maildir_commander

maildir commander is a wrapper around maildir-utils to make it more versatile. mu server is already state-less; however, it cannot be used by more than one client at a time. maildir_commander runs one instance of mu server in the background and make it an always-on daemon, so mu4e, command-line clients and web clients can share the same underlying mu server instance through maildir_commander.

dependency

the server

maildir_commander can be used as a dependancy library of a larger application or a stand-alone application. In the stand-aline mode, just run the release. It will run mu server in the background and communicate with it through a port. All functionalities of mu server are exported as erlang APIs via the mc_mu_api module.

The mu server will be ran on demand. If there is nothing to do for some time (60 seconds by default) the mu server will be shut dowm to save memory. The on/off of mu server is automatic and user does not need to care about it except some small startup latency every once in a while.

the local socket

maildir_commander will also listen on a Unix domain socket $HOME/.mc_server_sock. The socket, once connected, behave exactly like mu server. All commands are passed through to the shared mu server instance, with the only exception of the quit command, which is locally handled to close the socket while leaving the server up. so:

$ socat UNIX-CONNECT:$HOME/.mc_server_sock -

behave exactly like mu server, except now you can run multiple instances. I have a shell script in scripts/mc that can be a drop in repleacement of mu (now only mc server is supported, in the future I plan to re-implement more mu client side sub-commands). If you run maildir_commander as a daemon, mu will not work. To continue using mu4e, you would have to configure mu4e to use mc as the alternative mu binary.

the watcher

maildir_commander also has a watcher that watchs the Maildir for new mails and add to the mu database automatically. Given that maildir_commander always do a full index on startup, there is little reason to run indexing yourself anymore.

The watcher will also move new mails to the cur dir as per maildir standard. Therefore, you must ensure that the IMAP server is not getting in its way. If you are using exim, please make sure the local delivery is done via maildir_home, not with a IMAP specific LDA such as dovecot_delivery. Also please turn off the auto movement of new mails in your IMAP server. In dovecot, it is controlled in /etc/dovecot/conf.d/10-mail.conf with a line as:

maildir_empty_new = no

Dovecot should still work, just less efficiently.

Related works

maildir_commander is meant to be the lower layer of more sofisticated MUAs such as a web client to run along side with the command line client and mu4e. In most cases you want to install LIV, which is a webmail client built on top of this package..