Change to standalone stoken objects (+ small optimisation).

Makes it possible to now generate Stokens as we need so we can add them to
non-revision objects, for example, membership changes.

We also slightly improved how we filter by revs.

django_etesync/models.py

@@ -18,6 +18,7 @@ from django.db import models
 from django.conf import settings
 from django.core.validators import RegexValidator
 from django.utils.functional import cached_property
+from django.utils.crypto import get_random_string
 
 
 Base64Url256BitlValidator = RegexValidator(regex=r'^[a-zA-Z0-9\-_]{42,43}$', message='Expected a base64url.')
@@ -55,7 +56,7 @@ class Collection(models.Model):
             # FIXME: what is the etag for None? Though if we use the revision for collection it should be shared anyway.
             return None
 
-        return last_revision.uid
+        return last_revision.stoken.uid
 
 
 class CollectionItem(models.Model):
@@ -77,7 +78,7 @@ class CollectionItem(models.Model):
 
     @property
     def stoken(self):
-        return self.content.uid
+        return self.content.stoken.uid
 
 
 def chunk_directory_path(instance, filename):
@@ -98,7 +99,17 @@ class CollectionItemChunk(models.Model):
         return self.uid
 
 
+def generate_stoken_uid():
+    return get_random_string(32, allowed_chars='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_')
+
+
+class Stoken(models.Model):
+    uid = models.CharField(db_index=True, unique=True, blank=False, null=False, default=generate_stoken_uid,
+                           max_length=43, validators=[Base64Url256BitlValidator])
+
+
 class CollectionItemRevision(models.Model):
+    stoken = models.OneToOneField(Stoken, on_delete=models.PROTECT)
     uid = models.CharField(db_index=True, unique=True, blank=False, null=False,
                            max_length=43, validators=[Base64Url256BitlValidator])
     item = models.ForeignKey(CollectionItem, related_name='revisions', on_delete=models.CASCADE)

django_etesync/serializers.py

@@ -38,7 +38,9 @@ def process_revisions_for_item(item, revision_data):
             chunk = models.CollectionItemChunk.objects.get(uid=uid)
             chunks_objs.append(chunk)
 
-    revision = models.CollectionItemRevision.objects.create(**revision_data, item=item)
+    stoken = models.Stoken.objects.create()
+
+    revision = models.CollectionItemRevision.objects.create(**revision_data, item=item, stoken=stoken)
     for chunk in chunks_objs:
         models.RevisionChunkRelation.objects.create(chunk=chunk, revision=revision)
     return revision

django_etesync/views.py

@@ -35,7 +35,15 @@ import nacl.secret
 import nacl.hash
 
 from . import app_settings, permissions
-from .models import Collection, CollectionItem, CollectionItemRevision, CollectionMember, CollectionInvitation, UserInfo
+from .models import (
+        Collection,
+        CollectionItem,
+        CollectionItemRevision,
+        CollectionMember,
+        CollectionInvitation,
+        Stoken,
+        UserInfo,
+    )
 from .serializers import (
         b64encode,
         AuthenticationSignupSerializer,
@@ -94,18 +102,18 @@ class BaseViewSet(viewsets.ModelViewSet):
         user = self.request.user
         return queryset.filter(members__user=user)
 
-    def get_cstoken_rev(self, request):
+    def get_cstoken_obj(self, request):
         cstoken = request.GET.get('cstoken', None)
 
         if cstoken is not None:
-            return get_object_or_404(CollectionItemRevision.objects.all(), uid=cstoken)
+            return get_object_or_404(Stoken.objects.all(), uid=cstoken)
 
         return None
 
     def filter_by_cstoken(self, request, queryset):
         cstoken_id_field = self.cstoken_id_field + '__id'
 
-        cstoken_rev = self.get_cstoken_rev(request)
+        cstoken_rev = self.get_cstoken_obj(request)
         if cstoken_rev is not None:
             filter_by = {cstoken_id_field + '__gt': cstoken_rev.id}
             queryset = queryset.filter(**filter_by)
@@ -116,7 +124,7 @@ class BaseViewSet(viewsets.ModelViewSet):
         cstoken_id_field = self.cstoken_id_field + '__id'
 
         new_cstoken_id = queryset.aggregate(cstoken_id=Max(cstoken_id_field))['cstoken_id']
-        new_cstoken = new_cstoken_id and CollectionItemRevision.objects.get(id=new_cstoken_id).uid
+        new_cstoken = new_cstoken_id and Stoken.objects.get(id=new_cstoken_id).uid
 
         return queryset, new_cstoken
 
@@ -139,7 +147,7 @@ class CollectionViewSet(BaseViewSet):
     queryset = Collection.objects.all()
     serializer_class = CollectionSerializer
     lookup_field = 'uid'
-    cstoken_id_field = 'items__revisions'
+    cstoken_id_field = 'items__revisions__stoken'
 
     def get_queryset(self, queryset=None):
         if queryset is None:
@@ -199,7 +207,7 @@ class CollectionItemViewSet(BaseViewSet):
     queryset = CollectionItem.objects.all()
     serializer_class = CollectionItemSerializer
     lookup_field = 'uid'
-    cstoken_id_field = 'revisions'
+    cstoken_id_field = 'revisions__stoken'
 
     def get_queryset(self):
         collection_uid = self.kwargs['collection_uid']
@@ -290,8 +298,8 @@ class CollectionItemViewSet(BaseViewSet):
             queryset, cstoken_rev = self.filter_by_cstoken(request, queryset)
 
             uids, stokens = zip(*[(item['uid'], item.get('stoken')) for item in serializer.validated_data])
-            rev_ids = CollectionItemRevision.objects.filter(uid__in=stokens, current=True).values_list('id', flat=True)
-            queryset = queryset.filter(uid__in=uids).exclude(revisions__id__in=rev_ids)
+            revs = CollectionItemRevision.objects.filter(stoken__uid__in=stokens, current=True)
+            queryset = queryset.filter(uid__in=uids).exclude(revisions__in=revs)
 
             queryset, new_cstoken = self.get_queryset_cstoken(queryset)
             cstoken = cstoken_rev and cstoken_rev.uid