stash

backend/authentication/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 
 from authentication.models import ToolshedUser, KnownIdentity, FriendRequestOutgoing, FriendRequestIncoming, \
-    AccountPreference
+    AccountPreference, Group, GroupInvite, GroupInviteIncoming
 
 
 class ToolshedUserAdmin(admin.ModelAdmin):
@@ -29,8 +29,30 @@ class FriendRequestIncomingAdmin(admin.ModelAdmin):
     search_fields = ('secret', 'befriender_username', 'befriender_domain', 'befriendee_user', 'befriender_public_key')
 
 
+class GroupAdmin(admin.ModelAdmin):
+    list_display = ('name', 'domain', 'get_members')
+    search_fields = ('name', 'domain', 'members__username')
+
+    @admin.display(description='Members')
+    def get_members(self, obj):
+        return ', '.join(str(member) for member in obj.members.all())
+
+
+class GroupInviteAdmin(admin.ModelAdmin):
+    list_display = ('secret', 'group', 'invitee_username', 'invitee_domain')
+    search_fields = ('secret', 'group__name', 'invitee_username', 'invitee_domain')
+
+
+class GroupInviteIncomingAdmin(admin.ModelAdmin):
+    list_display = ('secret', 'group_name', 'group_domain', 'inviter_username', 'inviter_domain', 'invitee_user')
+    search_fields = ('secret', 'group_name', 'group_domain', 'inviter_username', 'inviter_domain', 'invitee_user')
+
+
 admin.site.register(ToolshedUser, ToolshedUserAdmin)
 admin.site.register(KnownIdentity, KnownIdentityAdmin)
 admin.site.register(FriendRequestOutgoing, FriendRequestOutgoingAdmin)
 admin.site.register(FriendRequestIncoming, FriendRequestIncomingAdmin)
 admin.site.register(AccountPreference, AccountPreferenceAdmin)
+admin.site.register(Group, GroupAdmin)
+admin.site.register(GroupInvite, GroupInviteAdmin)
+admin.site.register(GroupInviteIncoming, GroupInviteIncomingAdmin)

backend/authentication/migrations/0005_group_groupinviteincoming_groupinvite_and_more.py

@@ -0,0 +1,56 @@
+# Generated by Django 4.2.2 on 2026-08-19 13:44
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('authentication', '0004_alter_accountpreference_id'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Group',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=255)),
+                ('domain', models.CharField(max_length=255)),
+                ('members', models.ManyToManyField(related_name='member_of_groups', to='authentication.knownidentity')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='GroupInviteIncoming',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('secret', models.CharField(max_length=255)),
+                ('group_name', models.CharField(max_length=255)),
+                ('group_domain', models.CharField(max_length=255)),
+                ('inviter_username', models.CharField(max_length=255)),
+                ('inviter_domain', models.CharField(max_length=255)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('invitee_user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='group_invites_incoming', to=settings.AUTH_USER_MODEL)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='GroupInvite',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('secret', models.CharField(max_length=255)),
+                ('invitee_username', models.CharField(max_length=255)),
+                ('invitee_domain', models.CharField(max_length=255)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='invites', to='authentication.group')),
+            ],
+        ),
+        migrations.AddIndex(
+            model_name='group',
+            index=models.Index(fields=['name', 'domain'], name='group_idx'),
+        ),
+        migrations.AlterUniqueTogether(
+            name='group',
+            unique_together={('name', 'domain')},
+        ),
+    ]

backend/authentication/models.py

@@ -144,3 +144,42 @@ class FriendRequestIncoming(models.Model):
     befriender_public_key = models.CharField(max_length=255)
     befriendee_user = models.ForeignKey(ToolshedUser, on_delete=models.CASCADE, related_name='friend_requests_incoming')
     created_at = models.DateTimeField(auto_now_add=True)
+
+
+class Group(models.Model):
+    name = models.CharField(max_length=255)
+    domain = models.CharField(max_length=255)
+    members = models.ManyToManyField(KnownIdentity, related_name='member_of_groups')
+
+    class Meta:
+        unique_together = ('name', 'domain')
+        indexes = [
+            models.Index(fields=['name', 'domain'], name='group_idx'),
+        ]
+
+    def __str__(self):
+        return f"#{self.name}@{self.domain}"
+
+    def is_member(self, identity):
+        return self.members.filter(pk=identity.pk).exists()
+
+
+class GroupInvite(models.Model):
+    """A pending invite tracked on the group's own home backend, checked when the invitee's
+    accept request arrives (see GroupInviteIncoming for the mirror record on the invitee's own
+    backend, and docs/design-in-progress/groups-mvp.md for the full invite/accept dance)."""
+    secret = models.CharField(max_length=255)
+    group = models.ForeignKey(Group, on_delete=models.CASCADE, related_name='invites')
+    invitee_username = models.CharField(max_length=255)
+    invitee_domain = models.CharField(max_length=255)
+    created_at = models.DateTimeField(auto_now_add=True)
+
+
+class GroupInviteIncoming(models.Model):
+    secret = models.CharField(max_length=255)
+    group_name = models.CharField(max_length=255)
+    group_domain = models.CharField(max_length=255)
+    inviter_username = models.CharField(max_length=255)
+    inviter_domain = models.CharField(max_length=255)
+    invitee_user = models.ForeignKey(ToolshedUser, on_delete=models.CASCADE, related_name='group_invites_incoming')
+    created_at = models.DateTimeField(auto_now_add=True)

