Django Channels Error: No WebSocket Route Found for ws/student/start-exam/2

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I encountered a ValueError stating "No route found for path 'ws/student/start-exam/2'" when trying to connect via Django Channels. I've set up my WebSocket consumer, routing, ASGI configuration, and settings as shown below. I’m not sure why the route isn’t matching even though I believe my URL patterns are correct. Any insights on how to resolve this issue would be appreciated.

Here’s the relevant code:

consumer.py

PYTHON
import json
import asyncio
from datetime import datetime, timedelta
from channels.generic.websocket import AsyncWebsocketConsumer
from django.db.models import ObjectDoesNotExist

class CountdownConsumer(AsyncWebsocketConsumer):
    async def connect(self):
        self.id = self.scope['url_route']['kwargs']['id']
        self.running = True  # Flag to control the countdown loop
        await self.channel_layer.group_add(self.id, self.channel_name)
        await self.accept()

    # Send initial countdown data
    asyncio.create_task(self.send_countdown())

    async def disconnect(self, close_code):
        self.running = False
        await self.channel_layer.group_discard(self.id, self.channel_name)

    async def send_countdown(self):
        from .models import Course  # Import your model here

        try:
            # Fetch the timer's duration
            timer = await asyncio.to_thread(Course.objects.get, id=self.id)
            if not isinstance(timer.time_duration, timedelta):
                raise ValueError("time_duration must be a timedelta object")

            # Calculate end time
            end_time = datetime.now() + timer.time_duration

            # Loop to send countdown updates
            while self.running:
                remaining = (end_time - datetime.now()).total_seconds()

                if remaining <= 0:
                    await self.send(json.dumps({'remaining': 0}))
                    break

                await self.send(json.dumps({'remaining': int(remaining)}))
                await asyncio.sleep(1)  # Update every second

        except ObjectDoesNotExist:
            await self.send(json.dumps({'error': 'Timer not found'}))
        except Exception as e:
            await self.send(json.dumps({'error': str(e)}))

start-exam.html

HTML
{% extends 'student/studentbase.html' %}
{% block content %}
{% load static %}

Time left:

Course: {{course.course_name}}
-------------------------------

{% for q in questions %}

### {{ forloop.counter }}. {{ q.question }}

#### [{{ q.marks }} Marks]

    <div class="form-check mx-4 d-flex align-items-center">
        <input class="form-check-input" type="radio" name="{{ forloop.counter }}" id="{{ q.option1 }}" value="Option1"> 
        <label class="form-check-label ml-3" for="option1">
          {{ q.option1 }}
        </label>
    </div>

    <div class="form-check mx-4 d-flex align-items-center">
        <input class="form-check-input" type="radio" name="{{ forloop.counter }}" id="{{ q.option2 }}" value="Option2"> 
        <label class="form-check-label ml-3" for="option2">
          {{ q.option2 }}
        </label>
    </div>

    <div class="form-check mx-4 d-flex align-items-center">
        <input class="form-check-input" type="radio" name="{{ forloop.counter }}" id="{{ q.option3 }}" value="Option3"> 
        <label class="form-check-label ml-3" for="option3">
          {{ q.option3 }}
        </label>
    </div>

    <div class="form-check mx-4 d-flex align-items-center">
        <input class="form-check-input" type="radio" name="{{ forloop.counter }}" id="{{ q.option4 }}" value="Option4"> 
        <label class="form-check-label ml-3" for="option4">
          {{ q.option4 }}
        </label>
    </div>

{% endfor %}
<input class="btn btn-primary btn-lg" style="border-radius: 0%;" type="submit" value="Submit Answers">

<button class="btn btn-danger">go back</button>
</form>

{% endblock content %}

asgi.py

PYTHON
"""
ASGI config for ExamManagementSystem project.

It exposes the ASGI callable as a module-level variable named `application`.

For more information on this file, see

![Image](https://us1.discourse-cdn.com/flex026/uploads/djangoproject/original/3X/c/8/c8b5ef7626f1ddc7a1eefc8488235c9a2a7dd81c.png)
[Django Project](https://docs.djangoproject.com/en/5.1/howto/deployment/asgi/)

![Image](https://us1.discourse-cdn.com/flex026/uploads/djangoproject/original/3X/0/8/0869b74cbab83cec132a76be0be7408428bab005.png)

### [How to deploy with ASGI | Django documentation](https://docs.djangoproject.com/en/5.1/howto/deployment/asgi/)

The web framework for perfectionists with deadlines.
"""

import os

from django.core.asgi import get_asgi_application
from channels.routing import ProtocolTypeRouter, URLRouter
from channels.auth import AuthMiddlewareStack
import exam.routing
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'ExamManagementSystem.settings')

application = ProtocolTypeRouter({
    "http": get_asgi_application(),
    "websocket": AuthMiddlewareStack(
        URLRouter(
            exam.routing.websocket_urlpatterns
        )
    ),
})

settings.py

PYTHON
"""
Django settings for ExamManagementSystem project.

Generated by 'django-admin startproject' using Django 5.1.3.

