Filters

Filters and the vacation responder live in the mailbox's Sieve script on the mail server, which runs it as each message is delivered. Viauna holds no copy. For setting it up, see Filters and vacation; for using it, Filters and the vacation responder.

Reading and saving

Each time Viauna loads them (for the Filters tab, or the vacation responder in Settings > General) or saves a change, it opens a ManageSieve connection (RFC 5804): STARTTLS unless MANAGESIEVE_SECURITY says otherwise, never falling back to sending the password in the clear; then it signs in as the mailbox with its own login and password (SASL PLAIN), does the work and logs out. It gives up after 15 s without an answer.

A save:

1. reads the current script, and lists which other script is active;
2. writes the new script from Viauna's own model, require-ing only the Sieve extensions its rules use, and refuses, naming them, if the server lacks any;
3. has the server check it (CHECKSCRIPT), saves it (PUTSCRIPT) and makes it the active one (SETACTIVE).

A filter that skips the Inbox needs an Archive folder, so saving one makes Archive if the mailbox has none.

The script

Viauna owns one script per mailbox, called viauna. In order, it holds:

1. the vacation responder, first, so a reply is sent even for mail a filter moves;
2. each filter, in the order listed;
3. include :personal :optional for a script another app made (Roundcube's, say) that was active when Viauna saved, up to five, so those rules keep running.

There's no stop anywhere, so every filter that matches applies, and the other app's rules run after Viauna's. When no filters and no vacation responder are left, Viauna deletes its script and makes the first included script active again.

The script starts with two comments: # viauna-model:, Viauna's filters and vacation responder as base64 JSON, which is how it reads them back exactly; and # viauna-hash:, the SHA-256 of the rules below. If the rules no longer match the hash, someone edited the script elsewhere: Viauna says so, and saving replaces their edit.

What each filter becomes

In Viauna	In Sieve
From	header :contains "from", any of the values separated by commas or OR
To	header :contains ["to", "cc"], the same way
Subject	header :contains "subject" with the whole text: it matches that text as typed, not each word anywhere in the subject
Has the words	body :text :contains for each word, or each "quoted phrase": all must be in the message's text (not its headers)
Doesn't have	not body :text :contains, any of the words
Has attachment	A part with Content-Disposition: attachment (images shown inside the message don't count)
Size	size :over or size :under, in bytes
Mark as read, Star it, Apply the label	addflag with \Seen, \Flagged or the label's IMAP keyword
Forward it to	redirect :copy, so the mailbox keeps the message too
Skip the Inbox	fileinto the Archive folder
Move to	fileinto that folder
Delete it	fileinto Trash

Text is matched ignoring the case of ASCII letters, Sieve's default.

Some consequences:

• Two filters that file the same message (move, skip the Inbox or delete) put a copy in each folder.
• Flags carry forward. A label, read mark or star from one filter is set wherever a later filter files the message.
• Renaming or deleting a label changes the messages, but not the filters that apply it: they keep adding the old label's keyword, so it comes back on new mail. Edit those filters after renaming a label.
• A folder used by Move to that's renamed or deleted isn't made again: its mail stays in the Inbox until the filter is edited.
• Mail filed into other folders appears in Viauna within a minute, not a second; see Mail sync.

The vacation responder

It becomes vacation :days 4, with the subject, the message and :addresses listing the mailbox's address and its confirmed "Send mail as" addresses (see Sending as other addresses); the script is written again when one is confirmed or removed. The server remembers whom it replied to, so each sender gets at most one reply every four days, and it replies only to mail sent to one of those addresses. The first and last days are checked with currentdate, at the UTC offset of the browser that saved them: across a change to or from summer time, the day starts an hour off.

When forwarding is off

With FILTER_FORWARDING off, a filter that forwards can't be saved: saving the filters asks for the forwarding to be removed first. Saving only the vacation responder leaves the filters as they were, forwarding included.