backend/authentication/serializers.py

@@ -1,6 +1,6 @@
 from rest_framework import serializers
 
-from authentication.models import ToolshedUser
+from authentication.models import ToolshedUser, Group
 
 
 class OwnerSerializer(serializers.ReadOnlyField):
@@ -10,3 +10,12 @@ class OwnerSerializer(serializers.ReadOnlyField):
 
     def to_representation(self, value):
         return value.username + '@' + value.domain
+
+
+class GroupOwnerSerializer(serializers.ReadOnlyField):
+    class Meta:
+        model = Group
+        fields = ['name', 'domain']
+
+    def to_representation(self, value):
+        return f"#{value.name}@{value.domain}"

backend/authentication/signature_auth.py

@@ -16,6 +16,12 @@ def split_userhandle_or_throw(userhandle):
     return username, domain
 
 
+def split_grouphandle_or_throw(grouphandle):
+    if not grouphandle.startswith('#'):
+        raise ValueError('Group handle must be in the format #name@domain')
+    return split_userhandle_or_throw(grouphandle[1:])
+
+
 def verify_request(request, raw_request_body):
     authentication_header = request.META.get('HTTP_AUTHORIZATION')
 
@@ -74,6 +80,36 @@ def verify_incoming_friend_request(request, raw_request_body):
         return False
 
 
+def verify_incoming_group_invite(request, raw_request_body, handle_field, key_field):
+    """Self-certifying verifier for the two legs of the group invite/accept dance that land on a
+    backend which doesn't have the caller cached as a KnownIdentity yet (see
+    docs/design-in-progress/groups-mvp.md): the inviter delivering an invite to the invitee's own
+    backend (handle_field='inviter', key_field='inviter_key'), and the invitee accepting on the
+    group's home backend (handle_field='invitee', key_field='invitee_key'). Mirrors
+    verify_incoming_friend_request exactly, just with configurable field names."""
+    try:
+        username, domain, signed_data, signature_bytes_hex = verify_request(request, raw_request_body)
+    except ValueError:
+        return False
+    try:
+        claimed_handle = request.data[handle_field]
+        claimed_key = request.data[key_field]
+    except KeyError:
+        return False
+    if not claimed_handle or not claimed_key:
+        return False
+    if username + "@" + domain != claimed_handle:
+        return False
+    if len(claimed_key) != 64:
+        return False
+    verify_key = VerifyKey(bytes.fromhex(claimed_key))
+    try:
+        verify_key.verify(signed_data.encode('utf-8'), bytes.fromhex(signature_bytes_hex))
+        return True
+    except BadSignatureError:
+        return False
+
+
 def authenticate_request_against_known_identities(request, raw_request_body):
     try:
         username, domain, signed_data, signature_bytes_hex = verify_request(request, raw_request_body)

backend/authentication/tests/helpers.py

@@ -3,7 +3,7 @@ import json
 from django.test import TestCase, Client
 from nacl.encoding import HexEncoder
 
-from authentication.models import ToolshedUser, KnownIdentity
+from authentication.models import ToolshedUser, KnownIdentity, Group
 from hostadmin.models import Domain
 from nacl.signing import SigningKey
 
@@ -86,3 +86,9 @@ class UserTestMixin:
                                                                  domain=self.f['example_com'].name)
         self.f['ext_user1'] = DummyExternalUser('extuser1', 'external.org')
         self.f['ext_user2'] = DummyExternalUser('extuser2', 'external.org')
+
+
+class GroupTestMixin:
+    def prepare_groups(self):
+        self.f['group1'] = Group.objects.create(name='group1', domain=self.f['example_com'].name)
+        self.f['group1'].members.add(self.f['local_user1'].public_identity)

backend/backend/urls.py

@@ -35,6 +35,7 @@ urlpatterns = [
     path('auth/', include('authentication.api')),
     path('admin/', include('hostadmin.api')),
     path('api/', include('toolshed.api.friend')),
+    path('api/', include('toolshed.api.group')),
     path('api/', include('toolshed.api.inventory')),
     path('api/', include('toolshed.api.info')),
     path('api/', include('toolshed.api.files')),

backend/toolshed/admin.py

@@ -19,9 +19,9 @@ class ItemPropertyInline(admin.TabularInline):
 
 class InventoryItemAdmin(admin.ModelAdmin):
     list_display = ('name', 'description', 'category', 'availability_policy', 'owned_quantity', 'owner',
-                     'storage_location', 'get_tags', 'get_properties')
+                     'owner_group', 'storage_location', 'get_tags', 'get_properties')
     search_fields = ('name', 'description', 'category__name', 'availability_policy', 'owner__username',
-                      'storage_location__name', 'tags__name', 'itemproperty__property__name')
+                      'owner_group__name', 'storage_location__name', 'tags__name', 'itemproperty__property__name')
     inlines = (ItemTagInline, ItemPropertyInline)
 
     def get_queryset(self, request):

