Serve conferences in iCalendar format.

web_view.py

@@ -3,6 +3,7 @@
 """Web page to show upcoming events."""
 
 import decimal
+import hashlib
 import inspect
 import json
 import operator
@@ -11,7 +12,7 @@ import sys
 import time
 import traceback
 from collections import defaultdict
-from datetime import date, datetime, timedelta
+from datetime import date, datetime, timedelta, timezone
 
 import flask
 import UniAuth.auth
@@ -29,7 +30,7 @@ import agenda.thespacedevs
 import agenda.trip
 import agenda.trip_schengen
 import agenda.utils
-from agenda import calendar, format_list_with_ampersand, travel, uk_tz
+from agenda import ical, calendar, format_list_with_ampersand, travel, uk_tz
 from agenda.types import StrDict, Trip
 
 app = flask.Flask(__name__)
@@ -327,6 +328,86 @@ def build_conference_list() -> list[StrDict]:
     return items
 
 
+def _conference_uid(conf: StrDict) -> str:
+    """Generate deterministic UID for conference events."""
+    start = agenda.utils.as_date(conf["start"])
+    raw = f"conference|{start.isoformat()}|{conf.get('name','unknown')}"
+    digest = hashlib.sha1(raw.encode("utf-8")).hexdigest()
+    return f"conference-{digest}@agenda-codex"
+
+
+def _conference_location(conf: StrDict) -> str | None:
+    """Build conference location string."""
+    parts: list[str] = []
+    venue = conf.get("venue")
+    location = conf.get("location")
+    if isinstance(venue, str) and venue.strip():
+        parts.append(venue.strip())
+    if isinstance(location, str) and location.strip():
+        parts.append(location.strip())
+    if country_code := conf.get("country"):
+        country = agenda.get_country(country_code)
+        if country:
+            parts.append(country.name)
+    return ", ".join(parts) if parts else None
+
+
+def _conference_description(conf: StrDict) -> str:
+    """Build textual description for conferences."""
+    lines: list[str] = []
+    if topic := conf.get("topic"):
+        lines.append(f"Topic: {topic}")
+    if venue := conf.get("venue"):
+        lines.append(f"Venue: {venue}")
+    if address := conf.get("address"):
+        lines.append(f"Address: {address}")
+    if url := conf.get("url"):
+        lines.append(f"URL: {url}")
+    status_bits: list[str] = []
+    if conf.get("going"):
+        status_bits.append("attending")
+    if conf.get("speaking"):
+        status_bits.append("speaking")
+    if status_bits:
+        lines.append(f"Status: {', '.join(status_bits)}")
+    return "\n".join(lines) if lines else "Conference"
+
+
+def build_conference_ical(items: list[StrDict]) -> bytes:
+    """Build iCalendar feed for all conferences."""
+    lines = [
+        "BEGIN:VCALENDAR",
+        "VERSION:2.0",
+        "PRODID:-//Agenda Codex//Conferences//EN",
+        "CALSCALE:GREGORIAN",
+        "METHOD:PUBLISH",
+        "X-WR-CALNAME:Conferences",
+    ]
+    generated = datetime.now(tz=timezone.utc)
+
+    for conf in items:
+        start_date = agenda.utils.as_date(conf["start"])
+        end_date = agenda.utils.as_date(conf["end"])
+        end_exclusive = end_date + timedelta(days=1)
+
+        lines.append("BEGIN:VEVENT")
+        ical.append_property(lines, "UID", _conference_uid(conf))
+        ical.append_property(lines, "DTSTAMP", ical.format_datetime_utc(generated))
+        ical.append_property(lines, "DTSTART;VALUE=DATE", ical.format_date(start_date))
+        ical.append_property(lines, "DTEND;VALUE=DATE", ical.format_date(end_exclusive))
+        summary = ical.escape_text(f"conference: {conf['name']}")
+        ical.append_property(lines, "SUMMARY", summary)
+        description = ical.escape_text(_conference_description(conf))
+        ical.append_property(lines, "DESCRIPTION", description)
+        if location := _conference_location(conf):
+            ical.append_property(lines, "LOCATION", ical.escape_text(location))
+        lines.append("END:VEVENT")
+
+    lines.append("END:VCALENDAR")
+    ical_text = "\r\n".join(lines) + "\r\n"
+    return ical_text.encode("utf-8")
+
+
 @app.route("/conference")
 def conference_list() -> str:
     """Page showing a list of conferences."""
@@ -363,6 +444,16 @@ def past_conference_list() -> str:
     )
 
 
+@app.route("/conference/ical")
+def conference_ical() -> werkzeug.Response:
+    """Return all conferences as an iCalendar feed."""
+    items = build_conference_list()
+    ical_data = build_conference_ical(items)
+    response = flask.Response(ical_data, mimetype="text/calendar")
+    response.headers["Content-Disposition"] = "inline; filename=conferences.ics"
+    return response
+
+
 @app.route("/accommodation")
 def accommodation_list() -> str:
     """Page showing a list of past, present and future accommodation."""