feat: add personal ics feeds for assigned tasks

app/models.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import secrets
 from datetime import UTC, date, datetime, timedelta
 
 from flask_login import UserMixin
@@ -24,6 +25,7 @@ class User(UserMixin, TimestampMixin, db.Model):
     password_hash = db.Column(db.String(255), nullable=False)
     is_admin = db.Column(db.Boolean, nullable=False, default=False)
     avatar_path = db.Column(db.String(255), nullable=True)
+    calendar_feed_token = db.Column(db.String(255), nullable=True, unique=True, index=True)
     notification_task_due_enabled = db.Column(db.Boolean, nullable=False, default=True)
     notification_monthly_winner_enabled = db.Column(db.Boolean, nullable=False, default=True)
 
@@ -60,6 +62,11 @@ class User(UserMixin, TimestampMixin, db.Model):
     def check_password(self, password: str) -> bool:
         return check_password_hash(self.password_hash, password)
 
+    def ensure_calendar_feed_token(self) -> str:
+        if not self.calendar_feed_token:
+            self.calendar_feed_token = secrets.token_urlsafe(32)
+        return self.calendar_feed_token
+
     @property
     def display_avatar(self) -> str:
         return self.avatar_path or "images/avatars/default.svg"

app/routes/main.py

@@ -3,9 +3,11 @@ from __future__ import annotations
 from functools import lru_cache
 from pathlib import Path
 
-from flask import Blueprint, current_app, redirect, send_from_directory, url_for
+from flask import Blueprint, Response, current_app, redirect, send_from_directory, url_for
 from flask_login import current_user
 
+from ..models import User
+from ..services.calendar_feeds import build_calendar_feed
 
 bp = Blueprint("main", __name__)
 
@@ -39,6 +41,16 @@ def uploads(filename: str):
     return send_from_directory(current_app.config["UPLOAD_FOLDER"], filename)
 
 
+@bp.route("/calendar-feed/<token>.ics")
+def calendar_feed(token: str):
+    user = User.query.filter_by(calendar_feed_token=token).first_or_404()
+    body = build_calendar_feed(user, url_for("tasks.my_tasks", _external=True))
+    response = Response(body, content_type="text/calendar; charset=utf-8")
+    response.headers["Content-Disposition"] = 'inline; filename="putzliga.ics"'
+    response.headers["Cache-Control"] = "private, max-age=300"
+    return response
+
+
 @lru_cache(maxsize=64)
 def load_icon_svg(name: str, static_folder: str) -> str:
     path = Path(static_folder) / "icons" / f"{name}.svg"

app/routes/settings.py

@@ -45,6 +45,7 @@ def _save_avatar(file_storage) -> str:
 @bp.route("", methods=["GET", "POST"])
 @login_required
 def index():
+    current_user.ensure_calendar_feed_token()
     form = SettingsProfileForm(original_email=current_user.email, obj=current_user)
     admin_form = AdminUserForm(prefix="admin")
     quick_task_config_form = QuickTaskConfigForm(prefix="quickconfig")
@@ -80,6 +81,7 @@ def index():
         quick_task_config=quick_task_config,
         users=User.query.order_by(User.is_admin.desc(), User.name.asc()).all(),
         earned_badges=earned_badges_for_user(current_user.id),
+        calendar_feed_url=url_for("main.calendar_feed", token=current_user.calendar_feed_token, _external=True),
         push_ready=push_enabled(),
         has_subscription=bool(subscriptions),
         settings_tabs=_settings_tabs(),
@@ -87,6 +89,16 @@ def index():
     )
 
 
+@bp.route("/calendar-feed/regenerate", methods=["POST"])
+@login_required
+def regenerate_calendar_feed():
+    current_user.calendar_feed_token = None
+    current_user.ensure_calendar_feed_token()
+    db.session.commit()
+    flash("Dein persönlicher Kalender-Link wurde neu erzeugt.", "success")
+    return redirect(url_for("settings.index"))
+
+
 @bp.route("/badges")
 @login_required
 def badges():

app/services/bootstrap.py

@@ -17,8 +17,18 @@ def ensure_schema_and_admins() -> None:
         db.session.execute(text("ALTER TABLE user ADD COLUMN is_admin BOOLEAN NOT NULL DEFAULT 0"))
         db.session.commit()
 