backend/toolshed/api/group.py

@@ -0,0 +1,165 @@
+import secrets
+
+from django.urls import path
+from rest_framework import status
+from rest_framework.decorators import api_view, authentication_classes, permission_classes
+from rest_framework.generics import get_object_or_404
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+from rest_framework.views import APIView
+from rest_framework.viewsets import ViewSetMixin
+
+from authentication.models import Group, GroupInvite, GroupInviteIncoming, KnownIdentity, ToolshedUser
+from authentication.signature_auth import SignatureAuthentication, SignatureAuthenticationLocal, \
+    authenticate_request_against_local_users, split_grouphandle_or_throw, split_userhandle_or_throw, \
+    verify_incoming_group_invite
+from toolshed.serializers import GroupSerializer, GroupInviteIncomingSerializer
+
+
+class Groups(APIView, ViewSetMixin):
+    authentication_classes = [SignatureAuthentication]
+    permission_classes = [IsAuthenticated]
+
+    def get(self, request, format=None):  # /api/groups/
+        groups = request.user.member_of_groups.all()
+        return Response(GroupSerializer(groups, many=True).data)
+
+    def post(self, request, format=None):  # /api/groups/
+        name = request.data.get('name')
+        if not name:
+            return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': 'name is required'})
+        if Group.objects.filter(name=name, domain=request.user.domain).exists():
+            return Response(status=status.HTTP_409_CONFLICT, data={'status': 'a group with this name already exists'})
+        group = Group.objects.create(name=name, domain=request.user.domain)
+        group.members.add(request.user)
+        return Response(status=status.HTTP_201_CREATED, data=GroupSerializer(group).data)
+
+
+class GroupDetail(APIView, ViewSetMixin):
+    authentication_classes = [SignatureAuthentication]
+    permission_classes = [IsAuthenticated]
+
+    def get(self, request, pk, format=None):  # /api/groups/<pk>/
+        group = get_object_or_404(Group, pk=pk)
+        if not group.is_member(request.user):
+            return Response(status=status.HTTP_404_NOT_FOUND)
+        return Response(GroupSerializer(group).data)
+
+
+@api_view(['DELETE'])
+@authentication_classes([SignatureAuthentication])
+@permission_classes([IsAuthenticated])
+def removeGroupMember(request, pk, identity_id, format=None):  # /api/groups/<pk>/members/<identity_id>/
+    group = get_object_or_404(Group, pk=pk)
+    if not group.is_member(request.user):
+        return Response(status=status.HTTP_404_NOT_FOUND)
+    member = get_object_or_404(group.members, pk=identity_id)
+    if group.members.count() <= 1:
+        return Response(status=status.HTTP_400_BAD_REQUEST,
+                        data={'status': "cannot remove the group's last member"})
+    group.members.remove(member)
+    return Response(status=status.HTTP_204_NO_CONTENT)
+
+
+@api_view(['POST'])
+@authentication_classes([SignatureAuthentication])
+@permission_classes([IsAuthenticated])
+def createGroupInvite(request, pk, format=None):  # /api/groups/<pk>/invites/
+    group = get_object_or_404(Group, pk=pk)
+    if not group.is_member(request.user):
+        return Response(status=status.HTTP_404_NOT_FOUND)
+    invitee = request.data.get('invitee')
+    if not invitee:
+        return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': 'invitee is required'})
+    try:
+        invitee_username, invitee_domain = split_userhandle_or_throw(invitee)
+    except ValueError:
+        return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': 'invalid invitee handle'})
+    if group.members.filter(username=invitee_username, domain=invitee_domain).exists():
+        return Response(status=status.HTTP_208_ALREADY_REPORTED, data={'status': 'already a member'})
+    secret = secrets.token_hex(64)
+    GroupInvite.objects.create(group=group, invitee_username=invitee_username, invitee_domain=invitee_domain,
+                                secret=secret)
+    return Response(status=status.HTTP_201_CREATED, data={'secret': secret, 'status': 'pending'})
+
+
+class GroupInvitesIncoming(APIView, ViewSetMixin):
+    """/api/groupinvites/ - the invitee's own view of their pending invites, and the delivery
+    endpoint an inviter's client posts to directly on the invitee's own home backend (see
+    docs/design-in-progress/groups-mvp.md's invite/accept dance)."""
+    def get(self, request, format=None):  # /api/groupinvites/ - only ever a local user checking their own invites
+        raw_request = request.body.decode('utf-8')
+        if not (user := authenticate_request_against_local_users(request, raw_request)):
+            return Response(status=status.HTTP_401_UNAUTHORIZED, data={'status': 'unauthorized'})
+        invites = user.group_invites_incoming.all()
+        return Response(GroupInviteIncomingSerializer(invites, many=True).data)
+
+    def post(self, request, format=None):  # /api/groupinvites/ - delivery, self-certified, caller isn't known here
+        raw_request = request.body.decode('utf-8')
+        for field in ('group', 'inviter', 'inviter_key', 'invitee', 'secret'):
+            if field not in request.data:
+                return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': f'missing {field}'})
+        if not verify_incoming_group_invite(request, raw_request, 'inviter', 'inviter_key'):
+            return Response(status=status.HTTP_401_UNAUTHORIZED, data={'status': 'unauthorized'})
+        try:
+            group_name, group_domain = split_grouphandle_or_throw(request.data['group'])
+            inviter_username, inviter_domain = split_userhandle_or_throw(request.data['inviter'])
+            invitee_username, invitee_domain = split_userhandle_or_throw(request.data['invitee'])
+        except ValueError:
+            return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': 'invalid handle'})
+        try:
+            invitee_user = ToolshedUser.objects.get(username=invitee_username, domain=invitee_domain)
+        except ToolshedUser.DoesNotExist:
+            return Response(status=status.HTTP_404_NOT_FOUND, data={'status': 'invitee is not local to this server'})
+        GroupInviteIncoming.objects.create(
+            group_name=group_name, group_domain=group_domain,
+            inviter_username=inviter_username, inviter_domain=inviter_domain,
+            invitee_user=invitee_user, secret=request.data['secret'])
+        return Response(status=status.HTTP_201_CREATED, data={'status': 'delivered'})
+
+
+@api_view(['DELETE'])
+@authentication_classes([SignatureAuthenticationLocal])
+@permission_classes([IsAuthenticated])
+def declineGroupInvite(request, pk, format=None):  # /api/groupinvites/<pk>/
+    get_object_or_404(request.user.group_invites_incoming, pk=pk).delete()
+    return Response(status=status.HTTP_204_NO_CONTENT)
+
+
+@api_view(['POST'])
+def acceptGroupInvite(request, format=None):  # /api/group_invites/accept/ - lands on the group's home backend
+    raw_request = request.body.decode('utf-8')
+    for field in ('group', 'invitee', 'invitee_key', 'secret'):
+        if field not in request.data:
+            return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': f'missing {field}'})
+    if not verify_incoming_group_invite(request, raw_request, 'invitee', 'invitee_key'):
+        return Response(status=status.HTTP_401_UNAUTHORIZED, data={'status': 'unauthorized'})
+    try:
+        group_name, group_domain = split_grouphandle_or_throw(request.data['group'])
+        invitee_username, invitee_domain = split_userhandle_or_throw(request.data['invitee'])
+    except ValueError:
+        return Response(status=status.HTTP_400_BAD_REQUEST, data={'status': 'invalid handle'})
+    try:
+        group = Group.objects.get(name=group_name, domain=group_domain)
+    except Group.DoesNotExist:
+        return Response(status=status.HTTP_404_NOT_FOUND, data={'status': 'no such group here'})
+    invite = GroupInvite.objects.filter(group=group, invitee_username=invitee_username,
+                                        invitee_domain=invitee_domain, secret=request.data['secret'])
+    if not invite.exists():
+        return Response(status=status.HTTP_404_NOT_FOUND, data={'status': 'no matching invite'})
+    identity, _ = KnownIdentity.objects.get_or_create(
+        username=invitee_username, domain=invitee_domain, public_key=request.data['invitee_key'])
+    group.members.add(identity)
+    invite.delete()
+    return Response(status=status.HTTP_201_CREATED, data={'status': 'accepted'})
+
+
+urlpatterns = [
+    path('groups/', Groups.as_view(), name='groups'),
+    path('groups/<int:pk>/', GroupDetail.as_view(), name='group_detail'),
+    path('groups/<int:pk>/members/<int:identity_id>/', removeGroupMember, name='remove_group_member'),
+    path('groups/<int:pk>/invites/', createGroupInvite, name='create_group_invite'),
+    path('groupinvites/', GroupInvitesIncoming.as_view(), name='group_invites_incoming'),
+    path('groupinvites/<int:pk>/', declineGroupInvite, name='decline_group_invite'),
+    path('group_invites/accept/', acceptGroupInvite, name='accept_group_invite'),
+]

