Calendar Bridge

A Nextcloud app that allows administrators to subscribe to external iCal/WebCal feeds and mirror them internally as relay calendars. These calendars are automatically shared read-only with Nextcloud groups, eliminating the need for individual users to subscribe to the feeds themselves.

Project Status

Calendar Bridge is currently under active development and can be tested as an alpha release. It is not yet available in the official Nextcloud App Store. Publishing to the official Nextcloud App Store is the target.

Contributions, optimizations, and feedback are highly welcome!

Features

• Centralized Management: Subscribe to external iCal/WebCal feeds once and mirror them internally.
• Automated Sync: Background synchronization via Nextcloud cron.
• Group Sharing: Automatic read-only sharing with any Nextcloud groups.
• Efficient: Diff-based sync and ETag/Last-Modified support prevent redundant downloads.
• Privacy: Optional stripping of ATTENDEE/ORGANIZER email addresses before storage.
• Security: Support for HTTP Basic Auth and strict SSRF protections.

Requirements

• Nextcloud 30 – 32
• PHP 8.1+
• Reliable Nextcloud cron (systemd timer or crontab recommended)
• DAV app enabled

Installation

Nextcloud App Store

Once published: Apps → Organization → Calendar Bridge → Enable.

Manual Installation

cd /var/www/nextcloud/apps
git clone https://github.com/joe7ean/calendarbridge.git calendarbridge
cd calendarbridge
composer install --no-dev
npm ci && npm run build

Then enable the app in the Nextcloud interface.

Setup

1. Create a Service User

The app requires a dedicated Nextcloud user to own the relay calendars. This account should not be used for regular logins.

# Create the user
php occ user:add --display-name="Calendar Bridge Service" calbridge-service

# Secure the login (set a random password)
RNDPW=$(openssl rand -base64 48)
OC_PASS="$RNDPW" php occ user:resetpassword --password-from-env calbridge-service
unset RNDPW OC_PASS

2. Configure the App

Go to Settings → Administration → Calendar Bridge:

• Default service user: Enter the newly created user (e.g., calbridge-service).
• Adjust other global settings like the sync interval as needed.

3. Add a Feed

In the admin panel under Add feed:

• Enter the URL (https://... or webcal://...).
• Set the name, color, and target groups.

Screenshot

The Calendar Bridge Admin Panel UI:

Development

Requirements: Node.js 20+, PHP 8.1+, Composer.

git clone https://github.com/joe7ean/calendarbridge.git
cd calendarbridge
composer install
npm ci
npm run build

License

AGPL-3.0-only