Simpler and more conformant keepalive feature #406
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Before the change, the keepalive was always sent, even if the thread had completed before the join timeout. After the change, we break the loop immediately after the thread join if the folder load is complete.
When the load folder thread join timeout expires send a keepalive message of the form: * OK in progress... This response is conform to RFC3501 and understood by Python's imaplib, used by offlineimap3. See sections 7.1 and 7.1.1 of RFC3501 (IMAP4rev1), sections 7.1 and 7.1.1 of RFC9051 (IMAP4rev2), and RFC9585 (response code INPROGRESS). Fixes: mguessan#41 mguessan#122 mguessan#343. Linked-to: python/cpython#81588 python/cpython#117152 python/cpython#62353.
Perform the long-running in the main thread, and start a parallel thread to send the keep-alive message at regular interval. This makes the code more regular and the feature more encapsulated. The parallel thread is started only when the number of messages to load is greater than 500, and the keep-alive feature is enables. The keep-alive thread is canceled as soon as the folder has loaded its messages. The keep-alive task is scheduled to be sent every 20 s, after an initial delay of 20 s.
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Time and again, @mguessan's response has to been that, if you don't want two spaces, then to set and that doing so should "please Python's imaplib", as you put it. Did you try doing that? Is that not the case? Does your PR also fix the issue with client's timing out when interacting with large folders in a way that's superior to the current workaround employed for large folders when |
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Yes I have tried the official workaround of disabling the keepalive feature, and indeed However, I was convinced that it was possible to implement a keepalive mechanism conforming to the IMAP protocol. I think that I have found such a solution. The second commit in the branch sends an untagged
RFC 9585 adds an untagged response code However Davmail implements RFC 3501 (IMAP4rev1) which states (§ 7.1):
So it is a bit risky to send this unexpected/unknown response code to clients. On the other hand RFC 9051 (IMAP4rev2) states:
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I like this new approach to implement keepalive using only standard responses. Would need some testing to confirm we don't get any regressions. |
git-svn-id: https://svn.code.sf.net/p/davmail/code/trunk@3716 3d1905a2-6b24-0410-a738-b14d5a86fcbd
The
keepalivefeature of DavMail is implemented in a way that doesn't please Python'simaplib, and by extensionofflineimap3. There must be exactly one space after the*in an untagged response. See commit messages for more details.This branch is (I believe) a proper fix for issues #41 #122 #343. As a bonus, I've rewritten the logic to make the keepalive code path a pure addition on top of the regular code path (main thread).
I have had these patches over release 6.2.1 for some months now.
Thanks for this project.