Radicale/DOCUMENTATION.md

Documentation

Getting started

About Radicale

Radicale is a small but powerful CalDAV (calendars, to-do lists) and CardDAV (contacts) server, that:

• 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.
• Offers flexible authentication options.
• Can limit access by authorization.
• 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.

Installation

Check

• Tutorials
• Documentation
• Wiki on GitHub
• Discussions on GitHub
• Open and already Closed Issues on GitHub

What's New?

Read the Changelog on GitHub.

Tutorials

Simple 5-minute setup

You want to try Radicale but only have 5 minutes free in your calendar? Let's go right now and play a bit with Radicale!

The server, configured with settings from this section, only binds to localhost (i.e. it is not reachable over the network), and you can log in with any username and password. When everything works, you may get a local client and start creating calendars and address books. If Radicale fits your needs, it may be time for some basic configuration to support remote clients and desired authentication type.

Follow one of the chapters below depending on your operating system.

Linux / *BSD

Hint: instead of downloading from PyPI, look for packages provided by your distribution. They contain also startup scripts integrated into your distributions, that allow Radicale to run daemonized.

First, make sure that python 3.9 or later and pip are installed. On most distributions it should be enough to install the package python3-pip.

as normal user

Recommended only for testing - open a console and type:

# Run the following command to only install for the current user
python3 -m pip install --user --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz

If install is not working and instead error: externally-managed-environment is displayed, create and activate a virtual environment in advance.

python3 -m venv ~/venv
source ~/venv/bin/activate

and try to install with

python3 -m pip install --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz

Start the service manually, data is stored only for the current user

# Start, data is stored for the current user only
python3 -m radicale --storage-filesystem-folder=~/.var/lib/radicale/collections --auth-type none

as system user (or as root)

Alternatively, you can install and run as system user or as root (not recommended):

# Run the following command as root (not recommended) or non-root system user
# (the later may require --user in case dependencies are not available system-wide and/or virtual environment)
python3 -m pip install --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz

Start the service manually, with data stored in a system folder under /var/lib/radicale/collections:

# Start, data is stored in a system folder (requires write permissions to /var/lib/radicale/collections)
python3 -m radicale --storage-filesystem-folder=/var/lib/radicale/collections --auth-type none

Windows

The first step is to install Python. Go to python.org and download the latest version of Python 3. Then run the installer. On the first window of the installer, check the "Add Python to PATH" box and click on "Install now". Wait a couple of minutes, it's done!

Launch a command prompt and type:

python -m pip install --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz
python -m radicale --storage-filesystem-folder=~/radicale/collections --auth-type none

Common

Success!!! Open http://localhost:5232 in your browser! You can log in with any username and password as no authentication is required by example option --auth-type none. This is INSECURE, see Configuration/Authentication for more details.

Just note that default configuration for security reason binds the server to localhost (IPv4: 127.0.0.1, IPv6: ::1). See Addresses and Configuration/Server for more details.

Basic Configuration

Installation instructions can be found in the simple 5-minute setup tutorial.

Radicale tries to load configuration files from /etc/radicale/config and ~/.config/radicale/config. Custom paths can be specified with the --config /path/to/config command line argument or the RADICALE_CONFIG environment variable. Multiple configuration files can be separated by : (resp. ; on Windows). Paths that start with ? are optional.

You should create a new configuration file at the desired location. (If the use of a configuration file is inconvenient, all options can be passed via command line arguments.)

All configuration options are described in detail in the Configuration section.

Authentication

In its default configuration since version 3.5.0, Radicale rejects all authentication attempts by using config option type = denyall (introduced with 3.2.2) as default until explicitly configured.

Versions before 3.5.0 did not check usernames or passwords at all, unless explicitly configured. If such a server is reachable over a network, you should change this as soon as possible.

First a users file with all usernames and passwords must be created. It can be stored in the same directory as the configuration file.

The secure way

The users file can be created and managed with htpasswd:

Note: some OSes or distributions contain outdated versions of htpasswd (< 2.4.59) without support for SHA-256 or SHA-512 (e.g. Ubuntu LTS 22). In these cases, use htpasswd's command line option -B for the bcrypt hash method (recommended), or stay with the insecure (not recommended) MD5 (default) or SHA-1 (command line option -s).

Note: support of SHA-256 and SHA-512 was introduced with 3.1.9

# Create a new htpasswd file with the user "user1" using SHA-512 as hash method
$ htpasswd -5 -c /path/to/users user1
New password:
Re-type new password:
# Add another user
$ htpasswd -5 /path/to/users user2
New password:
Re-type new password:

Authentication can be enabled with the following configuration:

[auth]
type = htpasswd
htpasswd_filename = /path/to/users
htpasswd_encryption = autodetect

The simple but insecure way

Create the users file by hand with lines containing the username and password separated by :. Example:

user1:password1
user2:password2

Authentication can be enabled with the following configuration:

[auth]
type = htpasswd
htpasswd_filename = /path/to/users
# encryption method used in the htpasswd file
htpasswd_encryption = plain

Addresses

The default configuration binds the server to localhost. It cannot be reached from other computers. This can be changed with the following configuration options (IPv4 and IPv6):

[server]
hosts = 0.0.0.0:5232, [::]:5232

Storage

Data is stored in the folder /var/lib/radicale/collections. The path can be changed with the following configuration:

[storage]
filesystem_folder = /path/to/storage

Security: The storage folder shall not be readable by unauthorized users. Otherwise, they can read the calendar data and lock the storage. You can find OS dependent instructions in the Running as a service section.

Limits

Radicale enforces limits on the maximum number of parallel connections, the maximum file size (important for contacts with big photos) and the rate of incorrect authentication attempts. Connections are terminated after a timeout. The default values should be fine for most scenarios.

[server]
max_connections = 20
# 100 Megabyte
max_content_length = 100000000
# 30 seconds
timeout = 30

[auth]
# Average delay after failed login attempts in seconds
delay = 1

Running as a service

The method to run Radicale as a service depends on your host operating system. Follow one of the chapters below depending on your operating system and requirements.

Linux with systemd system-wide

Recommendation: check support by Linux Distribution Packages instead of manual setup / initial configuration.

Create the radicale user and group for the Radicale service by running (as root:

useradd --system --user-group --home-dir / --shell /sbin/nologin radicale

The storage folder must be made writable by the radicale user by running (as root):

mkdir -p /var/lib/radicale/collections && chown -R radicale:radicale /var/lib/radicale/collections

If a dedicated cache folder is configured (see option filesystem_cache_folder), it also must be made writable by radicale. To achieve that, run (as root):

mkdir -p /var/cache/radicale && chown -R radicale:radicale /var/cache/radicale

Security: The storage shall not be readable by others. To make sure this is the case, run (as root):

chmod -R o= /var/lib/radicale/collections

Create the file /etc/systemd/system/radicale.service:

[Unit]
Description=A simple CalDAV (calendar) and CardDAV (contact) server
After=network.target
Requires=network.target

[Service]
ExecStart=/usr/bin/env python3 -m radicale
Restart=on-failure
User=radicale
# Deny other users access to the calendar data
UMask=0027
# Optional security settings
PrivateTmp=true
ProtectSystem=strict
ProtectHome=true
PrivateDevices=true
ProtectKernelTunables=true
ProtectKernelModules=true
ProtectControlGroups=true
NoNewPrivileges=true
ReadWritePaths=/var/lib/radicale/
# Replace with following in case dedicated cache folder should be used
#ReadWritePaths=/var/lib/radicale/ /var/cache/radicale/

[Install]
WantedBy=multi-user.target

In this system-wide implementation, Radicale will load the configuration from the file /etc/radicale/config.