backend/toolshed/api/inventory.py

@@ -2,10 +2,11 @@ from django.db import transaction
 from django.urls import path
 from rest_framework import routers, viewsets, status
 from rest_framework.decorators import authentication_classes, api_view, permission_classes, action
+from rest_framework.exceptions import NotFound, PermissionDenied
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
 
-from authentication.models import ToolshedUser, KnownIdentity
+from authentication.models import ToolshedUser, KnownIdentity, Group
 from authentication.signature_auth import SignatureAuthentication, split_userhandle_or_throw
 from files.models import File
 from toolshed.models import InventoryItem, StorageLocation, WorkflowInstance
@@ -36,21 +37,61 @@ class InventoryItemViewSet(viewsets.ModelViewSet):
     permission_classes = [IsAuthenticated]
 
     def get_queryset(self):
-        if type(self.request.user) == KnownIdentity and self.request.user.user.exists():
+        # A KnownIdentity acting purely as a group member (e.g. a remote member on a group
-            return InventoryItem.objects.filter(owner=self.request.user.user.get())
+        # hosted on this backend) never has a local ToolshedUser account here - group-owned
+        # items must stay reachable for such an identity, only personal ("owner=...") items
+        # require .user.exists().
+        if type(self.request.user) != KnownIdentity:
+            return InventoryItem.objects.none()
+        identity = self.request.user
+        group_items = InventoryItem.objects.filter(owner_group__in=identity.member_of_groups.all())
+        if self.action != 'list':
+            # retrieve/update/destroy: anything the caller may act on - their own items, or any
+            # group they're currently a member of. The narrower per-group listing below is only
+            # for the list action, so the main Inventory page stays scoped to personal items.
+            if identity.user.exists():
+                return InventoryItem.objects.filter(owner=identity.user.get()) | group_items
+            return group_items
+        group_id = self.request.query_params.get('group')
+        if group_id:
+            try:
+                group = Group.objects.get(pk=group_id)
+            except Group.DoesNotExist:
+                return InventoryItem.objects.none()
+            if not group.is_member(identity):
+                return InventoryItem.objects.none()
+            return InventoryItem.objects.filter(owner_group=group)
+        if identity.user.exists():
+            return InventoryItem.objects.filter(owner=identity.user.get())
         return InventoryItem.objects.none()
 
