event-remover

Transform your AGH timetable iCal feed by removing events that match a filter (by default: lectures and placeholder blocks).

This is a tiny HTTP service that:

• Serves a simple UI (ui.html) to build a transformed link.
• Fetches your original iCal (.ics) from https://plan.agh.edu.pl/....
• Filters events according to an expression (default: NOT "Wykład" AND NOT "Blokada").
• Returns a valid RFC5545 iCal with matching events removed.

How it works

• run.py exposes endpoints using Python's http.server.
  • GET / serves the UI (from ui.html).
  • GET /transformed?path=<url-encoded-ics-url>[&q=<expr>] fetches the original ICS, filters it, and returns transformed ICS.
  • GET /healthz returns OK for readiness checks.
• matching.py implements a small expression parser and evaluator used for event matching.
• Events are parsed as text blocks between BEGIN:VEVENT and END:VEVENT and tested with the predicate.

UI usage (/)

• Paste your original AGH iCal URL (must start with https://plan.agh.edu.pl/).
• Optionally provide a filter expression (see below). Default is NOT "Wykład" AND NOT "Blokada".
• Click "Transform" to get a new link pointing to /transformed?... on this service.

You can then import the transformed link into your calendar app.

API

GET /transformed

Parameters:

• path (required): URL-encoded original ICS URL (must start with https://plan.agh.edu.pl).
• q (optional): filter expression. Defaults to NOT "Wykład" AND NOT "Blokada".

Responses:

• 200 OK with transformed ICS
• 400 Bad Request if the URL is invalid (wrong origin) or the filter expression is invalid.
• 500 Internal Server Error for unexpected failures.

Filtering syntax

The q parameter is parsed by a simple recursive-descent parser supporting:

• Quoted literals: "some phrase" (double quotes, \" escapes supported inside quotes)
• Operators: NOT, AND, OR
• Parentheses: ( ... )

Precedence:

1. NOT
2. AND
3. OR

Semantics:

• A literal matches if the quoted text is a substring of the raw text of a VEVENT block.
• Operators combine sub-expressions in the obvious way.

Examples:

• Exclude lectures and placeholder blocks (default):
  • NOT "Wykład" AND NOT "Blokada"
• Keep only labs:
  • "Laboratorium"
• Exclude labs or exams:
  • NOT ("Laboratorium" OR "Egzamin")
• Exclude placeholder blocks and lectures except for "Image Processing" Lectures
  • (NOT "Wykład" or "Image Processing") AND NOT "Blokada"

Requirements

• Python 3.8+ (standard library only; no external dependencies)
• Environment variables:
  • PORT – TCP port to listen on (e.g., 8080).
  • ORIGIN – Base URL used by the UI to construct links (e.g., http://localhost:8080).

Quick start

export PORT=8080
export ORIGIN="http://localhost:8080"
python3 run.py
# Open http://localhost:8080 in your browser

Logs & troubleshooting

• Logs are written to ./log.log and to console with timestamps and a per-request trace id.
• If /transformed returns 400 with a trace id, check the server logs for the parsing/validation error.
• Ensure your path really starts with https://plan.agh.edu.pl (hard check in the server).

Deployment

There is a helper script deploy.sh for remote deploys via SSH.

Required environment on the local machine before running deploy.sh:

• REMOTE_USERNAME, REMOTE_HOST, REMOTE_PORT – SSH target.
• PORT, ORIGIN – forwarded to the remote process environment.

What it does:

1. Kills the previous process (pkill -f 'EVENT_REMOVER').
2. Clones/updates the repo.
3. Starts python3 run.py under nohup with PORT and ORIGIN set.
4. Waits for /healthz to return OK.

License

MIT. See LICENSE.