To enable and manage the service run:

# Enable the service
$ systemctl enable radicale
# Start the service
$ systemctl start radicale
# Check the status of the service
$ systemctl status radicale
# View all log messages
$ journalctl --unit radicale.service

Linux with systemd as a user

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

[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

In this user-specific configuration, Radicale will load the configuration from the file ~/.config/radicale/config. You should set the configuration option filesystem_folder in the storage section to something like ~/.var/lib/radicale/collections.

To enable and manage the service run:

# Enable the service
$ systemctl --user enable radicale
# Start the service
$ systemctl --user start radicale
# Check the status of the service
$ systemctl --user status radicale
# View all log messages
$ journalctl --user --unit radicale.service

Windows with "NSSM - the Non-Sucking Service Manager"

First install NSSM and start nssm install in a command prompt. Apply the following configuration:

• Service name: Radicale
• Application
  • Path: C:\Path\To\Python\python.exe
  • Arguments: --config C:\Path\To\Config
• I/O redirection
  • Error: C:\Path\To\Radicale.log

Security: Be aware that the service runs in the local system account, you might want to change this. Managing user accounts is beyond the scope of this manual. Also, make sure that the storage folder and log file is not readable by unauthorized users.

The log file might grow very big over time, you can configure file rotation in NSSM to prevent this.

The service is configured to start automatically when the computer starts. To start the service manually open Services in Computer Management and start the Radicale service.

Reverse Proxy

When a reverse proxy is used, and Radicale should be made available at a path below the root (such as /radicale/), then this path must be provided via the X-Script-Name header (without a trailing /). The proxy must remove the location from the URL path that is forwarded to Radicale. If Radicale should be made available at the root of the web server (in the nginx case using location /), then the setting of the X-Script-Name header should be removed from the example below.

Example nginx configuration extension:

See also for latest examples: https://github.com/Kozea/Radicale/tree/master/contrib/nginx/

location /radicale/ { # The trailing / is important!
    proxy_pass        http://localhost:5232;
    proxy_set_header  X-Script-Name /radicale;
    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header  X-Forwarded-Host $host;
    proxy_set_header  X-Forwarded-Port $server_port;
    proxy_set_header  X-Forwarded-Proto $scheme;
    proxy_set_header  Host $http_host;
    proxy_pass_header Authorization;
}

Example Caddy configuration extension:

See also for latest examples: https://github.com/Kozea/Radicale/tree/master/contrib/caddy/

handle_path /radicale/* {
    uri strip_prefix /radicale
    reverse_proxy localhost:5232 {
    }
}

Example Apache configuration extension:

See also for latest examples: https://github.com/Kozea/Radicale/tree/master/contrib/apache/

RewriteEngine On
RewriteRule ^/radicale$ /radicale/ [R,L]

<Location "/radicale/">
    ProxyPass        http://localhost:5232/ retry=0
    ProxyPassReverse http://localhost:5232/
    RequestHeader    set X-Script-Name /radicale
    RequestHeader    set X-Forwarded-Port "%{SERVER_PORT}s"
    RequestHeader    set X-Forwarded-Proto expr=%{REQUEST_SCHEME}
    <IfVersion >= 2.4.40>
    Proxy100Continue Off
    </IfVersion>
</Location>

Example Apache .htaccess configuration:

DirectoryIndex disabled
RewriteEngine On
RewriteRule ^(.*)$ http://localhost:5232/$1 [P,L]

# Set to directory of .htaccess file:
RequestHeader set X-Script-Name /radicale
RequestHeader set X-Forwarded-Port "%{SERVER_PORT}s"
RequestHeader unset X-Forwarded-Proto
<If "%{HTTPS} =~ /on/">
RequestHeader set X-Forwarded-Proto "https"
</If>

Example lighttpd configuration:

server.modules += ( "mod_proxy" , "mod_setenv", "mod_rewrite" )

$HTTP["url"] =~ "^/radicale/" {
  proxy.server = ( "" => (( "host" => "127.0.0.1", "port" => "5232" )) )
  proxy.header = ( "map-urlpath" => ( "/radicale/" => "/" ))

  setenv.add-request-header = (
    "X-Script-Name" => "/radicale",
    "Script-Name" => "/radicale",
  )
  url.rewrite-once = ( "^/radicale/radicale/(.*)" => "/radicale/$1" )
}

Be reminded that Radicale's default configuration enforces limits on the maximum number of parallel connections, the maximum file size and the rate of incorrect authentication attempts. Connections are terminated after a timeout.

Manage user accounts with the reverse proxy

Set the configuration option type in the auth section to http_x_remote_user. Radicale uses the username provided in the X-Remote-User HTTP header and disables its internal HTTP authentication.

Example nginx configuration:

location /radicale/ {
    proxy_pass           http://localhost:5232/;
    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;
    auth_basic           "Radicale - Password Required";
    auth_basic_user_file /etc/nginx/htpasswd;
}

Example Caddy configuration:

handle_path /radicale/* {
    uri strip_prefix /radicale
    basicauth {
        USER HASH
    }
    reverse_proxy localhost:5232 {
        header_up X-Script-Name /radicale
        header_up X-remote-user {http.auth.user.id}
    }
}

Example Apache configuration:

RewriteEngine On
RewriteRule ^/radicale$ /radicale/ [R,L]

<Location "/radicale/">
    AuthType     Basic
    AuthName     "Radicale - Password Required"
    AuthUserFile "/etc/radicale/htpasswd"
    Require      valid-user

    ProxyPass        http://localhost:5232/ retry=0
    ProxyPassReverse http://localhost:5232/
    <IfVersion >= 2.4.40>
    Proxy100Continue Off
    </IfVersion>
    RequestHeader    set X-Script-Name /radicale
    RequestHeader    set X-Remote-User expr=%{REMOTE_USER}
</Location>

Example Apache .htaccess configuration:

DirectoryIndex disabled
RewriteEngine On
RewriteRule ^(.*)$ http://localhost:5232/$1 [P,L]

AuthType     Basic
AuthName     "Radicale - Password Required"
AuthUserFile "/etc/radicale/htpasswd"
Require      valid-user

# Set to directory of .htaccess file:
RequestHeader set X-Script-Name /radicale
RequestHeader set X-Remote-User expr=%{REMOTE_USER}

Security: Untrusted clients should not be able to access the Radicale server directly. Otherwise, they can authenticate as any user by simply setting related HTTP header. This can be prevented by listening to the loopback interface only or local firewall rules.

Secure connection between Radicale and the reverse proxy

SSL certificates can be used to encrypt and authenticate the connection between Radicale and the reverse proxy. First you need to generate a certificate for Radicale and a certificate for the reverse proxy. The following commands generate self-signed certificates. You will be asked to enter additional information about the certificate, these values do not really matter, and you can keep the defaults.

openssl req -x509 -newkey rsa:4096 -keyout server_key.pem -out server_cert.pem \
        -nodes -days 9999
openssl req -x509 -newkey rsa:4096 -keyout client_key.pem -out client_cert.pem \
        -nodes -days 9999

Use the following configuration for Radicale:

[server]
ssl = True
certificate = /path/to/server_cert.pem
key = /path/to/server_key.pem
certificate_authority = /path/to/client_cert.pem

If you are using the Let's Encrypt Certbot, the configuration should look similar to this:

[server]
ssl = True
certificate = /etc/letsencrypt/live/{Your Domain}/fullchain.pem
key = /etc/letsencrypt/live/{Your Domain}/privkey.pem

Example nginx configuration:

location /radicale/ {
    proxy_pass https://localhost:5232/;
    ...
    # Place the files somewhere nginx is allowed to access (e.g. /etc/nginx/...).
    proxy_ssl_certificate         /path/to/client_cert.pem;
    proxy_ssl_certificate_key     /path/to/client_key.pem;
}

WSGI Server

Radicale is compatible with the WSGI specification.