+    if "calendar_feed_token" not in column_names:
+        db.session.execute(text("ALTER TABLE user ADD COLUMN calendar_feed_token VARCHAR(255)"))
+        db.session.commit()
+
     ensure_app_settings()
 
+    users_without_feed = User.query.filter(User.calendar_feed_token.is_(None)).all()
+    if users_without_feed:
+        for user in users_without_feed:
+            user.ensure_calendar_feed_token()
+        db.session.commit()
+
     admin_exists = User.query.filter_by(is_admin=True).first()
     if admin_exists:
         return

app/services/calendar_feeds.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime, time, timedelta
+
+from ..models import TaskInstance, User
+
+
+def _ics_escape(value: str | None) -> str:
+    text = (value or "").replace("\\", "\\\\")
+    text = text.replace(";", "\\;").replace(",", "\\,")
+    text = text.replace("\r\n", "\\n").replace("\n", "\\n").replace("\r", "\\n")
+    return text
+
+
+def _format_date(value) -> str:
+    return value.strftime("%Y%m%d")
+
+
+def _format_timestamp(value: datetime | None) -> str:
+    timestamp = value or datetime.now(UTC).replace(tzinfo=None)
+    return timestamp.strftime("%Y%m%dT%H%M%SZ")
+
+
+def build_calendar_feed(user: User, base_url: str) -> str:
+    tasks = (
+        TaskInstance.query.filter_by(assigned_user_id=user.id)
+        .order_by(TaskInstance.due_date.asc(), TaskInstance.id.asc())
+        .all()
+    )
+
+    lines = [
+        "BEGIN:VCALENDAR",
+        "VERSION:2.0",
+        "PRODID:-//hnz.io//Putzliga//DE",
+        "CALSCALE:GREGORIAN",
+        "METHOD:PUBLISH",
+        f"X-WR-CALNAME:{_ics_escape(f'Putzliga - {user.name}')}",
+        f"X-WR-CALDESC:{_ics_escape('Persoenlicher Aufgabenfeed aus Putzliga')}",
+    ]
+
+    for task in tasks:
+        due_end = task.due_date + timedelta(days=1)
+        description = _ics_escape(task.description)
+        lines.extend(
+            [
+                "BEGIN:VEVENT",
+                f"UID:taskinstance-{task.id}@putzliga",
+                f"DTSTAMP:{_format_timestamp(task.updated_at)}",
+                f"LAST-MODIFIED:{_format_timestamp(task.updated_at)}",
+                f"SUMMARY:{_ics_escape(task.title)}",
+                f"DESCRIPTION:{description}",
+                f"DTSTART;VALUE=DATE:{_format_date(task.due_date)}",
+                f"DTEND;VALUE=DATE:{_format_date(due_end)}",
+                f"URL:{_ics_escape(base_url)}",
+                "END:VEVENT",
+            ]
+        )
+
+    lines.append("END:VCALENDAR")
+    return "\r\n".join(lines) + "\r\n"

app/templates/settings/index.html

@@ -95,6 +95,25 @@
     {% endif %}
   </section>
 
+  <section class="panel">
+    <p class="eyebrow">Kalender-Abo</p>
+    <h2>Persönlicher ICS-Feed</h2>
+    <p class="muted">Dieser Read-only-Link zeigt in externen Kalendern nur Aufgaben an, die dir zugewiesen sind. Exportiert werden nur Titel, Beschreibung und Fälligkeitsdatum.</p>
+    <div class="push-box">
+      <div class="field">
+        <label for="calendarFeedUrl">Persönliche Kalender-URL</label>
+        <input id="calendarFeedUrl" type="text" value="{{ calendar_feed_url }}" readonly>
+      </div>
+      <div class="form-actions">
+        <a class="button button--secondary" href="{{ calendar_feed_url }}" target="_blank" rel="noreferrer">ICS öffnen</a>
+        <form method="post" action="{{ url_for('settings.regenerate_calendar_feed') }}">
+          <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
+          <button type="submit" class="button button--ghost">Link neu erzeugen</button>
+        </form>
+      </div>
+    </div>
+  </section>
+
   {% if current_user.is_admin %}
     <section class="panel">
       <p class="eyebrow">Admin</p>