Merge pull request #147 from hydroserver2/33-cache-improvements

Added django simple history models, and added modified_since param

core/endpoints/datastream/utils.py

@@ -5,6 +5,7 @@
 from django.utils import timezone
 from uuid import UUID
 from typing import List, Optional
+from datetime import datetime
 from functools import reduce
 from core.models import Person, Datastream, ThingAssociation, Observation, ResultQualifier
 from core.endpoints.thing.utils import check_thing_by_id
@@ -60,6 +61,20 @@ def apply_datastream_auth_rules(
     return datastream_query, result_exists
 
 
+def apply_recent_datastream_filter(
+        datastream_query: QuerySet,
+        modified_since: datetime
+) -> QuerySet:
+
+    datastream_history_filter = Q(log__history_date__gt=modified_since)
+
+    datastream_query = datastream_query.filter(
+        datastream_history_filter
+    )
+
+    return datastream_query
+
+
 def query_datastreams(
         user: Optional[Person],
         check_result_exists: bool = False,
@@ -71,7 +86,8 @@ def query_datastreams(
         thing_ids: Optional[List[UUID]] = None,
         sensor_ids: Optional[List[UUID]] = None,
         data_source_ids: Optional[List[UUID]] = None,
-        observed_property_ids: Optional[List[UUID]] = None
+        observed_property_ids: Optional[List[UUID]] = None,
+        modified_since: Optional[datetime] = None
 ) -> (QuerySet, bool):
 
     datastream_query = Datastream.objects
@@ -95,6 +111,10 @@ def query_datastreams(
         'processing_level', 'unit', 'intended_time_spacing_units', 'time_aggregation_interval_units'
     )
 
+    if modified_since:
+        datastream_query = datastream_query.prefetch_related('log')
+        datastream_query = apply_recent_datastream_filter(datastream_query, modified_since)
+
     datastream_query, result_exists = apply_datastream_auth_rules(
         user=user,
         datastream_query=datastream_query,

core/endpoints/datastream/views.py

@@ -1,5 +1,7 @@
 from ninja import Path
 from uuid import UUID
+from typing import Optional
+from datetime import datetime
 from django.db import transaction, IntegrityError
 from django.http import StreamingHttpResponse
 from accounts.auth.jwt import JWTAuth
@@ -16,14 +18,14 @@
 
 
 @router.dm_list('', response=DatastreamGetResponse)
-def get_datastreams(request):
+def get_datastreams(request, modified_since: Optional[datetime] = None):
     """
     Get a list of Datastreams
 
     This endpoint returns a list of public Datastreams and Datastreams owned by the authenticated user if there is one.
     """
 
-    datastream_query, _ = query_datastreams(user=request.authenticated_user)
+    datastream_query, _ = query_datastreams(user=request.authenticated_user, modified_since=modified_since)
 
     return [
         build_datastream_response(datastream) for datastream in datastream_query.all()

core/endpoints/thing/utils.py

@@ -1,4 +1,5 @@
 import operator
+from datetime import datetime
 from ninja.errors import HttpError
 from django.db.models import Q, Count, Prefetch
 from django.db.models.query import QuerySet
@@ -54,6 +55,18 @@ def apply_thing_auth_rules(
     return thing_query, result_exists
 
 
+def apply_recent_thing_filter(
+        thing_query: QuerySet,
+        modified_since: datetime
+) -> QuerySet:
+
+    thing_query = thing_query.filter(
+       log__history_date__gt=modified_since
+    )
+
+    return thing_query
+
+
 def query_things(
         user: Optional[Person],
         check_result_exists: bool = False,
@@ -63,7 +76,8 @@ def query_things(
         ignore_privacy: bool = False,
         thing_ids: Optional[List[UUID]] = None,
         prefetch_photos: bool = False,
-        prefetch_datastreams: bool = False
+        prefetch_datastreams: bool = False,
+        modified_since: Optional[datetime] = None
 ) -> (QuerySet, bool):
 
     thing_query = Thing.objects
@@ -83,6 +97,10 @@ def query_things(
     if prefetch_datastreams:
         thing_query = thing_query.prefetch_related('datastreams')
 
+    if modified_since:
+        thing_query = thing_query.prefetch_related('log')
+        thing_query = apply_recent_thing_filter(thing_query, modified_since)
+
     thing_query, result_exists = apply_thing_auth_rules(
         user=user,
         thing_query=thing_query,

core/endpoints/thing/views.py

@@ -1,6 +1,7 @@
 from ninja import Path
-from typing import List
+from typing import List, Optional
 from uuid import UUID
+from datetime import datetime
 from django.db import transaction, IntegrityError
 from accounts.auth.jwt import JWTAuth
 from accounts.auth.basic import BasicAuth
@@ -24,14 +25,14 @@
 
 
 @router.dm_list('', response=ThingGetResponse)
-def get_things(request):
+def get_things(request, modified_since: Optional[datetime] = None):
     """
     Get a list of Things
 
     This endpoint returns a list of public Things and Things owned by the authenticated user if there is one.
     """
 
-    thing_query, _ = query_things(user=request.authenticated_user)
+    thing_query, _ = query_things(user=request.authenticated_user, modified_since=modified_since)
 
     return [
         build_thing_response(request.authenticated_user, thing) for thing in thing_query.all()