A configuration file can be set with the RADICALE_CONFIG environment variable, otherwise no configuration file is loaded and the default configuration is used.

Example uWSGI configuration:

[uwsgi]
http-socket = 127.0.0.1:5232
processes = 8
plugin = python3
module = radicale
env = RADICALE_CONFIG=/etc/radicale/config

Example Gunicorn configuration:

gunicorn --bind '127.0.0.1:5232' --env 'RADICALE_CONFIG=/etc/radicale/config' \
         --workers 8 radicale

Manage user accounts with the WSGI server

Set the configuration option type in the auth section to remote_user. This way Radicale uses the username provided by the WSGI server and disables its internal authentication over HTTP.

Versioning collections with Git

This tutorial describes how to keep track of all changes to calendars and address books with git (or any other version control system).

The repository must be initialized in the collection base directory of the user running radicale daemon.

## assuming "radicale" user is starting "radicale" service
# change to user "radicale"
su -l -s /bin/bash radicale

# change to collection base directory defined in [storage] -> filesystem_folder
#  assumed here /var/lib/radicale/collections
cd /var/lib/radicale/collections

# initialize git repository
git init

# set user and e-mail, here minimum example
git config user.name "$USER"
git config user.email "$USER@$HOSTNAME"

# define ignore of cache/lock/tmp files
cat <<'END' >.gitignore
.Radicale.cache
.Radicale.lock
.Radicale.tmp-*
END

The configuration option hook in the storage section must be set to the following command:

git add -A && (git diff --cached --quiet || git commit -m "Changes by \"%(user)s\"")

The command gets executed after every change to the storage and commits the changes into the git repository.

Log of git can be investigated using

su -l -s /bin/bash radicale
cd /var/lib/radicale/collections
git log

In case of problems, make sure you run radicale with --debug switch and inspect the log output. For more information, please visit section on logging.

Reason for problems can be

• SELinux status -> check related audit log
• problematic file/directory permissions
• command is not fond or cannot be executed or argument problem

Documentation

Configuration

Radicale can be configured with a configuration file or with command line arguments.

Configuration files have INI-style syntax comprising key-value pairs grouped into sections with section headers enclosed in brackets.

An example configuration file looks like:

[server]
# Bind all addresses
hosts = 0.0.0.0:5232, [::]:5232

[auth]
type = htpasswd
htpasswd_filename = ~/.config/radicale/users
htpasswd_encryption = autodetect

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

Radicale tries to load configuration files from /etc/radicale/config and ~/.config/radicale/config. Custom paths can be specified with the --config /path/to/config command line argument or the RADICALE_CONFIG environment variable. Multiple configuration files can be separated by : (resp. ; on Windows). Paths that start with ? are optional.

The same example configuration via command line arguments looks like:

python3 -m radicale --server-hosts 0.0.0.0:5232,[::]:5232 \
        --auth-type htpasswd --auth-htpasswd-filename ~/.config/radicale/users \
        --auth-htpasswd-encryption autodetect

Add the argument --config "" to stop Radicale from loading the default configuration files. Run python3 -m radicale --help for more information.

You can also use command-line options in startup scripts as shown in the following examples:

## simple variable containing multiple options
RADICALE_OPTIONS="--logging-level=debug --config=/etc/radicale/config --logging-request-header-on-debug --logging-rights-rule-doesnt-match-on-debug"
/usr/bin/radicale $RADICALE_OPTIONS

## variable as array method #1
RADICALE_OPTIONS=("--logging-level=debug" "--config=/etc/radicale/config" "--logging-request-header-on-debug" "--logging-rights-rule-doesnt-match-on-debug")
/usr/bin/radicale ${RADICALE_OPTIONS[@]}

## variable as array method #2
RADICALE_OPTIONS=()
RADICALE_OPTIONS+=("--logging-level=debug")
RADICALE_OPTIONS+=("--config=/etc/radicale/config")
/usr/bin/radicale ${RADICALE_OPTIONS[@]}

The following describes all configuration sections and options.

[server]

The configuration options in this section are only relevant in standalone mode; they are ignored, when Radicale runs on WSGI.

hosts

A comma separated list of addresses that the server will bind to.

Default: localhost:5232

max_connections

The maximum number of parallel connections. Set to 0 to disable the limit.

Default: 8

max_content_length

The maximum size of the request body. (bytes)

Default: 100000000

In case of using a reverse proxy in front of check also there related option

timeout

Socket timeout. (seconds)

Default: 30

ssl

Enable transport layer encryption.

Default: False

certificate

Path of the SSL certificate.

Default: /etc/ssl/radicale.cert.pem

key

Path to the private key for SSL. Only effective if ssl is enabled.

Default: /etc/ssl/radicale.key.pem

certificate_authority

Path to the CA certificate for validating client certificates. This can be used to secure TCP traffic between Radicale and a reverse proxy. If you want to authenticate users with client-side certificates, you also have to write an authentication plugin that extracts the username from the certificate.

Default: (unset)

protocol

(>= 3.3.1)

Accepted SSL protocol (maybe not all supported by underlying OpenSSL version) Example for secure configuration: ALL -SSLv3 -TLSv1 -TLSv1.1 Format: Apache SSLProtocol list (from "mod_ssl")

Default: (system default)

ciphersuite

(>= 3.3.1)

Accepted SSL ciphersuite (maybe not all supported by underlying OpenSSL version) Example for secure configuration: DHE:ECDHE:-NULL:-SHA Format: OpenSSL cipher list (see also "man openssl-ciphers")

Default: (system-default)

script_name

(>= 3.5.0)

Strip script name from URI if called by reverse proxy

Default: (taken from HTTP_X_SCRIPT_NAME or SCRIPT_NAME)

[encoding]

request

Encoding for responding requests.

Default: utf-8

stock

Encoding for storing local collections

Default: utf-8

[auth]

type

The method to verify usernames and passwords.

Available types are:

• none
  Just allows all usernames and passwords.

• denyall (>= 3.2.2)
  Just denies all usernames and passwords.

• htpasswd
  Use an Apache htpasswd file to store usernames and passwords.

• remote_user
  Takes the username from the REMOTE_USER environment variable and disables Radicale's internal HTTP authentication. This can be used to provide the username from a WSGI server which authenticated the client upfront. Requires validation, otherwise clients can supply the header themselves, which then is unconditionally trusted.

• http_x_remote_user
  Takes the username from the X-Remote-User HTTP header and disables Radicale's internal HTTP authentication. This can be used to provide the username from a reverse proxy which authenticated the client upfront. Requires validation, otherwise clients can supply the header themselves, which then is unconditionally trusted.

• ldap (>= 3.3.0)
  Use a LDAP or AD server to authenticate users by relaying credentials from clients and handle results.

• dovecot (>= 3.3.1)
  Use a Dovecot server to authenticate users by relaying credentials from clients and handle results.

• imap (>= 3.4.1)
  Use an IMAP server to authenticate users by relaying credentials from clients and handle results.

• oauth2 (>= 3.5.0)
  Use an OAuth2 server to authenticate users by relaying credentials from clients and handle results. OAuth2 authentication (SSO) directly on client is not supported. Use herefore http_x_remote_user in combination with SSO support in reverse proxy (e.g. Apache+mod_auth_openidc).

• pam (>= 3.5.0)
  Use local PAM to authenticate users by relaying credentials from client and handle result..

Default: none (< 3.5.0) / denyall (>= 3.5.0)

cache_logins

(>= 3.4.0)

Cache successful/failed logins until expiration time. Enable this to avoid overload of authentication backends.

