252 lines
7.7 KiB
Python
252 lines
7.7 KiB
Python
import threading
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from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
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from asgiref.sync import async_to_sync
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from channels.layers import get_channel_layer
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from django.db.models import Model
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from mypy_extensions import TypedDict
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from .cache import element_cache, get_element_id
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from .projector import get_projector_data
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from .utils import get_model_from_collection_string
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class ElementBase(TypedDict):
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id: int
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collection_string: str
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full_data: Optional[Dict[str, Any]]
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class Element(ElementBase, total=False):
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"""
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Data container to handle one root rest element for the autoupdate, history
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and caching process.
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The fields `id`, `collection_string` and `full_data` are required, the other
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fields are optional.
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if full_data is None, it means, that the element was deleted. If reload is
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True, full_data is ignored and reloaded from the database later in the
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process.
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"""
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information: List[str]
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restricted: bool
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user_id: Optional[int]
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disable_history: bool
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reload: bool
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AutoupdateFormat = TypedDict(
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"AutoupdateFormat",
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{
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"changed": Dict[str, List[Dict[str, Any]]],
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"deleted": Dict[str, List[int]],
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"from_change_id": int,
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"to_change_id": int,
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"all_data": bool,
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},
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)
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def inform_changed_data(
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instances: Union[Iterable[Model], Model],
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information: List[str] = None,
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user_id: Optional[int] = None,
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restricted: bool = False,
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) -> None:
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"""
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Informs the autoupdate system and the caching system about the creation or
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update of an element.
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The argument instances can be one instance or an iterable over instances.
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History creation is enabled.
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"""
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if information is None:
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information = []
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root_instances = set()
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if not isinstance(instances, Iterable):
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instances = (instances,)
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for instance in instances:
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try:
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root_instances.add(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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elements: Dict[str, Element] = {}
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for root_instance in root_instances:
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key = root_instance.get_collection_string() + str(root_instance.get_rest_pk())
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elements[key] = Element(
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id=root_instance.get_rest_pk(),
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collection_string=root_instance.get_collection_string(),
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full_data=root_instance.get_full_data(),
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information=information,
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restricted=restricted,
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user_id=user_id,
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)
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bundle = autoupdate_bundle.get(threading.get_ident())
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if bundle is not None:
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# Put all elements into the autoupdate_bundle.
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bundle.update(elements)
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else:
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# Send autoupdate directly
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handle_changed_elements(elements.values())
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def inform_deleted_data(
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deleted_elements: Iterable[Tuple[str, int]],
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information: List[str] = None,
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user_id: Optional[int] = None,
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restricted: bool = False,
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) -> None:
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"""
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Informs the autoupdate system and the caching system about the deletion of
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elements.
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History creation is enabled.
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"""
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if information is None:
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information = []
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elements: Dict[str, Element] = {}
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for deleted_element in deleted_elements:
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key = deleted_element[0] + str(deleted_element[1])
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elements[key] = Element(
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id=deleted_element[1],
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collection_string=deleted_element[0],
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full_data=None,
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information=information,
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restricted=restricted,
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user_id=user_id,
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)
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bundle = autoupdate_bundle.get(threading.get_ident())
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if bundle is not None:
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# Put all elements into the autoupdate_bundle.
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bundle.update(elements)
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else:
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# Send autoupdate directly
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handle_changed_elements(elements.values())
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def inform_changed_elements(changed_elements: Iterable[Element]) -> None:
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"""
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Informs the autoupdate system about some elements. This is used just to send
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some data to all users.
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If you want to save history information, user id or disable history you
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have to put information or flag inside the elements.
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"""
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elements = {}
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for changed_element in changed_elements:
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key = changed_element["collection_string"] + str(changed_element["id"])
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elements[key] = changed_element
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bundle = autoupdate_bundle.get(threading.get_ident())
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if bundle is not None:
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# Put all collection elements into the autoupdate_bundle.
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bundle.update(elements)
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else:
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# Send autoupdate directly
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handle_changed_elements(elements.values())
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"""
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Global container for autoupdate bundles
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"""
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autoupdate_bundle: Dict[int, Dict[str, Element]] = {}
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class AutoupdateBundleMiddleware:
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"""
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Middleware to handle autoupdate bundling.
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"""
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def __init__(self, get_response: Any) -> None:
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self.get_response = get_response
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# One-time configuration and initialization.
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def __call__(self, request: Any) -> Any:
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thread_id = threading.get_ident()
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autoupdate_bundle[thread_id] = {}
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response = self.get_response(request)
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bundle: Dict[str, Element] = autoupdate_bundle.pop(thread_id)
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handle_changed_elements(bundle.values())
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return response
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def handle_changed_elements(elements: Iterable[Element]) -> None:
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"""
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Helper function, that sends elements through a channel to the
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autoupdate system and updates the cache.
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Does nothing if elements is empty.
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"""
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async def update_cache(elements: Iterable[Element]) -> int:
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"""
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Async helper function to update the cache.
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Returns the change_id
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"""
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cache_elements: Dict[str, Optional[Dict[str, Any]]] = {}
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for element in elements:
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element_id = get_element_id(element["collection_string"], element["id"])
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cache_elements[element_id] = element["full_data"]
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return await element_cache.change_elements(cache_elements)
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async def async_handle_collection_elements(elements: Iterable[Element]) -> None:
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"""
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Async helper function to update cache and send autoupdate.
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"""
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# Update cache
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change_id = await update_cache(elements)
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# Send autoupdate
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channel_layer = get_channel_layer()
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await channel_layer.group_send(
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"autoupdate", {"type": "send_data", "change_id": change_id}
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)
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projector_data = await get_projector_data()
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# Send projector
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channel_layer = get_channel_layer()
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await channel_layer.group_send(
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"projector", {"type": "projector_changed", "data": projector_data}
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)
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if elements:
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for element in elements:
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if element.get("reload"):
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model = get_model_from_collection_string(element["collection_string"])
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try:
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instance = model.objects.get(pk=element["id"])
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except model.DoesNotExist:
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# The instance was deleted so we set full_data explicitly to None.
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element["full_data"] = None
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else:
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element["full_data"] = instance.get_full_data()
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# Save histroy here using sync code.
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save_history(elements)
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# Update cache and send autoupdate using async code.
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async_to_sync(async_handle_collection_elements)(elements)
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def save_history(elements: Iterable[Element]) -> Iterable:
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# TODO: Try to write Iterable[History] here
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"""
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Thin wrapper around the call of history saving manager method.
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This is separated to patch it during tests.
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"""
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from ..core.models import History
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return History.objects.add_elements(elements)
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