Add routes:

/messages
/notifications

app/main/routes.py

@@ -16,8 +16,8 @@
 
 from app import db
 from app.main import bp
-from app.main.forms import EditProfileForm, EmptyForm, PostForm, SearchForm
-from app.models import User, Post
+from app.main.forms import EditProfileForm, EmptyForm, PostForm, SearchForm, MessageForm
+from app.models import User, Post, Message, Notification
 
 
 @bp.before_request
@@ -281,3 +281,37 @@ def search():
     # Отображаем страницу поиска с результатами
     return render_template('search.html', title=_('Search'), posts=posts,
                            next_url=next_url, prev_url=prev_url)
+
+
+@bp.route('/messages')
+@login_required
+def messages():
+    current_user.last_message_read_time = datetime.now(timezone.utc)
+    current_user.add_notification('unread_message_count', 0)
+    db.session.commit()
+    page = request.args.get('page', 1, type=int)
+    query = current_user.messages_received.select().order_by(
+        Message.timestamp.desc())
+    messages = db.paginate(query, page=page,
+                           per_page=current_app.config['POSTS_PER_PAGE'],
+                           error_out=False)
+    next_url = url_for('main.messages', page=messages.next_num) \
+        if messages.has_next else None
+    prev_url = url_for('main.messages', page=messages.prev_num) \
+        if messages.has_prev else None
+    return render_template('messages.html', messages=messages.items,
+                           next_url=next_url, prev_url=prev_url)
+
+
+@bp.route('/notifications')
+@login_required
+def notifications():
+    since = request.args.get('since', 0.0, type=float)
+    query = current_user.notifications.select().where(
+        Notification.timestamp > since).order_by(Notification.timestamp.asc())
+    notifications = db.session.scalars(query)
+    return [{
+        'name': n.name,
+        'data': n.get_data(),
+        'timestamp': n.timestamp
+    } for n in notifications]