Default: False

cache_successful_logins_expiry

(>= 3.4.0)

Expiration time of caching successful logins in seconds

Default: 15

cache_failed_logins_expiry

(>= 3.4.0)

Expiration time of caching failed logins in seconds

Default: 90

htpasswd_filename

Path to the htpasswd file.

Default: /etc/radicale/users

htpasswd_encryption

The encryption method that is used in the htpasswd file. Use htpasswd or similar to generate this file.

Available methods:

• plain
  Passwords are stored in plaintext. This is not recommended. as it is obviously insecure! The htpasswd file for this can be created by hand and looks like:

  user1:password1
  user2:password2
  

• bcrypt
  This uses a modified version of the Blowfish stream cipher, which is considered very secure. The installation of Python's bcrypt module is required for this to work.

• md5
  Use an iterated MD5 digest of the password with salt (nowadays insecure).

• sha256 (>= 3.1.9)
  Use an iterated SHA-256 digest of the password with salt.

• sha512 (>= 3.1.9)
  Use an iterated SHA-512 digest of the password with salt.

• argon2 (>= 3.5.3)
  Use an iterated ARGON2 digest of the password with salt. The installation of Python's argon2-cffi module is required for this to work.

• autodetect (>= 3.1.9)
  Automatically detect the encryption method used per user entry.

Default: md5 (< 3.3.0) / autodetect (>= 3.3.0)

htpasswd_cache

(>= 3.4.0)

Enable caching of htpasswd file based on size and mtime_ns

Default: False

delay

Average delay (in seconds) after failed login attempts.

Default: 1

realm

Message displayed in the client when a password is needed.

Default: Radicale - Password Required

ldap_uri

(>= 3.3.0)

URI to the LDAP server. Mandatory for auth type ldap.

Default: ldap://localhost

ldap_base

(>= 3.3.0)

Base DN of the LDAP server. Mandatory for auth type ldap.

Default: (unset)

ldap_reader_dn

(>= 3.3.0)

DN of a LDAP user with read access users and - if defined - groups. Mandatory for auth type ldap.

Default: (unset)

ldap_secret

(>= 3.3.0)

Password of ldap_reader_dn. Mandatory for auth type ldap unless ldap_secret_file is given.

Default: (unset)

ldap_secret_file

(>= 3.3.0)

Path to the file containing the password of ldap_reader_dn. Mandatory for auth type ldap unless ldap_secret is given.

Default: (unset)

ldap_filter

(>= 3.3.0)

Filter to search for the LDAP entry of the user to authenticate. It must contain '{0}' as placeholder for the login name.

Default: (cn={0})

ldap_user_attribute

(>= 3.4.0)

LDAP attribute whose value shall be used as the username after successful authentication.

If set, you can use flexible logins in ldap_filter and still have consolidated usernames, e.g. to allow users to login using mail addresses as an alternative to cn, simply set

ldap_filter = (&(objectclass=inetOrgPerson)(|(cn={0})(mail={0})))
ldap_user_attribute = cn

Even for simple filter setups, it is recommended to set it in order to get usernames exactly as they are stored in LDAP and to avoid inconsistencies in the upper-/lower-case spelling of the login names.

Default: (unset, in which case the login name is directly used as the username)

ldap_use_ssl

(>= 3.3.0)

Use ssl on the LDAP connection. Deprecated! Use ldap_security instead.

ldap_security

(>= 3.5.2)

Use encryption on the LDAP connection.

One of

• none
• tls
• starttls

Default: none

ldap_ssl_verify_mode

(>= 3.3.0)

Certificate verification mode for tls and starttls.

One of

• NONE
• OPTIONAL
• REQUIRED.

Default: REQUIRED

ldap_ssl_ca_file

(>= 3.3.0)

Path to the CA file in PEM format which is used to certify the server certificate

Default: (unset)

ldap_groups_attribute

(>= 3.4.0)

LDAP attribute in the authenticated user's LDAP entry to read the group memberships from.

E.g. memberOf to get groups on Active Directory and alikes, groupMembership on Novell eDirectory, ...

If set, get the user's LDAP groups from the attribute given.

For DN-valued attributes, the value of the RDN is used to determine the group names. The implementation also supports non-DN-valued attributes: their values are taken directly.

The user's group names can be used later to define rights. They also give you access to the group calendars, if those exist.

• Group calendars are placed directly under collection_root_folder/GROUPS/ with the base64-encoded group name as the calendar folder name.
• Group calendar folders are not created automatically. This must be done manually. In the LDAP-authentication section of Radicale's wiki you can find a script to create a group calendar.

Default: (unset)

ldap_group_members_attribute

(>= 3.5.6)

Attribute in the group entries to read the group's members from.

E.g. member for groups with objectclass groupOfNames.

Using ldap_group_members_attribute, ldap_group_base and ldap_group_filter is an alternative approach to getting the user's groups. Instead of reading them from ldap_groups_attribute in the user's entry, an additional query is performed to seach for those groups beneath ldap_group_base, that have the user's DN in their ldap_group_members_attribute and additionally fulfil ldap_group_filter.

As with DN-valued ldap_groups_attribute, the value of the RDN is used to determine the group names.

Default: (unset)

ldap_group_base

(>= 3.5.6)

Base DN to search for groups. Only necessary if ldap_group_members_attribute is set, and if the base DN for groups differs from ldap_base.

Default: (unset, in which case ldap_base is used as fallback)

ldap_group_filter

(>= 3.5.6)

Search filter to search for groups having the user DN found as member. Only necessary ldap_group_members_attribute is set, and you want the groups returned to be restricted instead of all groups the user's DN is in.

Default: (unset)

ldap_ignore_attribute_create_modify_timestamp

(>= 3.5.1)

Quirks for Authentik LDAP server, which violates the LDAP RFCs: add modifyTimestamp and createTimestamp to the exclusion list of internal ldap3 client so that these schema attributes are not checked.

Default: False

dovecot_connection_type

(>= 3.4.1)

Connection type for dovecot authentication.

One of:

• AF_UNIX
• AF_INET
• AF_INET6

Note: credentials are transmitted in cleartext

Default: AF_UNIX

dovecot_socket

(>= 3.3.1)

Path to the Dovecot client authentication socket (eg. /run/dovecot/auth-client on Fedora). Radicale must have read & write access to the socket.

Default: /var/run/dovecot/auth-client

dovecot_host

(>= 3.4.1)

Host of dovecot socket exposed via network

Default: localhost

dovecot_port

(>= 3.4.1)

Port of dovecot socket exposed via network

Default: 12345

remote_ip_source

(>= 3.5.6)

For authentication mechanisms that are made aware of the remote IP (such as dovecot via the rip= auth protocol parameter), determine the source to use. Currently, valid values are

REMOTE_ADDR (default)

Use the REMOTE_ADDR environment variable that captures the remote address of the socket connection.

X-Remote-Addr

Use the X-Remote-Addr HTTP header value.

In the case of X-Remote-Addr, Radicale must be running be running behind a proxy that you control and that sets/overwrites the X-Remote-Addr header (doesn't pass it) so that the value passed to dovecot is reliable. For example, for nginx, add

    proxy_set_header  X-Remote-Addr $remote_addr;

to the configuration sample.

Default: REMOTE_ADDR

imap_host

(>= 3.4.1)

IMAP server hostname.

One of:

• address
• address:port
• imap.server.tld

Default: localhost

imap_security

(>= 3.4.1)

Secure the IMAP connection:

One of:

• tls
• starttls
• none

Default: tls

oauth2_token_endpoint

(>= 3.5.0)

Endpoint URL for the OAuth2 token

Default: (unset)

pam_service

(>= 3.5.0)

PAM service name

Default: radicale

pam_group_membership

(>= 3.5.0)

PAM group user should be member of

Default: (unset)

lc_username

Сonvert username to lowercase. Recommended to be True for case-insensitive auth providers like ldap, kerberos, ...