     def perform_create(self, serializer):
+        group_id = self.request.data.get('owner_group')
         with transaction.atomic():
-            serializer.save(owner=self.request.user.user.get()).clean()
+            if group_id:
+                try:
+                    group = Group.objects.get(pk=group_id)
+                except Group.DoesNotExist:
+                    raise NotFound('No such group')
+                if not group.is_member(self.request.user):
+                    raise PermissionDenied('Not a member of this group')
+                serializer.save(owner=None, owner_group=group).clean()
+            else:
+                serializer.save(owner=self.request.user.user.get()).clean()
+
+    @staticmethod
+    def _is_authorized(request, instance):
+        if instance.owner_id:
+            return request.user.user.filter(pk=instance.owner_id).exists()
+        return instance.owner_group.is_member(request.user)
 
     def perform_update(self, serializer):
         with transaction.atomic():
-            if serializer.instance.owner == self.request.user.user.get():
+            if self._is_authorized(self.request, serializer.instance):
                 serializer.save().clean()
 
     def perform_destroy(self, instance):
-        if instance.owner == self.request.user.user.get():
+        if self._is_authorized(self.request, instance):
             instance.delete()
 
 

backend/toolshed/migrations/0012_inventoryitem_owner_group_alter_inventoryitem_owner.py

@@ -0,0 +1,27 @@
+# Generated by Django 4.2.2 on 2026-08-19 13:44
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('authentication', '0005_group_groupinviteincoming_groupinvite_and_more'),
+        ('toolshed', '0011_workflowinstance_staged_files'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='inventoryitem',
+            name='owner_group',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='inventory_items', to='authentication.group'),
+        ),
+        migrations.AlterField(
+            model_name='inventoryitem',
+            name='owner',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='inventory_items', to=settings.AUTH_USER_MODEL),
+        ),
+    ]

backend/toolshed/models.py

@@ -3,7 +3,7 @@ from django.core.validators import MinValueValidator, MaxValueValidator
 from django_softdelete.models import SoftDeleteModel
 from rest_framework.exceptions import ValidationError
 
-from authentication.models import ToolshedUser, KnownIdentity
+from authentication.models import ToolshedUser, KnownIdentity, Group
 from files.models import File
 
 
@@ -97,7 +97,10 @@ class InventoryItem(SoftDeleteModel):
     category = models.ForeignKey(Category, on_delete=models.CASCADE, null=True, related_name='inventory_items')
     availability_policy = models.CharField(max_length=20, choices=AVAILABILITY_POLICY_CHOICES, default='private')
     owned_quantity = models.IntegerField(default=1, validators=[MinValueValidator(0)])
-    owner = models.ForeignKey(ToolshedUser, on_delete=models.CASCADE, related_name='inventory_items')
+    owner = models.ForeignKey(ToolshedUser, on_delete=models.CASCADE, null=True, blank=True,
+                              related_name='inventory_items')
+    owner_group = models.ForeignKey(Group, on_delete=models.CASCADE, null=True, blank=True,
+                                    related_name='inventory_items')
     created_at = models.DateTimeField(auto_now_add=True)
     tags = models.ManyToManyField(Tag, through='ItemTag', related_name='inventory_items')
     properties = models.ManyToManyField(Property, through='ItemProperty')
@@ -108,6 +111,8 @@ class InventoryItem(SoftDeleteModel):
     def clean(self):
         if (self.name is None or self.name == "") and self.files.count() == 0:
             raise ValidationError("Name or at least one file must be set")
+        if (self.owner is None) == (self.owner_group is None):
+            raise ValidationError("Exactly one of owner or owner_group must be set")
 
 
 class ItemProperty(models.Model):

backend/toolshed/serializers.py

@@ -1,6 +1,6 @@
 from rest_framework import serializers
-from authentication.models import KnownIdentity, ToolshedUser, FriendRequestIncoming
+from authentication.models import KnownIdentity, ToolshedUser, FriendRequestIncoming, Group, GroupInviteIncoming
-from authentication.serializers import OwnerSerializer
+from authentication.serializers import OwnerSerializer, GroupOwnerSerializer
 from files.models import File
 from files.serializers import FileSerializer
 from toolshed.models import Category, Property, ItemProperty, InventoryItem, Tag, StorageLocation, WorkflowInstance
@@ -68,6 +68,45 @@ class FriendRequestSerializer(serializers.ModelSerializer):
         return obj.befriender_username + '@' + obj.befriender_domain
 
