Thunderbird 3 in a business setup

For a number of years we've used Thunderbird as the mail client of choice. It has a good feature set and does IMAP well. However, the advent of Thunderbird 3 adds a little issue.

To reduce the size of roaming profiles (and therefore speed up login and log out) we have thunderbird profiles mapped to a directory within the users' login directory - and hence stored on the server. Thunderbird 3, automatically downloads copies of all the users' IMAP email to make both an offline cache and to index the mail for the new search facility.

This would mean that the server space used by the Thunderbird profile would grow considerably.

So there's two choices. Either disable the global indexing and off line store or put the off line store somewhere else.

As the new search is a good tool, I've opted for the second - though I'll leave it up to the users as to whether they use the search tool or not.

The solution here is to add a couple of files to each machine running Thunderbird:

Firstly in the defaults/pref/ folder (/usr/lib/thunderbird-3.0.4/defaults/pref on linux , C:\Program Files\Thunderbird\defaults\pref on windows) I add a little file custom.js

/* Custom local config */

pref("general.config.obscure_value", 0);
pref("general.config.filename", "custom.cfg");

The first of those settings means that you can write your config file in plain ASCII rather than a strange encoding and the second is the name of the custom config.


Next, the custom config goes in /usr/lib/thunderbird-3.0.4 for linux or C:\Program Files\Thunderbird for windows

//
/* This will disable indexation by default - can be enabled per user */
defaultPref("mailnews.database.global.indexer.enabled", false);

/* This will disable offline download by default */
defaultPref("mail.server.default.offline_download", false);

/* This will parse the prefs.js and set the directory for "offline_download" for each IMAP account */

if(getenv("USER") != "") {
 // *NIX settings
 var env_user    = getenv("USER");
 var env_home    = getenv("HOME");
 var env_os = "linux";
} else {
 // Windows settings
 var env_user    = getenv("USERNAME");
 var env_home    = getenv("HOMEPATH");
 var env_os = "windows"
}

if (getPref("mail.accountmanager.accounts")) {

  var listExistingAccounts = getPref("mail.accountmanager.accounts");
  var arrayExistingAccounts = listExistingAccounts.split(',');

  for (var i=0; i < arrayExistingAccounts.length; i++){
    var serverFromAccount = getPref("mail.account." + arrayExistingAccounts[i] + ".server");
    var configType = getPref("mail.server." + serverFromAccount + ".type");
    if (configType == "imap") {
      defaultPref("mail.server." + serverFromAccount + ".offline_download", false);
      lockPref("mail.server." + serverFromAccount + ".server_sub_directory", "INBOX.");
      var serverName = getPref("mail.server." + serverFromAccount + ".hostname");
      var userName = getPref("mail.server." + serverFromAccount + ".userName");
      if (env_os == "windows") {
        lockPref("mail.server." + serverFromAccount + ".directory", "[LocalAppData]Thunderbird/" + serverName + "/" + userName);
        lockPref("mail.server." + serverFromAccount + ".directory-rel", "[LocalAppData]Thunderbird/" + serverName + "/" + userName);
      }
      if (env_os == "linux") {
        lockPref("mail.server." + serverFromAccount + ".directory", "/opt/mailcache/" + env_user + "/" + serverName + "/" + userName);
        lockPref("mail.server." + serverFromAccount + ".directory-rel", "/opt/mailcache/" + env_user + "/" + serverName + "/" + userName);
      }
    }
  }
}

I also take advantage of this to set the server directory for the IMAP folders to INBOX. as that gives the better layout of mailboxes in Thunderbird when talking to a Courier IMAP server.

On a Windows machine, I set the users' offline cache to being in the Local Settings part of their profile - this keeps it safe to the user but avoids it being synced to the server.

For a Linux machine, I set up an area called /opt/mailcache with the same kind of permissions as /tmp i.e. globally writable but with the sticky bit set. This has the result that individual users can't get at each others mail cache.

In our LTSP setup, /opt/mailcache will be excluded from the backup as there is no need to back this stuff up as it is simply a copy of what is already in the mailbox.