WIP: long polling support #1

Draft
perelman wants to merge 10 commits from feature/long-poll-status into history/short-polling-only
8 changed files with 128 additions and 6 deletions

1
.gitignore vendored
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@ -60,3 +60,4 @@ target/
# sqlite database
*.sqlite3
fear_tracker/migrations

16
fear_tracker/routing.py Normal file
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@ -0,0 +1,16 @@
from channels.http import AsgiHandler
from channels.routing import ProtocolTypeRouter, URLRouter
from django.conf.urls import url
from . import views
application = ProtocolTypeRouter({
"http": URLRouter([
url(r'^(?P<access_code>[a-zA-Z]{6})/', URLRouter([
url(r"status/(?P<hashcode>[a-z0-9]{64})/",
views.StatusLongPollConsumer, name='status'),
])),
url(r"", AsgiHandler),
]),
})

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@ -360,13 +360,23 @@
el.addEventListener("change", formElementChanged);
}
setInterval(function() {
function checkStatus() {
if(activeRequests.size != 0) return;
// From https://stackoverflow.com/a/50101022
const abort = new AbortController();
const signal = abort.signal;
// 50 second timeout:
const timeoutId = setTimeout(() => abort.abort(), 50000);
fetch(new Request("{% url 'status' access_code=access_code %}"
+ (statusObj.hash != ""
? statusObj.hash + "/"
: "")))
: "")),
{signal})
.then(response => {
clearTimeout(timeoutId);
if(response.status === 304) {
// TODO Just skip the next step?
return statusObj;
@ -381,8 +391,14 @@
} else {
statusObj = data;
}
})
.then(checkStatus)
.catch(() => {
// If something went wrong, wait a few seconds before retrying.
setTimeout(checkStatus, 5000);
});
}, 5000);
}
checkStatus();
});
</script>
{% endif %}

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@ -27,7 +27,5 @@ urlpatterns = [
path('update/', views.update_game, name='update_game'),
path('qr/', views.qr_code, name='qr_code'),
path('status/', views.status, name='status'),
url('^status/(?P<hashcode>[a-z0-9]{64})/',
views.status, name='status'),
])),
])),
]

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@ -5,6 +5,11 @@ import hashlib
import json
import qrcode
from asgiref.sync import async_to_sync
from channels.generic.http import AsyncHttpConsumer
from channels.layers import get_channel_layer
from django.db import transaction
from django.http import HttpResponse
from django.shortcuts import get_object_or_404, redirect, render
@ -288,12 +293,22 @@ def handle_game_request(request, game, update):
res['value'] = current_value
else:
res = {'success': True}
async_to_sync(get_channel_layer().group_send)(
"%s_status" % game.access_code,
{"type": "fear_tracker.invalidate_status"})
return HttpResponse(json.dumps(res))
players = get_players_with_fear(game, current_phase, players)
status_obj = game_status_object(game, current_phase, players)
status_string = json.dumps(status_obj)
async_to_sync(get_channel_layer().group_send)(
"%s_status" % game.access_code, {
"type": "fear_tracker.hashcode_seen",
"hashcode": status_obj['hash'],
"status_string": status_string,
})
for player in players.values():
info = player.fear
if not info:
@ -324,4 +339,57 @@ def status(request, game, hashcode=None):
return HttpResponse(status=HTTPStatus.NOT_MODIFIED)
else:
status_string = json.dumps(status_obj)
async_to_sync(get_channel_layer().group_send)(
"%s_status" % game.access_code, {
"type": "fear_tracker.hashcode_seen",
"hashcode": status_obj['hash'],
"status_string": status_string,
})
return HttpResponse(status_string)
class StatusLongPollConsumer(AsyncHttpConsumer):
async def handle(self, body):
self.access_code = self.scope["url_route"]["kwargs"]["access_code"]
self.hashcode = self.scope["url_route"]["kwargs"]["hashcode"]
await self.channel_layer.group_add("%s_status" % self.access_code,
self.channel_name)
await self.channel_layer.group_send(
"%s_status" % self.access_code, {
"type": "fear_tracker.hashcode_seen",
"hashcode": self.hashcode,
})
async def http_request(self, message):
"""
Async entrypoint - concatenates body fragments and hands off control
to ``self.handle`` when the body has been completely received.
"""
if "body" in message:
self.body.append(message["body"])
if not message.get("more_body"):
await self.handle(b"".join(self.body))
async def disconnect(self):
await self.channel_layer.group_discard("%s_status" % self.access_code,
self.channel_name)
async def fear_tracker_hashcode_seen(self, event):
if self.hashcode != event["hashcode"]:
if event["status_string"]:
body = event["status_string"].encode('utf-8')
await self.send_response(200, body)
await self.disconnect()
await self.channel_layer.group_send(
"%s_status" % self.access_code, {
"type": "fear_tracker.invalidate_status",
})
async def fear_tracker_invalidate_status(self, event):
no_hash_status = reverse('status',
kwargs={'access_code': self.access_code})
await self.send_response(302, b'', headers=[
(b"Location", no_hash_status.encode('utf-8'))
])
await self.http_disconnect(None)

12
fear_tracker_site/asgi.py Normal file
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@ -0,0 +1,12 @@
"""
ASGI entrypoint. Configures Django and then runs the application
defined in the ASGI_APPLICATION setting.
"""
import os
import django
from channels.routing import get_default_application
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "fear_tracker_site.settings")
django.setup()
application = get_default_application()

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@ -0,0 +1,3 @@
import fear_tracker.routing
application = fear_tracker.routing.application

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@ -31,6 +31,7 @@ ALLOWED_HOSTS = []
# Application definition
INSTALLED_APPS = [
'channels',
'fear_tracker',
'django.contrib.admin',
'django.contrib.auth',
@ -69,6 +70,7 @@ TEMPLATES = [
]
WSGI_APPLICATION = 'fear_tracker_site.wsgi.application'
ASGI_APPLICATION = 'fear_tracker_site.routing.application'
# Database
@ -81,6 +83,12 @@ DATABASES = {
}
}
CHANNEL_LAYERS = {
"default": {
"BACKEND": "channels.layers.InMemoryChannelLayer"
}
}
# Password validation
# https://docs.djangoproject.com/en/2.2/ref/settings/#auth-password-validators