Default: False

Notes:

• lc_username and uc_username are mutually exclusive
• for auth type ldap the use of ldap_user_attribute is preferred over lc_username

uc_username

(>= 3.3.2)

Сonvert username to uppercase. Recommended to be True for case-insensitive auth providers like ldap, kerberos, ...

Default: False

Notes:

• uc_username and lc_username are mutually exclusive
• for auth type ldap the use of ldap_user_attribute is preferred over uc_username

strip_domain

(>= 3.2.3)

Strip domain from username

Default: False

urldecode_username

(>= 3.5.3)

URL-decode the username. If the username is an email address, some clients send the username URL-encoded (notably iOS devices) breaking the authentication process (user@example.com becomes user%40example.com). This setting forces decoding the username.

Default: False

[rights]

type

Authorization backend that is used to check the access rights to collections.

The default and recommended backend is owner_only. If access to calendars and address books outside the user's collection directory (that's /username/) is granted, clients will not detect these collections automatically and will not show them to the users. Choosing any other authorization backend is only useful if you access calendars and address books directly via URL.

Available backends are:

• authenticated
  Authenticated users can read and write everything.

• owner_only
  Authenticated users can read and write their own collections under the path /USERNAME/.

• owner_write
  Authenticated users can read everything and write their own collections under the path /USERNAME/.

• from_file
  Load the rules from a file.

Default: owner_only

file

Name of the file containing the authorization rules for the from_file backend. See the Rights section for details.

Default: /etc/radicale/rights

permit_delete_collection

(>= 3.1.9)

Global permission to delete complete collections.

• If False it can be explicitly granted per collection by permissions: D
• If True it can be explicitly forbidden per collection by permissions: d

Default: True

permit_overwrite_collection

(>= 3.3.0)

Global permission to overwrite complete collections.

• If False it can be explicitly granted per collection by permissions: O
• If True it can be explicitly forbidden per collection by permissions: o

Default: True

[storage]

type

Backend used to store data.

Available backends are:

• multifilesystem
  Stores the data in the filesystem.

• multifilesystem_nolock
  The multifilesystem backend without file-based locking. Must only be used with a single process.

Default: multifilesystem

filesystem_folder

Folder for storing local collections; will be auto-created if not present.

Default: /var/lib/radicale/collections

filesystem_cache_folder

(>= 3.3.2)

Folder for storing cache of local collections; will be auto-created if not present

Default: (filesystem_folder)

Note: only used if use_cache_subfolder_* options are active

Note: can be used on multi-instance setup to cache files on local node (see below)

use_cache_subfolder_for_item

(>= 3.3.2)

Use subfolder collection-cache for cache file structure of 'item' instead of inside collection folders, created if not present

Default: False

Note: can be used on multi-instance setup to cache 'item' on local node

use_cache_subfolder_for_history

(>= 3.3.2)

Use subfolder collection-cache for cache file structure of 'history' instead of inside collection folders, created if not present

Default: False

Note: only use on single-instance setup: it will break consistency with clients in multi-instance setup

use_cache_subfolder_for_synctoken

(>= 3.3.2)

Use subfolder collection-cache for cache file structure of 'sync-token' instead of inside collection folders, created if not present

Default: False

Note: only use on single-instance setup: it will break consistency with clients in multi-instance setup

use_mtime_and_size_for_item_cache

(>= 3.3.2)

Use last modification time (in nanoseconds) and size (in bytes) for 'item' cache instead of SHA256 (improves speed)

Default: False

Notes:

• check used filesystem mtime precision before enabling
• conversion is done on access
• bulk conversion can be done offline using the storage verification option radicale --verify-storage

folder_umask

(>= 3.3.2)

umask to use for folder creation (not applicable for OS Windows)

Default: (system-default, usually 0022)

Useful values:

• 0077 (user:rw group:- other:-)
• 0027 (user:rw group:r other:-)
• 0007 (user:rw group:rw other:-)
• 0022 (user:rw group:r other:r)

max_sync_token_age

Delete sync-tokens that are older than the specified time (in seconds).

Default: 2592000

skip_broken_item

(>= 3.2.2)

Skip broken item instead of triggering an exception

Default: True

hook

Command that is run after changes to storage. See the Versioning collections with Git tutorial for an example.

Default: (unset)

Supported placeholders:

• %(user)s: logged-in user
• %(cwd)s: current working directory (>= 3.5.1)
• %(path)s: full path of item (>= 3.5.1)
• %(to_path)s: full path of destination item (only set on MOVE request) (>= 3.5.5)
• %(request)s: request method (>= 3.5.5)

The command will be executed with base directory defined in filesystem_folder (see above)

predefined_collections

Create predefined user collections.

Example:

{
  "def-addressbook": {
     "D:displayname": "Personal Address Book",
     "tag": "VADDRESSBOOK"
  },
  "def-calendar": {
     "C:supported-calendar-component-set": "VEVENT,VJOURNAL,VTODO",
     "D:displayname": "Personal Calendar",
     "tag": "VCALENDAR"
  }
}

Default: (unset)

[web]

type

The backend that provides the web interface of Radicale.

Available backends are:

• none
  Simply shows the message "Radicale works!".

• internal
  Allows creation and management of address books and calendars.

Default: internal

[logging]

level

Set the logging level.

Available levels are:

• debug
• info
• warning
• error
• critical

Default: warning (< 3.2.0) / info (>= 3.2.0)

trace_on_debug

(> 3.5.4)

Do not filter debug messages starting with 'TRACE'

Default: False

trace_filter

(> 3.5.4)

Filter debug messages starting with 'TRACE/'

Prerequisite: trace_on_debug = True

Default: (empty)

mask_passwords

Do not include passwords in logs.

Default: True

bad_put_request_content

(>= 3.2.1)

Log bad PUT request content (for further diagnostics)

Default: False

backtrace_on_debug

(>= 3.2.2)

Log backtrace on level = debug

Default: False

request_header_on_debug

(>= 3.2.2)

Log request on level = debug

Default: False

request_content_on_debug

(>= 3.2.2)

Log request on level = debug

Default: False

response_content_on_debug

(>= 3.2.2)

Log response on level = debug

Default: False

rights_rule_doesnt_match_on_debug

(>= 3.2.3)

Log rights rule which doesn't match on level = debug

Default: False

storage_cache_actions_on_debug

(>= 3.3.2)

Log storage cache actions on level = debug

Default: False

[headers]

This section can be used to specify additional HTTP headers that will be sent to clients.

An example to relax the same-origin policy:

Access-Control-Allow-Origin = *

[hook]

type

Hook binding for event changes and deletion notifications.

Available types are:

• none
  Disabled. Nothing will be notified.

• rabbitmq (>= 3.2.0)
  Push the message to the rabbitmq server.

• email (>= 3.5.5)
  Send an email notification to event attendees.

Default: none

dryrun

(> 3.5.4)

Dry-Run / simulate (i.e. do not really trigger) the hook action.

Default: False

rabbitmq_endpoint

(>= 3.2.0)

End-point address for rabbitmq server. E.g.: amqp://user:password@localhost:5672/

Default: (unset)

rabbitmq_topic

(>= 3.2.0)

RabbitMQ topic to publish message in.

Default: (unset)

rabbitmq_queue_type

(>= 3.2.0)

RabbitMQ queue type for the topic.

Default: classic

smtp_server

(>= 3.5.5)

Address of SMTP server to connect to.

Default: (unset)

smtp_port

(>= 3.5.5)

Port on SMTP server to connect to.

Default:

smtp_security

(>= 3.5.5)

Use encryption on the SMTP connection.

One of:

• none
• tls
• starttls

Default: none

smtp_ssl_verify_mode

(>= 3.5.5)

The certificate verification mode for tls and starttls.

