flags to a list of IMAP flags that would be set on the message if it gets delivered to a mailbox | [RFC5232], [RFC5229] | "imap4flags", "variables" | No | Yes | |
| convert | Convert body parts from one MIME type to another | [RFC6558] | "convert" | All subsequent tests and actions apply to the altered message | No | Yes |
| deleteheader | Remove a header field from the existing message header | [RFC5293] | "editheader" | All subsequent tests and actions apply to the altered message | No | Yes |
| discard | Silently throw away the message | [RFC5228] | Yes | Yes | ||
| enclose | Enclose a message as an attachment to a new message | [RFC5703] | "enclose" | All subsequent tests and actions, except "redirect" apply to the altered message | No | Yes |
| ereject | Refuse delivery of the message | [RFC5429] | "ereject" | Incompatible with "vacation" action. Typically is not permitted with actions that cause mail delivery, such as "keep", "fileinto", and "redirect". | Yes | No |
| extracttext | Store text of a MIME part into a variable | [RFC5703], [RFC5229] | "extracttext", "variables" | No | Yes | |
| fileinto | Deliver the message into the specified mailbox | [RFC5228], [RFC3894], [RFC5232], [RFC5490], [RFC9042], [RFC8579] | "fileinto", "copy", "imap4flags", "mailbox", "mailboxid", "special-use" | Use of :copy suppresses cancelation of implicit keep | Yes | Yes |
| keep | File message into the user's main mailbox | [RFC5228], [RFC5232] | "imap4flags" | Yes | Yes | |
| notify | Send a notification to a user | [RFC5435], [RFC8580] | "enotify", "fcc" | No | Yes | |
| redirect | Send (forward) the message to another user | [RFC5228], [RFC3894], [RFC6009], [RFC6134] | "copy", "redirect-dsn", "redirect-deliverby", "extlists" | Use of :copy suppresses cancelation of implicit keep | Yes | Yes |
| reject | Refuse delivery of the message | [RFC5429] | "reject" | Incompatible with "vacation" action. Typically is not permitted with actions that cause mail delivery, such as "keep", "fileinto", and "redirect". | Yes | No |
| removeflag | Remove IMAP flags from a list of IMAP flags that would be set on the message if it gets delivered to a mailbox | [RFC5232], [RFC5229] | "imap4flags", "variables" | No | Yes | |
| replace | Replace a MIME part | [RFC5703] | "replace" | All subsequent tests and actions, except "redirect" apply to the altered message | No | Yes |
| set | Store a value in a variable | [RFC5229] | "variables" | No | Yes | |
| setflag | Set IMAP system flags or keywords that would be set on the message if it gets delivered to a mailbox | [RFC5232], [RFC5229] | "imap4flags", "variables" | No | Yes | |
| vacation | Vacation autoresponder | [RFC5230], [RFC6131], [RFC8580] | "vacation", "vacation-seconds", "fcc" | Incompatible with "reject" and "ereject" actions. | No | No |
The sole purpose of this document is to create a new IANA registry, so it doesn't create new security considerations for Sieve implementations.¶
The new registry should help Sieve extension writers and Sieve implementors track interactions between different Sieve actions, so it might improve quality of specifications and implementations, including security aspects.¶
For the Security Considerations of particular actions, see the RFC(s) referenced for that action in the Initial Sieve Action Registry in Section 2.2.¶
TBD.¶