 
+class GroupMemberSerializer(serializers.ModelSerializer):
+    username = serializers.SerializerMethodField()
+
+    class Meta:
+        model = KnownIdentity
+        fields = ['id', 'username', 'public_key']
+
+    def get_username(self, obj):
+        return obj.username + '@' + obj.domain
+
+
+class GroupSerializer(serializers.ModelSerializer):
+    handle = serializers.SerializerMethodField()
+    members = GroupMemberSerializer(many=True, read_only=True)
+
+    class Meta:
+        model = Group
+        fields = ['id', 'name', 'domain', 'handle', 'members']
+        read_only_fields = ['domain', 'handle', 'members']
+
+    def get_handle(self, obj):
+        return str(obj)
+
+
+class GroupInviteIncomingSerializer(serializers.ModelSerializer):
+    group = serializers.SerializerMethodField()
+    inviter = serializers.SerializerMethodField()
+
+    class Meta:
+        model = GroupInviteIncoming
+        fields = ['id', 'group', 'inviter', 'secret']
+
+    def get_group(self, obj):
+        return f"#{obj.group_name}@{obj.group_domain}"
+
+    def get_inviter(self, obj):
+        return obj.inviter_username + '@' + obj.inviter_domain
+
+
 class PropertySerializer(serializers.ModelSerializer):
     category = serializers.SerializerMethodField()
     handle = serializers.SerializerMethodField()
@@ -139,6 +178,7 @@ class ItemPropertySerializer(serializers.ModelSerializer):
 
 class InventoryItemSerializer(serializers.ModelSerializer):
     owner = OwnerSerializer(read_only=True)
+    owner_group = GroupOwnerSerializer(read_only=True)
     tags = serializers.SerializerMethodField()
     tags_input = serializers.ListField(child=serializers.CharField(), write_only=True, required=False)
     properties = ItemPropertySerializer(many=True, required=False, source='itemproperty_set')
@@ -147,8 +187,8 @@ class InventoryItemSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = InventoryItem
-        fields = ['id', 'name', 'description', 'owner', 'category', 'availability_policy', 'owned_quantity', 'owner',
+        fields = ['id', 'name', 'description', 'owner', 'owner_group', 'category', 'availability_policy',
-                  'tags', 'tags_input', 'properties', 'files', 'storage_location']
+                  'owned_quantity', 'tags', 'tags_input', 'properties', 'files', 'storage_location']
 
     def get_tags(self, obj):
         return [tag.name for tag in obj.tags.all()]