One of:

• NONE
• OPTIONAL
• REQUIRED

Default: REQUIRED

smtp_username

(>= 3.5.5)

Username to authenticate with SMTP server. Leave empty to disable authentication (e.g. using local mail server).

Default: (unset)

smtp_password

(>= 3.5.5)

Password to authenticate with SMTP server. Leave empty to disable authentication (e.g. using local mail server).

Default: (unset)

from_email

(>= 3.5.5)

Email address to use as sender in email notifications.

Default: (unset)

mass_email

(>= 3.5.5)

When enabled, send one email to all attendee email addresses. When disabled, send one email per attendee email address.

Default: False

new_or_added_to_event_template

(>= 3.5.5)

Template to use for added/updated event email body sent to an attendee when the event is created or they are added to a pre-existing event.

The following placeholders will be replaced:

• $organizer_name: Name of the organizer, or "Unknown Organizer" if not set in event
• $from_email: Email address the email is sent from
• $attendee_name: Name of the attendee (email recipient), or "everyone" if mass email enabled.
• $event_name: Name/summary of the event, or "No Title" if not set in event
• $event_start_time: Start time of the event in ISO 8601 format
• $event_end_time: End time of the event in ISO 8601 format, or "No End Time" if the event has no end time
• $event_location: Location of the event, or "No Location Specified" if not set in event

Providing any words prefixed with $ not included in the list above will result in an error.

Default:

Hello $attendee_name,

You have been added as an attendee to the following calendar event.

    $event_title
    $event_start_time - $event_end_time
    $event_location

This is an automated message. Please do not reply.

deleted_or_removed_from_event_template

(>= 3.5.5)

Template to use for deleted/removed event email body sent to an attendee when the event is deleted or they are removed from the event.

The following placeholders will be replaced:

• $organizer_name: Name of the organizer, or "Unknown Organizer" if not set in event
• $from_email: Email address the email is sent from
• $attendee_name: Name of the attendee (email recipient), or "everyone" if mass email enabled.
• $event_name: Name/summary of the event, or "No Title" if not set in event
• $event_start_time: Start time of the event in ISO 8601 format
• $event_end_time: End time of the event in ISO 8601 format, or "No End Time" if the event has no end time
• $event_location: Location of the event, or "No Location Specified" if not set in event

Providing any words prefixed with $ not included in the list above will result in an error.

Default:

Hello $attendee_name,

The following event has been deleted.

    $event_title
    $event_start_time - $event_end_time
    $event_location

This is an automated message. Please do not reply.

updated_event_template

(>= 3.5.5)

Template to use for updated event email body sent to an attendee when non-attendee-related details of the event are updated.

Existing attendees will NOT be notified of a modified event if the only changes are adding/removing other attendees.

The following placeholders will be replaced:

• $organizer_name: Name of the organizer, or "Unknown Organizer" if not set in event
• $from_email: Email address the email is sent from
• $attendee_name: Name of the attendee (email recipient), or "everyone" if mass email enabled.
• $event_name: Name/summary of the event, or "No Title" if not set in event
• $event_start_time: Start time of the event in ISO 8601 format
• $event_end_time: End time of the event in ISO 8601 format, or "No End Time" if the event has no end time
• $event_location: Location of the event, or "No Location Specified" if not set in event

Providing any words prefixed with $ not included in the list above will result in an error.

Default:

Hello $attendee_name,
            
The following event has been updated.

    $event_title
    $event_start_time - $event_end_time
    $event_location
    
This is an automated message. Please do not reply.

[reporting]

max_freebusy_occurrence

(>= 3.2.3)

When returning a free-busy report, a list of busy time occurrences are generated based on a given time frame. Large time frames could generate a lot of occurrences based on the time frame supplied. This setting limits the lookup to prevent potential denial of service attacks on large time frames. If the limit is reached, an HTTP error is thrown instead of returning the results.

Default: 10000

Supported Clients

Radicale has been tested with:

• Android with DAVx⁵ (formerly DAVdroid),
• OneCalendar
• GNOME Calendar, Contacts and Evolution
• KDE PIM Applications, KDE Merkuro
• Mozilla Thunderbird (Thunderbird/Radicale) with CardBook and Lightning
• InfCloud (InfCloud/Radicale), CalDavZAP, CardDavMATE and Open Calendar
• pimsync (pimsync/Radicale)

Many clients do not support the creation of new calendars and address books. You can use Radicale's web interface (e.g. http://localhost:5232) to create and manage address books and calendars.

In some clients, it is sufficient to simply enter the URL of the Radicale server (e.g. http://localhost:5232) and your username. In others, you have to enter the URL of the collection directly (e.g. http://localhost:5232/user/calendar).

Some clients (notably macOS's Calendar.app) may silently refuse to include account credentials over unsecured HTTP, leading to unexpected authentication failures. In these cases, you want to make sure the Radicale server is accessible over HTTPS.

DAVx⁵

Enter the URL of the Radicale server (e.g. http://localhost:5232) and your username. DAVx⁵ will show all existing calendars and address books and you can create new ones.

OneCalendar

When adding account, select CalDAV account type, then enter username, password and the Radicale server (e.g. https://yourdomain:5232). OneCalendar will show all existing calendars and (FIXME: address books), you need to select which ones you want to see. OneCalendar supports many other server types too.

GNOME Calendar, Contacts

GNOME 46 added CalDAV and CardDAV support to GNOME Online Accounts.

Open GNOME Settings, navigate to Online Accounts > Connect an Account > Calendar, Contacts and Files. Enter the URL (e.g. https://example.com/radicale) and your credentials then click Sign In. In the pop-up dialog, turn off Files. After adding Radicale in GNOME Online Accounts, it should be available in GNOME Contacts and GNOME Calendar.

Evolution

In Evolution add a new calendar and address book respectively with WebDAV. Enter the URL of the Radicale server (e.g. http://localhost:5232) and your username. Clicking on the search button will list the existing calendars and address books.

Adding CalDAV and CardDAV accounts in Evolution will automatically make them available in GNOME Contacts and GNOME Calendar.

KDE PIM Applications

In Kontact add a DAV Groupware resource to Akonadi under Settings > Configure Kontact > Calendar > General > Calendars, select the protocol (CalDAV or CardDAV), add the URL to the Radicale collections and enter the credentials. After synchronization of the calendar resp. addressbook items, you can manage them in Kontact.

Thunderbird

Add a new calendar on the network. Enter your username and the URL of the Radicale server (e.g. http://localhost:5232). After asking for your password, it will list the existing calendars.

Adress books with CardBook add-on

Add a new address book on the network with CardDAV. Enter the URL of the Radicale server (e.g. http://localhost:5232) and your username and password. It will list your existing address books.

InfCloud, CalDavZAP and CardDavMATE

You can integrate InfCloud into Radicale's web interface with by simply downloading the latest package from InfCloud and extract the content into a folder named infcloud in radicale/web/internal_data/.

No further adjustments are required as content is adjusted on the fly (tested with 0.13.1).

See also Wiki/Client InfCloud.

Command line

This is not the recommended way of creating and managing your calendars and address books. Use Radicale's web interface or a client with support for it (e.g. DAVx⁵).

