PopTrayU Progress: Unread Message Filtering

There was a user requested feature for PopTrayU to add filtering based on read/unread status. This is something that is only technically feasible for IMAP since POP servers don’t store read/unread status. Anyway, I started working on implementing this feature, and decided that if you are only showing unread messages, you might need a mechanism to change the read/unread status–especially if previewing automatically marks the message read on the server.

So whip up some code for this…go to test it…and…nothing. No change to the message status.  Turn on some logging of server communication, and something looks off about the command set to the server…and the server response? Yeah, pretty sure that’s not what’s supposed to happen either.

Sent: C4 UID STORE 1264  (\Seen)<EOL>
Recv: C4 BAD Error in IMAP command UID STORE: Invalid STORE modifiers.<EOL>

This may not be so apparent in a non-monospaced font, but there’s a double space between 1264 and (\Seen) like a token got left out. But not being intimately aquainted with every nuance of the IMAP spec, I had to lookup the section on setting flags in the IMAP RFC for IMAP to be sure I even knew what the command was supposed to look like. It’s supposed to have a +FLAGS.SILENT in that missing token.

So, long story short, I had to update my copy of Indy from SVN to make sure the bug still existed on top of trunk, then I had to debug a variable type that disappeared in the new version of indy (it got replaced with something else), after retesting and trying a couple variants to see if it only exhibited this behavior when certain parameters were used, I filed a bug report to let the Indy team know about this issue, and left my code using a workaround with the better code commented out in the meantime. Remy and the Indy team are pretty responsive to fixing actual bugs, especially ones that are probably pretty trivial to fix like this (now incredibly useful but difficult to implement enhancements on the other hand, like IMAP IDLE I’m not about to hold my breath over…).

Aside from this particular sub-feature, there’s still quite a bit that needs to be done to make “unread only” mode happen. Like, the main window needs a whole new paradigm of basing the read/unread status off of the server for IMAP and off internal tracking for POP. And the message list needs to be using UIDs instead of relative message numbers for a bunch of different commands including but not limited to preview and delete.

And while I’m at changing it to download by UIDs, this would be a good time to evaluate whether it should be downloading only the “message envelope” (a limited set of headers that basically are the headers you see in your email client message list) instead of the “full headers” (including all the headers you usually don’t read like spam checker versions and hosts that redirected the email and so on that could be useful for rules) the way it does now. If you’re not making rules that use the extended headers, this could cut data transfer in about half, which could be a significant time saver on large inboxes, so it’s worth looking into, even though I’d probably still have to also support having the existing modes to support users who use those headers to create complex rules. And while I’m doing that…and so on and so forth it goes 😉

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