backend/toolshed/tests/test_group.py

@@ -0,0 +1,191 @@
+from django.test import Client
+
+from authentication.tests import SignatureAuthClient, UserTestMixin, GroupTestMixin, ToolshedTestCase, \
+    DummyExternalUser
+from authentication.models import Group, GroupInvite, GroupInviteIncoming, KnownIdentity
+
+client = SignatureAuthClient()
+
+
+class GroupModelTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
+    def setUp(self):
+        super().setUp()
+        self.prepare_users()
+        self.prepare_groups()
+
+    def test_group_str(self):
+        self.assertEqual(str(self.f['group1']), '#group1@' + self.f['example_com'].name)
+
+    def test_is_member(self):
+        self.assertTrue(self.f['group1'].is_member(self.f['local_user1'].public_identity))
+        self.assertFalse(self.f['group1'].is_member(self.f['local_user2'].public_identity))
+
+
+class GroupApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
+    def setUp(self):
+        super().setUp()
+        self.prepare_users()
+
+    def test_create_group(self):
+        reply = client.post('/api/groups/', self.f['local_user1'], {'name': 'workshop'})
+        self.assertEqual(reply.status_code, 201)
+        group = Group.objects.get(name='workshop')
+        self.assertEqual(group.domain, self.f['local_user1'].domain)
+        self.assertTrue(group.is_member(self.f['local_user1'].public_identity))
+
+    def test_create_group_duplicate_name(self):
+        client.post('/api/groups/', self.f['local_user1'], {'name': 'workshop'})
+        reply = client.post('/api/groups/', self.f['local_user1'], {'name': 'workshop'})
+        self.assertEqual(reply.status_code, 409)
+
+    def test_create_group_missing_name(self):
+        reply = client.post('/api/groups/', self.f['local_user1'], {})
+        self.assertEqual(reply.status_code, 400)
+
+    def test_list_groups(self):
+        self.prepare_groups()
+        reply = client.get('/api/groups/', self.f['local_user1'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(len(reply.json()), 1)
+        reply2 = client.get('/api/groups/', self.f['local_user2'])
+        self.assertEqual(reply2.status_code, 200)
+        self.assertEqual(len(reply2.json()), 0)
+
+    def test_group_detail_member(self):
+        self.prepare_groups()
+        reply = client.get('/api/groups/{}/'.format(self.f['group1'].id), self.f['local_user1'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(reply.json()['handle'], str(self.f['group1']))
+        self.assertEqual(len(reply.json()['members']), 1)
+
+    def test_group_detail_non_member(self):
+        self.prepare_groups()
+        reply = client.get('/api/groups/{}/'.format(self.f['group1'].id), self.f['local_user2'])
+        self.assertEqual(reply.status_code, 404)
+
+    def test_remove_member(self):
+        self.prepare_groups()
+        self.f['group1'].members.add(self.f['local_user2'].public_identity)
+        reply = client.delete('/api/groups/{}/members/{}/'.format(
+            self.f['group1'].id, self.f['local_user2'].public_identity.id), self.f['local_user1'])
+        self.assertEqual(reply.status_code, 204)
+        self.assertEqual(self.f['group1'].members.count(), 1)
+
+    def test_remove_last_member_blocked(self):
+        self.prepare_groups()
+        reply = client.delete('/api/groups/{}/members/{}/'.format(
+            self.f['group1'].id, self.f['local_user1'].public_identity.id), self.f['local_user1'])
+        self.assertEqual(reply.status_code, 400)
+        self.assertEqual(self.f['group1'].members.count(), 1)
+
+    def test_remove_member_non_member_denied(self):
+        self.prepare_groups()
+        self.f['group1'].members.add(self.f['local_user2'].public_identity)
+        reply = client.delete('/api/groups/{}/members/{}/'.format(
+            self.f['group1'].id, self.f['local_user1'].public_identity.id), self.f['ext_user1'])
+        self.assertEqual(reply.status_code, 404)
+        self.assertEqual(self.f['group1'].members.count(), 2)
+
+
+class GroupInviteApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
+    def setUp(self):
+        super().setUp()
+        self.prepare_users()
+        self.prepare_groups()
+
+    def test_invite_local_member_full_flow(self):
+        group = self.f['group1']
+        inviter = self.f['local_user1']
+        invitee = self.f['local_user2']
+
+        reply1 = client.post('/api/groups/{}/invites/'.format(group.id), inviter, {'invitee': str(invitee)})
+        self.assertEqual(reply1.status_code, 201)
+        secret = reply1.json()['secret']
+        self.assertEqual(GroupInvite.objects.count(), 1)
+
+        reply2 = client.post('/api/groupinvites/', inviter, {
+            'group': str(group), 'inviter': str(inviter), 'inviter_key': inviter.public_key(),
+            'invitee': str(invitee), 'secret': secret
+        })
+        self.assertEqual(reply2.status_code, 201)
+        incoming = GroupInviteIncoming.objects.get()
+        self.assertEqual(incoming.invitee_user, invitee)
+
+        reply3 = client.get('/api/groupinvites/', invitee)
+        self.assertEqual(reply3.status_code, 200)
+        self.assertEqual(len(reply3.json()), 1)
+        self.assertEqual(reply3.json()[0]['group'], str(group))
+        self.assertEqual(reply3.json()[0]['inviter'], str(inviter))
+
+        reply4 = client.post('/api/group_invites/accept/', invitee, {
+            'group': str(group), 'invitee': str(invitee), 'invitee_key': invitee.public_key(), 'secret': secret
+        })
+        self.assertEqual(reply4.status_code, 201)
+        self.assertTrue(group.is_member(invitee.public_identity))
+        self.assertEqual(GroupInvite.objects.count(), 0)
+
+        reply5 = client.delete('/api/groupinvites/{}/'.format(incoming.id), invitee)
+        self.assertEqual(reply5.status_code, 204)
+        self.assertEqual(GroupInviteIncoming.objects.count(), 0)
+
+    def test_invite_non_member_denied(self):
+        group = self.f['group1']
+        reply = client.post('/api/groups/{}/invites/'.format(group.id), self.f['local_user2'],
+                            {'invitee': str(self.f['ext_user1'])})
+        self.assertEqual(reply.status_code, 404)
+        self.assertEqual(GroupInvite.objects.count(), 0)
+
+    def test_invite_already_member(self):
+        group = self.f['group1']
+        group.members.add(self.f['local_user2'].public_identity)
+        reply = client.post('/api/groups/{}/invites/'.format(group.id), self.f['local_user1'],
+                            {'invitee': str(self.f['local_user2'])})
+        self.assertEqual(reply.status_code, 208)
+
+    def test_decline_invite(self):
+        invite = GroupInviteIncoming.objects.create(
+            group_name=self.f['group1'].name, group_domain=self.f['group1'].domain,
+            inviter_username=self.f['local_user1'].username, inviter_domain=self.f['local_user1'].domain,
+            invitee_user=self.f['local_user2'], secret='some-secret')
+        reply = client.delete('/api/groupinvites/{}/'.format(invite.id), self.f['local_user2'])
+        self.assertEqual(reply.status_code, 204)
+        self.assertEqual(GroupInviteIncoming.objects.count(), 0)
+
+    def test_accept_wrong_secret(self):
+        group = self.f['group1']
+        inviter = self.f['local_user1']
+        invitee = self.f['local_user2']
+        client.post('/api/groups/{}/invites/'.format(group.id), inviter, {'invitee': str(invitee)})
+        reply = client.post('/api/group_invites/accept/', invitee, {
+            'group': str(group), 'invitee': str(invitee), 'invitee_key': invitee.public_key(),
+            'secret': 'not-the-right-secret'
+        })
+        self.assertEqual(reply.status_code, 404)
+        self.assertFalse(group.is_member(invitee.public_identity))
+
+    def test_accept_remote_member(self):
+        group = self.f['group1']
+        inviter = self.f['local_user1']
+        invitee = DummyExternalUser('newmember', 'remote.example', known=False)
+        reply1 = client.post('/api/groups/{}/invites/'.format(group.id), inviter, {'invitee': str(invitee)})
+        secret = reply1.json()['secret']
+
+        reply = client.post('/api/group_invites/accept/', invitee, {
+            'group': str(group), 'invitee': str(invitee), 'invitee_key': invitee.public_key(), 'secret': secret
+        })
+        self.assertEqual(reply.status_code, 201)
+        identity = KnownIdentity.objects.get(username='newmember', domain='remote.example')
+        self.assertTrue(group.is_member(identity))
+
+    def test_accept_bad_signature(self):
+        group = self.f['group1']
+        inviter = self.f['local_user1']
+        invitee = self.f['local_user2']
+        reply1 = client.post('/api/groups/{}/invites/'.format(group.id), inviter, {'invitee': str(invitee)})
+        secret = reply1.json()['secret']
+        bad_signature_client = SignatureAuthClient(bad_signature=True)
+        reply = bad_signature_client.post('/api/group_invites/accept/', invitee, {
+            'group': str(group), 'invitee': str(invitee), 'invitee_key': invitee.public_key(), 'secret': secret
+        })
+        self.assertEqual(reply.status_code, 401)
+        self.assertFalse(group.is_member(invitee.public_identity))