To create a new calendar run something like:

$ curl -u user -X MKCOL 'http://localhost:5232/user/calendar' --data \
'<?xml version="1.0" encoding="UTF-8" ?>
<create xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:I="http://apple.com/ns/ical/">
  <set>
    <prop>
      <resourcetype>
        <collection />
        <C:calendar />
      </resourcetype>
      <C:supported-calendar-component-set>
        <C:comp name="VEVENT" />
        <C:comp name="VJOURNAL" />
        <C:comp name="VTODO" />
      </C:supported-calendar-component-set>
      <displayname>Calendar</displayname>
      <C:calendar-description>Example calendar</C:calendar-description>
      <I:calendar-color>#ff0000ff</I:calendar-color>
    </prop>
  </set>
</create>'

To create a new address book run something like:

$ curl -u user -X MKCOL 'http://localhost:5232/user/addressbook' --data \
'<?xml version="1.0" encoding="UTF-8" ?>
<create xmlns="DAV:" xmlns:CR="urn:ietf:params:xml:ns:carddav">
  <set>
    <prop>
      <resourcetype>
        <collection />
        <CR:addressbook />
      </resourcetype>
      <displayname>Address book</displayname>
      <CR:addressbook-description>Example address book</CR:addressbook-description>
    </prop>
  </set>
</create>'

The collection /USERNAME will be created automatically, when the user authenticates to Radicale for the first time. Clients with automatic discovery of collections will only show calendars and address books that are direct children of the path /USERNAME/.

Delete the collections by running something like:

curl -u user -X DELETE 'http://localhost:5232/user/calendar'

Note: requires config/option permit_delete_collection = True

Authorization and Rights

This section describes the format of the rights file for the from_file authentication backend. The configuration option file in the rights section must point to the rights file.

The recommended rights method is owner_only. If access is granted to calendars and address books outside the home directory of users (that's /USERNAME/), clients will not detect these collections automatically, and will not show them to the users. This is only useful if you access calendars and address books directly via URL.

An example rights file:

# Allow reading root collection for authenticated users
[root]
user: .+
collection:
permissions: R

# Allow reading and writing principal collection (same as username)
[principal]
user: .+
collection: {user}
permissions: RW

# Allow reading and writing calendars and address books that are direct
# children of the principal collection
[calendars]
user: .+
collection: {user}/[^/]+
permissions: rw

The titles of the sections are ignored (but must be unique). The keys user and collection contain regular expressions, that are matched against the username and the path of the collection. Permissions from the first matching section are used. If no section matches, access gets denied.

The username is empty for anonymous users. Therefore, the regex .+ only matches authenticated users and .* matches everyone (including anonymous users).

The path of the collection is separated by / and has no leading or trailing /. Therefore, the path of the root collection is empty.

In the collection regex you can use {user} and get groups from the user regex with {0}, {1}, etc.

In consequence of the parameter substitution you have to write {{ and }} if you want to use regular curly braces in the user and collection regexes.

The following permissions are recognized:

• R: read collections (excluding address books and calendars)
• r: read address book and calendar collections
• i: subset of r that only allows direct access via HTTP method GET (CalDAV/CardDAV is susceptible to expensive search requests)
• W: write collections (excluding address books and calendars)
• w: write address book and calendar collections
• D: allow deleting a collection in case permit_delete_collection=False (>= 3.3.0)
• d: deny deleting a collection in case permit_delete_collection=True (>= 3.3.0)
• O: allow overwriting a collection in case permit_overwrite_collection=False
• o: deny overwriting a collection in case permit_overwrite_collection=True

Storage

This document describes the layout and format of the file system storage, the multifilesystem backend.

It is safe to access and manipulate the data by hand or with scripts. Scripts can be invoked manually, periodically (e.g. using cron) or after each change to the storage with the configuration option hook in the storage section (e.g. Versioning collections with Git).

Layout

The file system comprises the following files and folders:

• .Radicale.lock: The lock file for locking the storage.
• collection-root: This folder contains all collections and items.

Each collection is represented by a folder. This folder may contain the file .Radicale.props with all WebDAV properties of the collection encoded as JSON.

Each item in a calendar or address book collection is represented by a file containing the item's iCalendar resp. vCard data.

All files and folders, whose names start with a dot but not with .Radicale. (internal files) are ignored.

Syntax errors in any of the files will cause all requests accessing the faulty data to fail. The logging output should contain the names of the culprits.

Caches and sync-tokens are stored in the .Radicale.cache folder inside of collections. This folder may be created or modified, while the storage is locked for shared access. In theory, it should be safe to delete the folder. Caches will be recreated automatically and clients will be told that their sync-token is not valid anymore.

You may encounter files or folders that start with .Radicale.tmp-. Radicale uses them for atomic creation and deletion of files and folders. They should be deleted after requests are finished but it is possible that they are left behind when Radicale or the computer crashes. You can safely delete them.

Locking

When the data is accessed by hand or by an externally invoked script, the storage must be locked. The storage can be locked for exclusive or shared access. It prevents Radicale from reading or writing the file system. The storage is locked with exclusive access while the hook runs.

Linux shell scripts

Use the flock utility to acquire exclusive or shared locks for the commands you want to run on Radicale's data.

# Exclusive lock for COMMAND
$ flock --exclusive /path/to/storage/.Radicale.lock COMMAND
# Shared lock for COMMAND
$ flock --shared /path/to/storage/.Radicale.lock COMMAND

Linux and MacOS

Use the flock syscall. Python provides it in the fcntl module.

Windows

Use LockFile for exclusive access or LockFileEx which also supports shared access. Setting nNumberOfBytesToLockLow to 1 and nNumberOfBytesToLockHigh to 0 works.

Manually creating collections

To create a new collection, you need to create the corresponding folder in the file system storage (e.g. collection-root/user/calendar). To indicate to Radicale and clients that the collection is a calendar, you have to create the file .Radicale.props with the following content in the folder:

{"tag": "VCALENDAR"}

The calendar is now available at the URL path (e.g. /user/calendar). For address books .Radicale.props must contain:

{"tag": "VADDRESSBOOK"}

Calendar and address book collections must not have any child collections. Clients with automatic discovery of collections will only show calendars and address books that are direct children of the path /USERNAME/.

Delete collections by deleting the corresponding folders.

Logging overview

Radicale logs to stderr. The verbosity of the log output can be controlled with --debug command line argument or the level configuration option in the logging section.

Architecture

Radicale is a small piece of software, but understanding it is not as easy as it seems. But don't worry, reading this short section is enough to understand what a CalDAV/CardDAV server is, and how Radicale's code is organized.

Protocol overview

Here is a simple overview of the global architecture for reaching a calendar or an address book through network:

Part	Layer	Protocol or Format
Server	Calendar/Contact Storage	iCal/vCard
''	Calendar/Contact Server	CalDAV/CardDAV Server
Transfer	Network	CalDAV/CardDAV (HTTP + TLS)
Client	Calendar/Contact Client	CalDAV/CardDAV Client
''	GUI	Terminal, GTK, Web interface, etc.

Radicale is only the server part of this architecture.

Please note:

• CalDAV and CardDAV are extension protocols of WebDAV,
• WebDAV is an extension of the HTTP protocol.

Radicale being a CalDAV/CardDAV server, can also be seen as a special WebDAV and HTTP server.

Radicale is not the client part of this architecture. It means that Radicale never draws calendars, address books, events and contacts on the screen. It only stores them and give the possibility to share them online with other people.

If you want to see or edit your events and your contacts, you have to use another software called a client, that can be a "normal" applications with icons and buttons, a terminal or another web application.

Code Architecture

The radicale package offers the following modules.

• __init__

  Contains the entry point for WSGI.

• __main__

  Provides the entry point for the radicale executable and includes the command line parser. It loads configuration files from the default (or specified) paths and starts the internal server.

• app

  This is the core part of Radicale, with the code for the CalDAV/CardDAV server. The code managing the different HTTP requests according to the CalDAV/CardDAV specification can be found here.

• auth

  Used for authenticating users based on username and password, mapping usernames to internal users and optionally retrieving credentials from the environment.

• config

  Contains the code for managing configuration and loading settings from files.

• ìtem

  Internal representation of address book and calendar entries. Based on VObject.

