📅 ICS Calendar Common Slot Finder

A Streamlit-based web application that analyzes multiple .ics calendar files and identifies common free time slots across all participants.

🚀 Features

• Upload up to 10 .ics calendar files

• Automatically detects the overlapping date range across all calendars

• Supports recurring events (e.g. weekly meetings)

• Filters out:

  • Transparent events (TRANSPARENT)
  • Cancelled events (CANCELLED)

• Configurable minimum meeting duration:

  • 30 minutes to 3 hours

• Calculates common free time slots within working hours (08:00–17:00)

• Outputs results as:

  • Interactive table
  • Downloadable CSV file

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🧠 How It Works

1. Each uploaded calendar is parsed and expanded (including recurring events).
2. The app determines the intersection of all calendar date ranges.
3. Busy time intervals are extracted and merged.
4. Free time windows are computed for each day.
5. Only time slots that satisfy the minimum duration requirement are returned.

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📊 Example Use Case

You have multiple team members' calendars and want to find a meeting slot:

• Person A: Jan–Jun
• Person B: May–Sep

👉 The app automatically evaluates only the overlapping period (May–Jun) and finds all possible meeting slots.

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🛠️ Installation

Clone the repository:

git clone https://github.com/EliValLoc/appointment_finder.git
cd appointment_finder

Install dependencies:

pip install -r requirements.txt

Or manually:

pip install streamlit pandas icalendar recurring-ical-events

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▶️ Usage

Run the Streamlit app:

python -m streamlit run streamlit_calender_finder.py

Then open the app in your browser and:

1. Upload your .ics files
2. Select desired meeting duration
3. Choose date range (auto-limited to overlap)
4. Click "Freie Zeitslots berechnen"

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⚙️ Configuration

• Default timezone: Europe/Zurich
• Working hours: 08:00 – 17:00
• Weekends are excluded

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📦 Tech Stack

• Streamlit
• pandas
• icalendar
• recurring-ical-events

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⚠️ Notes

• All processing happens locally in the app session
• No calendar data is stored or transmitted externally
• Accuracy depends on the correctness of the .ics files

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💡 Future Improvements

• Generate all possible start times within free windows
• Support for custom working hours
• Timezone auto-detection per calendar
• UI improvements for large datasets

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🙌 Acknowledgements

Built with the help of OpenAI's GPT models.