[[!img notmuch-logo.png alt="Notmuch logo" class="left"]] #Using notmuch remotely# ##Why?## It is hard to keep nomuch tags in sync across multiple instances of notmuch, on multiple computers. Though you can do this with "notmuch dump" and "notmuch restore", it is often preferable to be able to use notmuch on a remote computer as if it were present on a local computer. The following guidelines show how I have accomplished this. It isn't perfect, but it works pretty well, and allows me to access notmuch on my home computer, using only an emacs client on my netbook or work computer, a trivial shell script, a few settings in my .emacs, and ssh. Note that this is all something of a hack, and future versions of notmuch will likely make all of these steps much more transparent. I'll note particularly which things should become unneccessary with future version. At the moment though, this does work, and might enable some of you to use notmuch away from your primary computer. ##What you will need## You will need to have the following items in place: 1. a working notmuch on one computer (let's call that computer "server"). The notmuch should be at least version 0.2. 2. a working notmuch emacs interface on another computer (let's call that computer "client") 3. password-free login (public key authentication) from client to server. [Here](http://sial.org/howto/openssh/publickey-auth/) is a good page on how to set it up. 4. a reasonably fast connection. (This isn't really *neccessary*, but if your connection is too slow, this won't be very pleasant to use, and certainly won't seem transparent.) ##Write a wrapper shell script## /!\ Now that notmuch (>=0.5) allows for "raw" downloading of messages, a lot of the hacks in the older script, posted in 2010, are no longer necessary. Now we will need to write a simple shell script that does two things: 1. replaces the call to the notmuch binary with a call to notmuch over ssh. 2. caches messages when the entire raw message is downloaded. This avoids the need to constantly download large attachments over and over. (NB: this just checks to see if a message with the same id has already been cached. If you delete an attachment on the server, that could lead to an out-of-date cache. It would probably make more sense in the future to concatenate a hash of the message id and a hash of the message.) Note that this shell script also pauses briefly after every message entries. This is currently necessary so that the emacs process-filter doesn't chop off messages. It's an obvious hack, and hopefully won't be necessary in the furture. #!/usr/bin/env bash SSH_BIN="/path/to/ssh/on/client" USER="user_name" SSH_HOST="server_name" NOTMUCH_REMOTE_BIN="/path/to/notmuch/on/server" CACHE="${HOME}/.notmuch-cache.d" hash_name () { echo -n ${1} | sha1sum | awk '{print $1}' } check_for_file_name () { [ -f "${CACHE}/${1}" ] } notmuch_run () { [ -d "${CACHE}" ] || mkdir -p "${CACHE}" CMD=$1 shift # we need to a little sanitizing of msg ids so the shell # doesn't mangle them ARGS=`echo $@ | sed 's/[\\$\\*\\!]/\\\&/g'` $SSH_BIN $USER@$SSH_HOST $NOTMUCH_REMOTE_BIN ${CMD} ${ARGS} } notmuch_search () { notmuch_run search $@ | while read line; do sleep 0.02 echo "${line}" done } notmuch_show () { if [ ${1} = "--format=raw" ]; then hashed=`hash_name ${2}` check_for_file_name ${hashed} || notmuch_run show --format=raw ${2} > "${CACHE}/${hashed}" cat "${CACHE}/${hashed}" else notmuch_run show $@ fi } if [ ${1} = "search" ]; then shift notmuch_search $@ elif [ ${1} = "show" ]; then shift notmuch_show $@ else notmuch_run $@ fi Save this to a file, "remote-notmuch.sh", in your path. Now you can run "remote-notmuch.sh new". You can call the script anything you like. I actually have $HOME/bin/notmuch linked to that script, so I can transparent usage. (Since I run "new" from an emacs keybinding, I've never bothered with this renaming.) ##Configure your emacs client## The only thing you need to do is tell your emacs client to use the script. Add the following to your .emacs (this is on your client machine): (setq notmuch-command "/path/to/your/remote-notmuch.sh") ##A tip to speed things up## If you have openssh >= 0.4, you can make use of the "ControlMaster" feature. This allows you to reuse an existing connection. Therefore if you keep a connection open, you won't have to authenticate every time. Add the following to your ~/.ssh/config file: Host server_name ControlMaster auto ControlPath ~/.ssh/master-%r@%h:%p You can also se the Host to "*", if you want to use it for all connections. I usually have an interactive ssh connection to my home computer open, so I don't need to do anything more. But if not, you can always run: ssh -Nf server_name which will open up a background connection, which you can then reuse for all of your notmuch commands. ##Problems## Some things won't work perfectly, and there might be some unexpected mismatches between normal usage and this sort of usage. If you're using this approach and run into any problems, please feel free to list them here. And, of course, if you improve on any of these approaches, please do edit this page and let people know!