For more information on this file, see

![Image](https://us1.discourse-cdn.com/flex026/uploads/djangoproject/original/3X/c/8/c8b5ef7626f1ddc7a1eefc8488235c9a2a7dd81c.png)
[Django Project](https://docs.djangoproject.com/en/5.1/topics/settings/)

![Image](https://us1.discourse-cdn.com/flex026/uploads/djangoproject/original/3X/0/8/0869b74cbab83cec132a76be0be7408428bab005.png)

### [Django settings | Django documentation](https://docs.djangoproject.com/en/5.1/topics/settings/)

The web framework for perfectionists with deadlines.
"""

import os
from pathlib import Path

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent
TEMPLATE_DIR = os.path.join(BASE_DIR, 'templates')
STATIC_DIR = os.path.join(BASE_DIR, 'static')
MEDIA_ROOT = os.path.join(BASE_DIR, 'static')

# Quick-start development settings - unsuitable for production
# See [Deployment checklist | Django documentation | Django](https://docs.djangoproject.com/en/5.1/howto/deployment/checklist/)
SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'django-insecure-50#eg*ag5^2nj4s#hlx15(m+!xi*6+cb05lr%l6ata46n(8w$u'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True
ALLOWED_HOSTS = []

# Application definition
INSTALLED_APPS = [
    'channels',
    'daphne',
    'jazzmin',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'teacher',
    'student',
    'exam',
    'widget_tweaks',
    'crispy_forms',
    'crispy_bootstrap4',
]
ASGI_APPLICATION = 'ExamManagementSystem.asgi.application'
CRISPY_TEMPLATE_PACK = 'bootstrap4'

CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels.layers.InMemoryChannelLayer",
    },
}
MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

JAZZMIN_SETTINGS = {
    "site_title": "Admin Portal",
    "site_header":  "Admin Portal",
    "site_brand": "Admin Dashboard",
    "login_logo": None,
    "login_logo_dark": None,
    "site_logo_classes": "img-circle",
    "site_icon": None,
    "welcome_sign": "Welcome to the Exam management",
    "search_model": ["auth.User", "auth.Group"],
    "user_avatar": None,
    "topmenu_links": [
        {"name": "Home",  "url": "admin:index", "permissions": ["auth.view_user"]},
        {"name": "Support", "url": "https://github.com/farridav/django-jazzmin/issues", "new_window": True},
        {"model": "auth.User"},
        {"app": "student"},
    ],
    "show_sidebar": True,
    "navigation_expanded": True,
    "hide_apps": [],
    "hide_models": [],
    "order_with_respect_to": ["auth", "books", "books.author", "books.book"],
    "custom_links": {
        "books": [{
            "name": "Make Messages", 
            "url": "make_messages", 
            "icon": "fas fa-comments",
            "permissions": ["books.view_book"]
        }]
    },
    "icons": {
        "auth": "fas fa-users-cog",
        "auth.user": "fas fa-user",
        "auth.Group": "fas fa-users",
    },
    "default_icon_parents": "fas fa-chevron-circle-right",
    "default_icon_children": "fas fa-circle",
    "related_modal_active": False,
    "custom_css": None,
    "custom_js": None,
    "use_google_fonts_cdn": True,
    "show_ui_builder": False,
    "changeform_format": "horizontal_tabs",
    "changeform_format_overrides": {"auth.user": "collapsible", "auth.group": "vertical_tabs"},
}

ROOT_URLCONF = 'ExamManagementSystem.urls'
AUTH_USER_MODEL = 'student.CustomUser'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [TEMPLATE_DIR],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'ExamManagementSystem.wsgi.application'

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
        'OPTIONS': {
            'min_length': 5,
        }
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_TZ = True

STATIC_URL = '/static/'
STATICFILES_DIRS = [
    STATIC_DIR,
]
LOGIN_REDIRECT_URL = '/'

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

routing.py

PYTHON
from django.urls import re_path
from . import consumers

websocket_urlpatterns = [
    re_path(r'ws/student/start-exam/(?P<id>\d+)/$', consumers.CountdownConsumer.as_asgi())<NL:]

Comments 0

•

Answers 1

•

1 Answer

Answer by StackOverflow TychoAI Agent • 9 days ago

Django Channels WebSocket Route Issue

I've identified the issue in your WebSocket routing configuration. The problem is in your routing.py file where there's a syntax error in the websocket_urlpatterns list.

The Issue

In your routing.py file, there's a syntax error at the end of the list:

PYTHON
websocket_urlpatterns = [
    re_path(r'ws/student/start-exam/(?P<id>\d+)/$', consumers.CountdownConsumer.as_asgi())
:]  # <-- Syntax error here

The closing bracket has a colon after it, which is invalid Python syntax.

The Fix

Correct the syntax error by removing the colon:

PYTHON
websocket_urlpatterns = [
    re_path(r'ws/student/start-exam/(?P<id>\d+)/$', consumers.CountdownConsumer.as_asgi())
]  # Remove the colon

Additional Considerations

WebSocket URL Format: Make sure you're connecting to the WebSocket with the exact path format, including the trailing slash. Your route is defined as ws/student/start-exam/2/ but your error message suggests you might be trying to connect to ws/student/start-exam/2 (without the trailing slash).
Consumer Connection Method: In your CountdownConsumer, the asyncio.create_task(self.send_countdown()) line is outside any method, which could cause issues. It should be inside the connect() method:

PYTHON
async def connect(self):
    self.id = self.scope['url_route']['kwargs']['id']
    self.running = True  # Flag to control the countdown loop
    await self.channel_layer.group_add(self.id, self.channel_name)
    await self.accept()
    
    # Start the countdown task after accepting the connection
    asyncio.create_task(self.send_countdown())

JavaScript Connection: Make sure your JavaScript code is connecting to the WebSocket correctly. For example:

JAVASCRIPT
const socket = new WebSocket(`ws://${window.location.host}/ws/student/start-exam/2/`);

After making these changes, your WebSocket connection should work properly.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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