139 lines
4.8 KiB
Python
139 lines
4.8 KiB
Python
import itertools
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import json
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from asgiref.inmemory import ChannelLayer
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from channels import Channel, Group
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from channels.auth import channel_session_user, channel_session_user_from_http
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from django.apps import apps
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from django.db import transaction
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from django.utils import timezone
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from ..users.auth import AnonymousUser
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from ..users.models import User
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from .access_permissions import BaseAccessPermissions
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def get_logged_in_users():
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"""
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Helper to get all logged in users.
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Only works with the OpenSlides session backend.
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"""
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return User.objects.exclude(session=None).filter(session__expire_date__gte=timezone.now()).distinct()
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def get_model_from_collection_string(collection_string):
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"""
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Returns a model class which belongs to the argument collection_string.
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"""
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def model_generator():
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"""
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Yields all models of all apps.
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"""
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for app_config in apps.get_app_configs():
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for model in app_config.get_models():
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yield model
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for model in model_generator():
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try:
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model_collection_string = model.get_collection_string()
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except AttributeError:
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# Skip models which do not have the method get_collection_string.
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pass
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else:
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if model_collection_string == collection_string:
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# The model was found.
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break
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else:
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# No model was found in all apps.
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raise ValueError('Invalid message. A valid collection_string is missing.')
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return model
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# Connected to websocket.connect
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@channel_session_user_from_http
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def ws_add(message):
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"""
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Adds the websocket connection to a group specific to the connecting user.
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The group with the name 'user-None' stands for all anonymous users.
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"""
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Group('user-{}'.format(message.user.id)).add(message.reply_channel)
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# Connected to websocket.disconnect
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@channel_session_user
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def ws_disconnect(message):
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Group('user-{}'.format(message.user.id)).discard(message.reply_channel)
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def send_data(message):
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"""
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Informs all users about changed data.
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The argument message has to be a dict with the keywords collection_string
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(string), pk (positive integer), id_deleted (boolean) and dispatch_uid
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(string).
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"""
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for access_permissions in BaseAccessPermissions.get_all():
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if access_permissions.get_dispatch_uid() == message['dispatch_uid']:
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break
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else:
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raise ValueError('Invalid message. A valid dispatch_uid is missing.')
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if not message['is_deleted']:
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Model = get_model_from_collection_string(message['collection_string'])
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instance = Model.objects.get(pk=message['pk'])
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full_data = access_permissions.get_full_data(instance)
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# Loop over all logged in users and the anonymous user.
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for user in itertools.chain(get_logged_in_users(), [AnonymousUser()]):
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channel = Group('user-{}'.format(user.id))
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output = {
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'collection': message['collection_string'],
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'id': message['pk'], # == instance.get_rest_pk()
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'action': 'deleted' if message['is_deleted'] else 'changed'}
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if not message['is_deleted']:
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data = access_permissions.get_restricted_data(full_data, user)
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if data is None:
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# There are no data for the user so he can't see the object. Skip him.
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continue
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output['data'] = data
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channel.send({'text': json.dumps(output)})
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def inform_changed_data(instance, is_deleted=False):
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try:
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root_instance = instance.get_root_rest_element()
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except AttributeError:
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# Instance has no method get_root_rest_element. Just ignore it.
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pass
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else:
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# If currently there is an open database transaction, then the following
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# function is only called, when the transaction is commited. If there
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# is currently no transaction, then the function is called immediately.
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def send_autoupdate():
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try:
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Channel('autoupdate.send_data').send({
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'collection_string': root_instance.get_collection_string(),
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'pk': root_instance.pk,
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'is_deleted': is_deleted and instance == root_instance,
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'dispatch_uid': root_instance.get_access_permissions().get_dispatch_uid()})
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except ChannelLayer.ChannelFull:
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pass
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transaction.on_commit(send_autoupdate)
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def inform_changed_data_receiver(sender, instance, **kwargs):
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"""
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Receiver for the inform_changed_data function to use in a signal.
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"""
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inform_changed_data(instance)
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def inform_deleted_data_receiver(sender, instance, **kwargs):
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"""
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Receiver for the inform_changed_data function to use in a signal.
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"""
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inform_changed_data(instance, is_deleted=True)
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