I have an account on an SMTP server. The server has a storage quota. I'd like the delete stuff from the server but keep it locally in case I need it. Just in case.
I'd like to be able to access the mail somehow on other computers and hopefully mobile devices on my network so that it can be searched when needed. I'm not sure what the best interface for that would be. A webmail client?
One option would be to use Thunderbird or another client to download the mail once in a while but disable deleting local messages when they are removed from the server. Would Thunderbird store the messages in a format I can use readily with other applications? Or should I use something else to download the mail?
What about situations where messages are moved from one folder to another on the server? Would I get a duplicate locally of the message appearing in both locations? Not sure how the storage and metadata actually are.
Also, is it possible in such a situation to put a message back on the server if I realize it was deleted in error?
Any idea would be welcome. I am a bit stuck.
I can use the command line comfortably but ideally I'd have a solution that doesn't rely on the terminal to find find messages and such. I don't really like terminal mail clients.
What I do is use Claws Mail with POP3, it has an option that allows a message to only be deleted from the server after a configurable period of time. So if you set it for 10 days for example the message will exist both locally on your PC and on the server for 10 days, after which it will only exist on the PC.
It works pretty well in general. The only account giving me some trouble is Yahoo, which I suspect has some quirks, which occasionally cause the messages to be downloaded again and duplicated. Thankfully it's easily fixed because Claws also has a feature to delete duplicates.
This approach is different from IMAP, which would maintain a local offline cache of the live inbox, but you wouldn't be able to only keep local messages — any change in one side would be reflected in both.
However, Claws allows you to do both. You can have both a POP3 and an IMAP account connected to the same live box use the POP3 for offline archival, and the IMAP for when you want to put something back on the server, or if you need to look at other folders on the server besides inbox (POP3 cab only see the inbox, not trash, sent etc.)
Normally I only do folders locally on the PC, on the mailbox connected with POP3, so none of the organization is reflected on the live mailbox, which is inbox only. Every once in a while I connect via IMAP to recover emails from the sent folder, which I've sent with webmail or from mobile (using IMAP on mobile too).
If this doesn't fit your workflow turn there are lots of IMAP syncing tools like you've noticed. IMAPsync is pretty good.
The last step for my workflow would be to self host an IMAP server that will index the POP3 mailbox, and expose it read-only (without SMTP) through a webmail app, for archival and search only. I may have to look at Piler. The quirk here is that the Claws mailbox format is slightly different from IMAP, it's very similar to mbox but not identical, will have to see if any IMAP server will accept it.
Thunderbird is no go unfortunately, its main box format is to keep all messages on one big file instead of individual files, which complicates things a lot.