• log

  The logger for Radicale based on the default Python logging module.

• rights

  This module is used by Radicale to manage access rights to collections, address books and calendars.

• server : The integrated HTTP server for standalone use.

• storage

  This module contains the classes representing collections in Radicale and the code for storing and loading them in the filesystem.

• web

  This module contains the web interface.

• utils

  Contains general helper functions.

• httputils

  Contains helper functions for working with HTTP.

• pathutils

  Helper functions for working with paths and the filesystem.

• xmlutils

  Helper functions for working with the XML part of CalDAV/CardDAV requests and responses. It's based on the ElementTree XML API.

Plugins

Radicale can be extended by plugins for authentication, rights management and storage. Plugins are python modules.

Getting started with plugin development

To get started we walk through the creation of a simple authentication plugin, that accepts login attempts with a static password.

The easiest way to develop and install python modules is Distutils. For a minimal setup create the file setup.py with the following content in an empty folder:

#!/usr/bin/env python3

from distutils.core import setup

setup(name="radicale_static_password_auth",
      packages=["radicale_static_password_auth"])

In the same folder create the sub-folder radicale_static_password_auth. The folder must have the same name as specified in packages above.

Create the file __init__.py in the radicale_static_password_auth folder with the following content:

from radicale.auth import BaseAuth
from radicale.log import logger

PLUGIN_CONFIG_SCHEMA = {"auth": {
    "password": {"value": "", "type": str}}}


class Auth(BaseAuth):
    def __init__(self, configuration):
        super().__init__(configuration.copy(PLUGIN_CONFIG_SCHEMA))

    def _login(self, login, password):
        # Get password from configuration option
        static_password = self.configuration.get("auth", "password")
        # Check authentication
        logger.info("Login attempt by %r with password %r",
                    login, password)
        if password == static_password:
            return login
        return ""

Install the python module by running the following command in the same folder as setup.py:

python3 -m pip install .

To make use this great creation in Radicale, set the configuration option type in the auth section to radicale_static_password_auth:

[auth]
type = radicale_static_password_auth
password = secret

You can uninstall the module with:

python3 -m pip uninstall radicale_static_password_auth

Authentication plugins

This plugin type is used to check login credentials. The module must contain a class Auth that extends radicale.auth.BaseAuth. Take a look at the file radicale/auth/__init__.py in Radicale's source code for more information.

Rights management plugins

This plugin type is used to check if a user has access to a path. The module must contain a class Rights that extends radicale.rights.BaseRights. Take a look at the file radicale/rights/__init__.py in Radicale's source code for more information.

Web plugins

This plugin type is used to provide the web interface for Radicale. The module must contain a class Web that extends radicale.web.BaseWeb. Take a look at the file radicale/web/__init__.py in Radicale's source code for more information.

Storage plugins

This plugin is used to store collections and items. The module must contain a class Storage that extends radicale.storage.BaseStorage. Take a look at the file radicale/storage/__init__.py in Radicale's source code for more information.

Contribute

Report Bugs

Found a bug? Want a new feature? Report a new issue on the Radicale bug-tracker.

Hack

Interested in hacking? Feel free to clone the git repository on GitHub if you want to add new features, fix bugs or update the documentation.

Documentation

To change or complement the documentation create a pull request to DOCUMENTATION.md.

Download

PyPI

Radicale is available on PyPI. To install, just type as superuser:

python3 -m pip install --upgrade radicale

Git Repository

If you want the development version of Radicale, take a look at the git repository on GitHub, or install it directly with:

python3 -m pip install --upgrade https://github.com/Kozea/Radicale/archive/master.tar.gz

You can also download the content of the repository as an archive.

Source Packages

You can find the source packages of all releases on GitHub.

Docker

Radicale is available as a Docker image for platforms linux/amd64 and linux/arm64. To install the latest version, run:

docker pull ghcr.io/kozea/radicale:latest

An example docker-compose.yml and detailed instructions will soon be updated.

Linux Distribution Packages

Radicale has been packaged for:

• ArchLinux by David Runge
• Debian by Jonas Smedegaard
• Gentoo by René Neumann, Maxim Koltsov and Manuel Rüger
• Fedora/EnterpriseLinux by Jorti and Peter Bieringer
• Mageia by Jani Välimaa
• OpenBSD by Sergey Bronnikov, Stuart Henderson and Ian Darwin
• openSUSE by Ákos Szőts and Rueckert
• PyPM
• Slackware by Johannes Schöpfer
• Trisquel
• Ubuntu by the MOTU and Jonas Smedegaard

Radicale is also available on Cloudron.

If you are interested in creating packages for other Linux distributions, read the "Contribute" section.

About

Main Goals

Radicale is a complete calendar and contact storing and manipulating solution. It can store multiple calendars and multiple address books.

Calendar and contact manipulation is available from both local and distant accesses, possibly limited through authentication policies.

It aims to be a lightweight solution, easy to use, easy to install, easy to configure. As a consequence, it requires few software dependencies and is preconfigured to work out-of-the-box.

Radicale is written in Python. It runs on most of the UNIX-like platforms (Linux, *BSD, macOS) and Windows. It is free and open-source software.

What Radicale Will Never Be

Radicale is a server, not a client. No interfaces will be created to work with the server.

CalDAV and CardDAV are not perfect protocols. We think that their main problem is their complexity, that is why we decided not to implement the whole standard but just enough to understand some of its client-side implementations.

CalDAV and CardDAV are the best open standards available, and they are quite widely used by both clients and servers. We decided to use it, and we will not use another one.

Technical Choices

Important global development choices have been decided before writing code. They are very useful to understand why the Radicale Project is different from other CalDAV and CardDAV servers, and why features are included or not in the code.

Oriented to Calendar and Contact User Agents

Calendar and contact servers work with calendar and contact clients, using a defined protocol. CalDAV and CardDAV are good protocols, covering lots of features and use cases, but it is quite hard to implement fully.

Some calendar servers have been created to follow the CalDAV and CardDAV RFCs as much as possible: Davical, Baïkal and Darwin Calendar Server, for example, are much more respectful of CalDAV and CardDAV and can be used with many clients. They are very good choices if you want to develop and test new CalDAV clients, or if you have a possibly heterogeneous list of user agents.

Even if it tries it best to follow the RFCs, Radicale does not and will not blindly implement the CalDAV and CardDAV standards. It is mainly designed to support the CalDAV and CardDAV implementations of different clients.

Simple

Radicale is designed to be simple to install, simple to configure, simple to use.

The installation is very easy, particularly with Linux: one dependency, no superuser rights needed, no configuration required, no database. Installing and launching the main script out-of-the-box, as a normal user, are often the only steps to have a simple remote calendar and contact access.

Contrary to other servers that are often complicated, require high privileges or need a strong configuration, the Radicale Server can (sometimes, if not often) be launched in a couple of minutes, if you follow the tutorial.

Lazy

The CalDAV RFC defines what must be done, what can be done and what cannot be done. Many violations of the protocol are totally defined and behaviors are given in such cases.

Radicale often assumes that the clients are perfect and that protocol violations do not exist. That is why most of the errors in client requests have undetermined consequences for the lazy server that can reply good answers, bad answers, or even no answer.

History

Radicale has been started as a (free topic) stupid school project replacing another (assigned topic) even more stupid school project.

At the beginning, it was just a proof-of-concept. The main goal was to write a small, dirty and simple CalDAV server working with Lightning, using no external libraries. That's how we created a piece of code that's (quite) easy to understand, to use and to hack.

The first lines have been added to the SVN (!) repository as I was drinking (many) beers at the very end of 2008 (Python 2.6 and 3.0 were just released). It's now packaged for a growing number of Linux distributions.

And that was fun going from here to there thanks to you!