final

app/routes.py

@@ -1,6 +1,6 @@
 from flask import Blueprint, render_template, request, flash, redirect, url_for, current_app
 from flask_mail import Message
-from itsdangerous import URLSafeTimedSerializer, SignatureExpired, BadSignature
+from itsdangerous import URLSafeTimedSerializer, SignatureExpired, BadSignature, exc
 from app.extensions import db, mail, limiter
 from app.models import Participant
 import traceback
@@ -20,12 +20,14 @@ def add_user(name, email, looking_for_team, on_waitlist = False):
 
 def send_verification_email(user):
     s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
-    token = s.dumps(user.email, salt='email-confirm-h4tum-ctf-2025')
+    register_token = s.dumps(user.email, salt='email-confirm-h4tum-ctf-2025')
-    link = url_for('main.verify_email', token=token, _external=True)
+    remove_token = s.dumps(user.email, salt='email-remove-h4tum-ctf-2026')
+    register_link = url_for('main.verify_email', token=register_token, _external=True)
+    remove_link = url_for('main.remove_registration', token=remove_token, _external=True)
     logo = url_for('static', filename='h4tum_white.png', _external=True)
     
     msg = Message('Verify your CTF Registration', recipients=[user.email])
-    msg.html = render_template("email.html", user_name=user.name, link=link, logo_url=logo)
+    msg.html = render_template("email.html", user_name=user.name, register_link=register_link, remove_link=remove_link, logo_url=logo)
     mail.send(msg)
     user.num_emails_sent += 1
     db.session.commit()
@@ -111,6 +113,31 @@ def verify_email(token):
     
     return render_template('success.html', message=msg, discord_link=discord_link, discord_token=discord_token)
 
+@bp.route('/remove/<token>')
+@limiter.limit("5 per hour")
+def remove_registration(token):
+    s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
+    try:
+        email = s.loads(token, salt='email-remove-h4tum-ctf-2026', max_age=1209600)
+    except SignatureExpired:
+        return render_template("error.html", error_message="Token expired. Please register again.")
+    except BadSignature:
+        return render_template("error.html", error_message="Invalid token.")
+
+    user = Participant.query.filter_by(email=email).first_or_404()
+
+    if not user:
+        return render_template("error.html", error_message="No user found.")
+    
+    try:
+        db.session.delete(user)
+        db.session.commit()
+        return render_template("deregistered.html", message="Sad to see you go. Comeback next time :D")
+    except:
+        db.session.rollback()
+        return render_template("error.html", error_message="Removing user did not work")
+
+    
 @bp.route('/dsgvo')
 @limiter.exempt
 def dsgvo():

app/templates/deregistered.html

@@ -0,0 +1,14 @@
+{% extends "base.html" %}
+{% block content %}
+<style>
+ .container {
+    text-align: center;
+  }
+</style>
+
+<div class="container">
+  <h1>> Remove user</h1>
+  <h1 style="color:#ffffff;">{{ message }}</h1>
+</div>
+
+{% endblock %}

app/templates/email.html

@@ -30,7 +30,7 @@
                             <table border="0" cellspacing="0" cellpadding="0" align="center">
                                 <tr>
                                     <td align="center" bgcolor="#00ff00" style="padding: 15px 25px;">
-                                        <a href="{{ link }}" target="_blank" style="font-size: 18px; font-weight: bold; color: #000000; text-decoration: none; display: inline-block;">
+                                        <a href="{{ register_link }}" target="_blank" style="font-size: 18px; font-weight: bold; color: #000000; text-decoration: none; display: inline-block;">
                                             CONFIRM MY SPOT
                                         </a>
                                     </td>
@@ -39,6 +39,24 @@
                         </td>
                     </tr>
 
+                    <tr>
+                        <td align="center" style="padding-bottom: 30px; font-size: 16px; line-height: 1.5; text-align: center;">
+                            If you can not attend please deregister using the following link
+                        </td>
+                    </tr>
+                    <tr>
+                        <td align="center" style="padding-bottom: 30px;">
+                            <table border="0" cellspacing="0" cellpadding="0" align="center">
+                                <tr>
+                                    <td align="center" bgcolor="#D32F2F" style="padding: 15px 25px;">
+                                        <a href="{{ remove_link }}" target="_blank" style="font-size: 18px; font-weight: bold; color: #000000; text-decoration: none; display: inline-block;">
+                                           DEREGISTER
+                                        </a>
+                                    </td>
+                                </tr>
+                            </table>
+                        </td>
+                    </tr>
                     <tr>
                         <td align="center" style="padding-top: 20px; border-top: 1px solid #333333; font-size: 12px; color: #888888; text-align: center;">
                             If you didn't request this, you can safely ignore this email.