OpenWebCalendar

Programs and Python libraries for reading and writing calendars based on the iCalendar standard

Try the service in a VM

Install Nix
Arch Linux
Bash
$ pacman --sync --refresh --noconfirm curl git jq nix
Debian
Bash
$ apt install --yes curl git jq nix
Ubuntu
Bash
$ apt install --yes curl git jq nix

Download a configuration file

# default.nix
{
  ngipkgs ? import (fetchTarball "https://github.com/ngi-nix/ngipkgs/tarball/main") { },
}:
ngipkgs.demo-vm (
  # https://github.com/NixOS/nixpkgs/blob/f34483be5ee2418a563545a56743b7b59c549935/nixos/tests/web-apps/open-web-calendar.nix
  { lib, ... }:

  let
    # required by module, not used
    serverDomain = "open-web-calendar.example.com";
    servicePort = 8080;
  in
  {
    services.open-web-calendar = {
      enable = true;
      domain = serverDomain;
      calendarSettings.title = "My custom title";
    };

    services.nginx = {
      defaultHTTPListenPort = servicePort;
      virtualHosts."${serverDomain}" = {
        forceSSL = lib.mkForce false;
        enableACME = lib.mkForce false;
      };
    };

    networking.hosts."::1" = [ "${serverDomain}" ];
    networking.firewall.allowedTCPPorts = [ servicePort ];
  }

)

    Download

    
  

Enable binary substituters
Bash
```
$ export NIX_CONFIG='substituters = https://cache.nixos.org/ https://ngi.cachix.org/
trusted-public-keys = cache.nixos.org-1:6nchdd59x431o0gwypbmraurkbj16zpmqfgspcdshjy= ngi.cachix.org-1:n+cal72roc3qqulxihpv+tw5t42whxmmhpragkrsrow='
```
Build and run a virtual machine
Arch Linux, Debian Sid and Ubuntu 25.04
Bash
$ nix-build ./default.nix && ./result
Debian 12 and Ubuntu 24.04/24.10
Bash
$ rev=$(nix-instantiate --eval --attr sources.nixpkgs.rev https://github.com/ngi-nix/ngipkgs/archive/master.tar.gz | jq --raw-output)

$ nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/$rev.tar.gz --packages nix --run "nix-build ./default.nix && ./result"
Usage Instructions
Deployment for demo purposes

Options

services.open-web-calendar

services.open-web-calendar.calendarSettings

Configure the default calendar.

See the documentation options in https://open-web-calendar.quelltext.eu/host/configure/#configuring-the-default-calendar and https://github.com/niccokunzmann/open-web-calendar/blob/master/open_web_calendar/default_specification.yml.

Individual calendar instances can be further configured outside this module, by specifying the specification_url parameter.

Type:: JSON value
Default:: { }

services.open-web-calendar.domain

The domain under which open-web-calendar is made available

Type:: string

services.open-web-calendar.enable

Whether to enable OpenWebCalendar service.

Type:: boolean
Default:: false

services.open-web-calendar.package

The open-web-calendar package to use.

Type:: package
Default:: pkgs.open-web-calendar

services.open-web-calendar.settings

Configuration for the server. These are set as environment variables to the gunicorn/flask service.

See the documentation options in https://open-web-calendar.quelltext.eu/host/configure/#configuring-the-server.

Type:: attribute set of (atom (null, bool, int, float or string))
Default:: { }

services.open-web-calendar.settings.ALLOWED_HOSTS Read-only

The hosts that the Open Web Calendar permits. This is required to mitigate the Host Header Injection vulnerability.

We always set this to the empty list, as Nginx already checks the Host header.

Type:: string
Default:: ""

Examples

Enable Open Web Calendar

# https://github.com/NixOS/nixpkgs/blob/f34483be5ee2418a563545a56743b7b59c549935/nixos/tests/web-apps/open-web-calendar.nix
{ lib, ... }:

let
  # required by module, not used
  serverDomain = "open-web-calendar.example.com";
  servicePort = 8080;
in
{
  services.open-web-calendar = {
    enable = true;
    domain = serverDomain;
    calendarSettings.title = "My custom title";
  };

  services.nginx = {
    defaultHTTPListenPort = servicePort;
    virtualHosts."${serverDomain}" = {
      forceSSL = lib.mkForce false;
      enableACME = lib.mkForce false;
    };
  };

  networking.hosts."::1" = [ "${serverDomain}" ];
  networking.firewall.allowedTCPPorts = [ servicePort ];
}

    
    
  

This project is funded by NLnet through these subgrants: