Add asynchronous examples (#1819)

salomvary · salomvary · commit 49624ea1d233 · 2023-09-19T11:25:05.000+02:00
diff --git a/example/README.rst b/example/README.rst
@@ -46,3 +46,13 @@ environment variable::
 
     $ DB_BACKEND=postgresql python example/manage.py migrate
     $ DB_BACKEND=postgresql python example/manage.py runserver
+
+Using an asynchronous (ASGI) server:
+
+Install [Daphne](https://pypi.org/project/daphne/) first:
+
+    $ python -m pip install daphne
+
+Then run the Django development server:
+
+    $ ASYNC_SERVER=true python example/manage.py runserver
diff --git a/example/asgi.py b/example/asgi.py
@@ -0,0 +1,9 @@
+"""ASGI config for example project."""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "example.settings")
+
+application = get_asgi_application()
diff --git a/example/settings.py b/example/settings.py
@@ -16,6 +16,7 @@
 # Application definition
 
 INSTALLED_APPS = [
+    *(["daphne"] if os.getenv("ASYNC_SERVER", False) else []),
     "django.contrib.admin",
     "django.contrib.auth",
     "django.contrib.contenttypes",
@@ -60,6 +61,7 @@
 USE_TZ = True
 
 WSGI_APPLICATION = "example.wsgi.application"
+ASGI_APPLICATION = "example.asgi.application"
 
 DEBUG_TOOLBAR_CONFIG = {"ROOT_TAG_EXTRA_ATTRS": "data-turbo-permanent hx-preserve"}
 
@@ -97,3 +99,26 @@
     }
 
 STATICFILES_DIRS = [os.path.join(BASE_DIR, "example", "static")]
+
+LOGGING = {
+    "version": 1,
+    "disable_existing_loggers": False,
+    "handlers": {
+        "console": {
+            "class": "logging.StreamHandler",
+        },
+    },
+    "root": {
+        "handlers": ["console"],
+        "level": "WARNING",
+    },
+    "loggers": {
+        # Log when an asynchronous handler is adapted for middleware.
+        # See warning here: https://docs.djangoproject.com/en/4.2/topics/async/#async-views
+        "django.request": {
+            "handlers": ["console"],
+            "level": os.getenv("DJANGO_REQUEST_LOG_LEVEL", "INFO"),
+            "propagate": False,
+        },
+    },
+}
diff --git a/example/templates/async_db.html b/example/templates/async_db.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta http-equiv="content-type" content="text/html; charset=utf-8">
+    <title>Async DB</title>
+  </head>
+  <body>
+    <h1>Async DB</h1>
+    <p>
+      <span>Value </span>
+      <span>{{ user_count }}</span>
+    </p>
+  </body>
+</html>
diff --git a/example/urls.py b/example/urls.py
@@ -2,10 +2,13 @@
 from django.urls import include, path
 from django.views.generic import TemplateView
 
-from example.views import increment
+from example.views import async_db, async_db_concurrent, async_home, increment
 
 urlpatterns = [
     path("", TemplateView.as_view(template_name="index.html"), name="home"),
+    path("async/", async_home, name="async_home"),
+    path("async/db/", async_db, name="async_db"),
+    path("async/db-concurrent/", async_db_concurrent, name="async_db_concurrent"),
     path("jquery/", TemplateView.as_view(template_name="jquery/index.html")),
     path("mootools/", TemplateView.as_view(template_name="mootools/index.html")),
     path("prototype/", TemplateView.as_view(template_name="prototype/index.html")),
diff --git a/example/views.py b/example/views.py
@@ -1,4 +1,9 @@
+import asyncio
+
+from asgiref.sync import sync_to_async
+from django.contrib.auth.models import User
 from django.http import JsonResponse
+from django.shortcuts import render
 
 
 def increment(request):
@@ -8,3 +13,23 @@ def increment(request):
         value = 1
     request.session["value"] = value
     return JsonResponse({"value": value})
+
+
+async def async_home(request):
+    return await sync_to_async(render)(request, "index.html")
+
+
+async def async_db(request):
+    user_count = await User.objects.acount()
+
+    return await sync_to_async(render)(request, "async_db.html", {"user_count": user_count})
+
+
+async def async_db_concurrent(request):
+    # Do database queries concurrently
+    (user_count, _) = await asyncio.gather(
+        User.objects.acount(),
+        User.objects.filter(username="test").acount()
+    )
+
+    return await sync_to_async(render)(request, "async_db.html", {"user_count": user_count})
