Prototype asgi support

appname/asgi.py

@@ -9,8 +9,29 @@
 
 import os
 
+from channels.auth import AuthMiddlewareStack
+from channels.routing import ProtocolTypeRouter, URLRouter
+from channels.security.websocket import AllowedHostsOriginValidator
 from django.core.asgi import get_asgi_application
+from django.urls import re_path
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "appname.settings")
 
-application = get_asgi_application()
+django_asgi_app = get_asgi_application()
+
+from appname import consumers  # noqa: E402
+
+application = ProtocolTypeRouter(
+    {
+        "http": django_asgi_app,
+        "websocket": AllowedHostsOriginValidator(
+            AuthMiddlewareStack(
+                URLRouter(
+                    [
+                        re_path(r"^ws/hello/$", consumers.HelloConsumer.as_asgi()),
+                    ]
+                )
+            )
+        ),
+    }
+)

appname/consumers.py

@@ -0,0 +1,18 @@
+from channels.generic.websocket import WebsocketConsumer
+
+
+class HelloConsumer(WebsocketConsumer):
+    groups = ["broadcast"]
+
+    def connect(self):
+        self.user = self.scope["user"]
+        self.accept()
+
+    def receive(self, text_data=None, bytes_data=None):
+        if self.user.is_authenticated:
+            self.send(text_data=f"Hello {self.user.first_name:} {self.user.last_name}!")
+        else:
+            self.send(text_data="Hello anonymous!")
+
+    def disconnect(self, close_code):
+        ...

appname/core/views.py

@@ -15,6 +15,10 @@ def terms(request):
     return TemplateResponse(request, "core/terms.html", {})
 
 
+def websocket(request):
+    return TemplateResponse(request, "core/websocket.html", {})
+
+
 def feedback(request):
     form = UserFeedbackForm()
 

appname/settings.py

@@ -20,6 +20,7 @@
 # Application definition
 
 INSTALLED_APPS = [
+    "daphne",
     "django.contrib.admin",
     "django.contrib.auth",
     "django.contrib.contenttypes",
@@ -30,6 +31,7 @@
     "django.contrib.flatpages",
     "django.forms",
     "django_extensions",
+    "channels",
     "allauth",
     "allauth.account",
     "rest_framework",
@@ -64,19 +66,21 @@
 ]
 
 if DEBUG:
-    MIDDLEWARE += [
-        "silk.middleware.SilkyMiddleware",
-        "django_browser_reload.middleware.BrowserReloadMiddleware",
-    ]
     DJANGO_DEBUG_TOOLBAR = env.bool("DJANGO_DEBUG_TOOLBAR")
     if DJANGO_DEBUG_TOOLBAR:
         MIDDLEWARE += [
             "debug_toolbar.middleware.DebugToolbarMiddleware",
         ]
+
     # Set to True only when analyzing queries
     # as it can have unexpected behavior
     SILKY_ANALYZE_QUERIES = False
 
+    MIDDLEWARE += [
+        "silk.middleware.SilkyMiddleware",
+        "django_browser_reload.middleware.BrowserReloadMiddleware",
+    ]
+
 ROOT_URLCONF = "appname.urls"
 
 TEMPLATES = [
@@ -97,6 +101,9 @@
 ]
 
 WSGI_APPLICATION = "appname.wsgi.application"
+ASGI_APPLICATION = "appname.asgi.application"
+
+CHANNEL_LAYERS = {"default": {"BACKEND": "channels.layers.InMemoryChannelLayer"}}
 
 # Database
 
@@ -338,7 +345,7 @@
     }
     LOGGING["loggers"]["django_structlog"]["handlers"] = ["flat_line_file"]
     LOGGING["loggers"]["django"] = {
-        "handlers": ["rich_console", "flat_line_file"],
+        "handlers": ["flat_line_file"],
         "level": "INFO",
     }
     # LOGGING["loggers"]["django.db.backends"] = {

appname/urls.py

@@ -25,6 +25,7 @@
     path("", views.index, name="index"),
     path("terms/", views.terms, name="terms"),
     path("feedback/", views.feedback, name="feedback"),
+    path("websocket/", views.websocket, name="websocket"),
 ]
 
 if settings.DEBUG:

deployment/ansible/provision.yml

@@ -258,7 +258,7 @@
           Group=caddy
           WorkingDirectory=/srv/{{ app_name }}
           ExecReload=/bin/kill -HUP $MAINPID
-          ExecStart=/usr/local/bin/poetry run gunicorn appname.wsgi:application --workers 2 --bind unix:/var/run/{{ app_name }}/app.sock --access-logfile /var/log/{{ app_name }}/gunicorn_access_log.txt --error-logfile /var/log/{{ app_name }}/gunicorn_error_log.txt
+          ExecStart=/usr/local/bin/poetry run gunicorn appname.asgi:application -k uvicorn.workers.UvicornWorker --workers 2 --bind unix:/var/run/{{ app_name }}/app.sock --access-logfile /var/log/{{ app_name }}/gunicorn_access_log.txt --error-logfile /var/log/{{ app_name }}/gunicorn_error_log.txt
           #Restart=on-failure
           #RestartSec=5s
           KillMode=mixed

pyproject.toml

@@ -23,9 +23,12 @@ pillow = "9.4.0"
 drf-standardized-errors = {extras = ["openapi"], version = "0.12.5"}
 django-cors-headers = "3.14.0"
 rich = "^13.3.5"
+channels = "4.0.0"
+daphne = "4.0.0"
+uvicorn = {extras = ["standard"], version = "^0.22.0"}
 
 [tool.poetry.group.dev.dependencies]
-django-browser-reload = "1.6.0"
+django-browser-reload = "1.10.0"
 django-debug-toolbar = "3.8.1"
 pywatchman = "1.4.1"
 bandit = "1.7.4"

templates/core/index.html

@@ -38,6 +38,9 @@ <h3>
             <tr>
                 <td><a href="/terms/">terms</a></td><td>Terms (requires adding a flatpage)</td>
             </tr>
+            <tr>
+                <td><a href="/websocket/">websocket</a></td><td>Websocket demo</td>
+            </tr>
             <tr>
                 <td><a href="/silk/">silk</a></td><td>Silk profiling tool</td>
             </tr>

templates/core/websocket.html

@@ -0,0 +1,34 @@
+{% extends '_base.html' %}
+{% load i18n %}
+{% block full_title %}{{ PROJECT_NAME }}{% endblock full_title %}
+{% block content %}
+<section class="page page--wide">
+  <h1>
+    Websockets demo
+  </h1>
+  <p>
+    If websocket connection is successful you should see an alert with a message.
+  </p>
+</section>
+<script>
+    const websocket = new WebSocket(
+        'ws://'
+        + window.location.host
+        + '/ws/hello/'
+    )
+    console.log('ws://'
+        + window.location.host
+        + '/ws/hello/')
+    websocket.onopen = function(e) {
+        websocket.send('Sending message from the browser')
+    }
+
+    websocket.onmessage = function(e) {
+        alert(e.data)
+    }
+
+    websocket.onclose = function(e) {
+        console.error('Websocket connection closed')
+    }
+</script>
+{% endblock content %}