Android Contacts/Calendar Sync without Google

On Android, you are supposed to sync contacts and calendar to the (Google) cloud. But what if you dont trust the cloud? Would rather sync to your home computer/laptop only? There are a few options; most require Windows and an additional app on the phone. And you can always setup your own Exchange or WebDAV server, even if this is quite some effort.

I first locally synced my HTC Desire to Outlook via HTC Sync and then my travel phone, an LG P350 optimus, via Android Sync Manager Wi-Fi. My Galaxy Nexus (Android 4.0) got Local Sync until it began to behave suspiciously on Windows. Since then, I have used DavX5 with radicale on an WSGI-enabled Apache web server.

Sync with WebDAV (2020)

For quite some time, it was difficult to get Android phones synced to non-Windows applications. Fortunately people have developed standard-based sync e.g. with WebDAV, which works over HTTP(s). On my Linux server, I installed radicale, a Python app that writes vcf (contacts) and ics (calendar) text files to the local file system, where I can version them with git and include them in my backup/restore routine.

To access radicale from the network, I added it into my Apache web server, using WSGI as Apache-Python bridge. On Android clients, DavX5 connects to Apache. On Linux, Thunderbird with CardBook (contacts) and Lightning (calendar) add-ons has cross-platform Apache access.

Radicale 3.0

We start with some insights on radicale [tutorial]:

• Radicale is a python app
• Does not start as daemon when going through apache2 and wsgi
• WSGI file is just a Python file
• If you have other webapps, the radicale directory should be under /var/www/ too
• For a web interface, at least radicale 2.1.0 is required

apt-get install python3-pip python3-bcrypt python3-passlib
python3 -m pip install --upgrade radicale # installs radicale3 (2020)
mkdir /etc/radicale

# directories:
#   /etc/radicale
#   /usr/local/lib/python3.7/dist-packages/radicale/

nano -w /etc/radicale/config.apache
    [server]
    hosts = 0.0.0.0:5232
    ssl = True
    certificate = /etc/ssl/dyndns.mydomain.de/myhost.crt
    key = /etc/ssl/dyndns.mydomain.de/myhost.key

    [auth]
    type = remote_user
    htpasswd_filename = /etc/radicale/htpasswd.cfg
    htpasswd_encryption = bcrypt

    [storage]
    filesystem_folder = /opt/radicale/

    [logging]
    level = warning

# create HT passwd, used by apache too:
cd /etc/radicale
htpasswd -cB htpasswd.cfg myuser

# create data directory, for www-data user:
mkdir /opt/radicale
chown -R www-data.www-data /opt/radicale

Time for a test run with a browser of your choice! Here you will also create the contact/calendar files and directories for the first time.

# as root:
su www-data
python3 -m radicale
# will hang and display log; start the browser now
# ctrl-c on "python3 -m radicale" to stop server

https://server.local:5232/
# create contacts and calendar in web interface
# to compensate for your short password, they have long coded names

# rename accounts (there goes the extra security):
cd /opt/radicale/data/collections
mv 65435459-6e51-2543-b805-7cb54378768f con
mv be5a2453-8645-ebff-cfaf-e6b686565a2b cal
# reload web interface

... and once we have this, we can use git for versioning.

# git control:
cd /opt/radicale/collection-root
nano -w .gitignore
    .Radicale.cache
    .Radicale.lock
    .Radicale.tmp-*

git init .
git add .
git commit -a -m "Initial upload."

Make sure that port 5232 is never reachable from the outside, though we will not use it because Apache is routed locally, not via daemon.

Apache to Radicale

Next, we connect radicale to Apache.

apt-get install libapache2-mod-wsgi-py3

nano -w /etc/apache2/sites-available/myhost.conf
    WSGIDaemonProcess radicale user=www-data group=www-data threads=1
    WSGIScriptAlias /radicale /var/www/dyndns.mydomain.de/radicale/radicale.wsgi
    WSGIProcessGroup radicale
    <Location /radicale>
        AllowOverride None
        AuthType basic
        AuthName "dyndns.mydomain.de"
        AuthUserFile /etc/radicale/htpasswd.cfg
        Require user myuser
        SSLRequireSSL
    </Location>

su www-data
nano -w /var/www/dyndns.mydomain.de/radicale/radicale.wsgi
    import os
    from radicale import Application, config, log
    config_paths = [('/etc/radicale/config.apache', False)]
    configuration = config.load(config_paths)
    application = Application(configuration)

chown -R www-data.www-data /var/www/dyndns.mydomain.de

... and after a systemctl restart apache2 whip out your browser again:

https://dyndns.mydomain.de/radicale/
clear && tail -f /var/log/apache2/access.log

... and watch the console to see your accesses.

DavX5

Get DavX5 for free on F-Droid or give them a 5€ donation on GPlay. The configuration is very short:

new account
    base url: https://dyndns.mydomain.de/radicale
    username: myuser

You might want to prod around in the settings to avoid over-eager syncing behavior. After that, press the sync button, ssh onto your server and watch the vcf and ics files come in.

Thunderbird

And on we go for radicale clients on the Linux desktop.

# lightning for calendar
apt-get install xul-ext-lightning

# cardbook for contacts
Tools -> Addons-> Search on addons.thunderbird.net -> cardbook

# sync contacts:
Addons -> Cardbook (Shift+Ctrl+B)
    left area -> RMB, new address book
    Remote, CardDAV, url: https://dyndns.mydomain.de/radicale/myuser/con/, Validate

# sync calendar:
Events and Tasks -> Calendar (Shift+Ctrl+C)
    left area -> RMB, new calendar
    Network, CalDAV, location: https://dyndns.mydomain.de/radicale/myuser/cal/

Isnt that nice? Just what I wanted, cross-platform sync on my own server and my own terms.

Conclusion

Android sync is still a wild ride, as evidenced by the effort required to get rid of Google even a little bit. Hopefully the information above could make you fractionally more knowledgeable in that regard. Always strive for freedom, and have a good day!