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Self-host a personal calendar and address book using Radicale

Last edited on 2021-07-01 • Tagged under  #nginx   #network   #linux 

CalDAV and CardDAV are open protocols for sharing a calendar and address book respectively between devices. Radicale is a self-hosted CalDAV and CardDAV server that, as per their website,:

  • Shares calendars and contact lists through CalDAV, CardDAV and HTTP.
  • Supports events, todos, journal entries and business cards.
  • Works out-of-the-box, no complicated setup or configuration required.
  • Can limit access by authentication.
  • Can secure connections with TLS.
  • Works with many CalDAV and CardDAV clients.
  • Stores all data on the file system in a simple folder structure.
  • Can be extended with plugins.
  • Is GPLv3-licensed free software.

Sounds good! Let's get it setup.

Install and configure

Install ...

$ python3 -m pip install --upgrade radicale

Make directories ...

$ mkdir -p ~/.config/radicale
$ mkdir -p ~/.var/lib/radicale/collections
$ sudo mkdir /etc/radicale

Setup user authentication for <username> (choose a name) using htpasswd ...

$ sudo apt install apache2-utils
$ sudo htpasswd -c /etc/radicale/users <username>

Create ~/.config/radicale/config. Example:

[server]
# access over the network
hosts = 0.0.0.0:5232, [::]:5232
max_connections = 20
# 100 Megabyte
max_content_length = 100000000
# 30 seconds
timeout = 30

[storage]
filesystem_folder = ~/.var/lib/radicale/collections

[auth]
type = htpasswd
htpasswd_filename = /etc/radicale/users
# encryption method used in the htpasswd file
htpasswd_encryption = md5
# Average delay after failed login attempts in seconds
delay = 1

Run as a service

Run as a service with systemd as a user. Create directory ...

$ mkdir ~/.config/systemd/user

Create file ~/.config/systemd/user/radicale.service. Example:

[Unit]
Description=A simple CalDAV (calendar) and CardDAV (contact) server

[Service]
ExecStart=/usr/bin/env python3 -m radicale
Restart=on-failure

[Install]
WantedBy=default.target

At this point, a problem might arise. When I went to enable the service ... 

$ systemctl --user enable radicale
Failed to connect to bus: No such file or directory

In my case, this was because the XDG_RUNTIME_DIR and DBUS_SESSION_BUS_ADDRESS environment variables were missing.

If this rears up and bites you, run the following commands and test ...

$ export XDG_RUNTIME_DIR="/run/user/$UID"
$ export DBUS_SESSION_BUS_ADDRESS="unix:path=${XDG_RUNTIME_DIR}/bus"
$ systemctl --user status

It works! See: Managing another user's systemd units

To make this fix permanent, modify /etc/ssh/sshd_config and set UsePAM no to UsePAM yes (which in Debian 10 is the default setting).

Enable and start the service ...

$ systemctl --user enable --now radicale

Check the status ...

$ systemctl --user status radicale
$ journalctl --user --unit radicale.service

Login to the web interface at http://<server-ip-address>:5232 with the newly-created username and password.

Click on Create new addressbook or calendar and I create an empty calendar and a empty address book; each outputs a link to URL: http://server-ip-address>:5232/<username>/<string>/.

Use Nginx as a reverse proxy

First, see "Nginx web server" to install and configure Nginx, an open-source, high performance, lightweight HTTP and reverse proxy server. Nginx sits in front of Radicale as the proxy, removing the location from the URL path that is forwarded to Radicale.

Example: An nginx configuration in /etc/nginx/conf.d/my-website.conf that uses Duck DNS for Dynamic DNS and SSL via a self-signed certificate ...

server {
    listen 80;
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name my-subdomain-name.duckdns.org;

    ssl_certificate /etc/ssl/certs/nginx-server-selfsigned.crt;
    ssl_certificate_key /etc/ssl/private/nginx-server-selfsigned.key;

    location / {
        root   /home/my-username/html;
        index  index.html index.htm;
    }

    location /radicale/ { # The trailing / is important!
        proxy_pass        http://localhost:5232/; # The / is important!
        proxy_set_header  X-Script-Name /radicale;
	    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  X-Remote-User $remote_user;
        proxy_set_header  Host $http_host;
	    proxy_pass_header Authorization;
    }
}

Restart nginx and radicale ...

$ sudo systemctl restart nginx
$ systemctl --user restart radicale

Navigate to https://my-subdomain-name.duckdns.org:port-number/radicale/ and confirm the Radicale login is displayed.

See Radicale Reverse Proxy for more options.

Add a client: Thunderbird

Recent versions of the Thunderbird email client now include a built-in calendar. Click on the calendar tab icon in the upper right corner to open.

In the calendar tab, click on the + in the left calendar sidebar and add a new calendar on the network with CalDAV. Enter the URL for the Radicale-hosted calendar. Thunderbird's calendar populates with data.

For the address book, install the CardBook add-on. Click on the CardBook tab icon in the upper right corner to open.

In the address book column, right-click and choose New Addressbook, select Remote for location, CardDav, and enter the URL for the Radicale-hosted address book. After setup, click and drag Thunderbird's existing contacts into the new address book.

Add a client: DAVx5

DAVx5 is a CalDAV/CardDAV synchronization client for Android, which I install via F-Droid.

After setting up an account with your Radicale username and URL, the calendar and address book are synced to the phone, and viewable in your Calendar and Contacts apps.

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