backend/toolshed/tests/test_inventory.py

@@ -1,4 +1,4 @@
-from authentication.tests import SignatureAuthClient, UserTestMixin, ToolshedTestCase
+from authentication.tests import SignatureAuthClient, UserTestMixin, GroupTestMixin, ToolshedTestCase
 from files.tests import FilesTestMixin
 from toolshed.models import InventoryItem, Category
 from toolshed.tests import InventoryTestMixin
@@ -333,4 +333,87 @@ class TestInventoryItemWithFileApiTestCase(UserTestMixin, FilesTestMixin, Invent
             'properties': [{'name': 'prop1', 'value': 'value1'}, {'name': 'prop2', 'value': 'value2'}],
             'files': [{'data': self.f['encoded_content3']}]
         })
-        self.assertEqual(reply.status_code, 400)
+        self.assertEqual(reply.status_code, 400)
+
+
+class GroupOwnedInventoryApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
+    def setUp(self):
+        super().setUp()
+        self.prepare_users()
+        self.prepare_groups()
+        self.f['group1'].members.add(self.f['local_user2'].public_identity)
+
+    def create_group_item(self, name='drill'):
+        return client.post('/api/inventory_items/', self.f['local_user1'], {
+            'name': name, 'owned_quantity': 1, 'availability_policy': 'private',
+            'owner_group': self.f['group1'].id,
+        })
+
+    def test_create_group_owned_item(self):
+        reply = self.create_group_item()
+        self.assertEqual(reply.status_code, 201)
+        item = InventoryItem.objects.get(name='drill')
+        self.assertIsNone(item.owner)
+        self.assertEqual(item.owner_group, self.f['group1'])
+        self.assertEqual(reply.json()['owner_group'], str(self.f['group1']))
+        self.assertIsNone(reply.json()['owner'])
+
+    def test_create_group_owned_item_non_member_denied(self):
+        reply = client.post('/api/inventory_items/', self.f['ext_user1'], {
+            'name': 'drill', 'owned_quantity': 1, 'availability_policy': 'private',
+            'owner_group': self.f['group1'].id,
+        })
+        self.assertEqual(reply.status_code, 403)
+        self.assertEqual(InventoryItem.objects.count(), 0)
+
+    def test_other_member_can_edit(self):
+        item_id = self.create_group_item().json()['id']
+        reply = client.patch('/api/inventory_items/{}/'.format(item_id), self.f['local_user2'], {
+            'name': 'drill-renamed'
+        })
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(InventoryItem.objects.get(id=item_id).name, 'drill-renamed')
+
+    def test_other_member_can_delete(self):
+        item_id = self.create_group_item().json()['id']
+        reply = client.delete('/api/inventory_items/{}/'.format(item_id), self.f['local_user2'])
+        self.assertEqual(reply.status_code, 204)
+        self.assertEqual(InventoryItem.objects.filter(id=item_id).count(), 0)
+
+    def test_remote_member_without_local_account_can_edit(self):
+        # A remote member (no ToolshedUser row at all on this backend, only a KnownIdentity -
+        # see docs/design-in-progress/groups-mvp.md) must still be able to act on group-owned
+        # items here; it must not be treated as unauthorized just because .user.exists() is False.
+        self.f['group1'].members.add(self.f['ext_user1'].public_identity)
+        item_id = self.create_group_item().json()['id']
+        reply = client.get('/api/inventory_items/{}/'.format(item_id), self.f['ext_user1'])
+        self.assertEqual(reply.status_code, 200)
+        reply = client.patch('/api/inventory_items/{}/'.format(item_id), self.f['ext_user1'], {
+            'name': 'drill-renamed-by-remote-member'
+        })
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(InventoryItem.objects.get(id=item_id).name, 'drill-renamed-by-remote-member')
+
+    def test_non_member_cannot_see_or_edit(self):
+        item_id = self.create_group_item().json()['id']
+        reply = client.get('/api/inventory_items/{}/'.format(item_id), self.f['ext_user1'])
+        self.assertEqual(reply.status_code, 404)
+
+    def test_group_items_excluded_from_personal_list(self):
+        self.create_group_item()
+        reply = client.get('/api/inventory_items/', self.f['local_user1'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(len(reply.json()), 0)
+
+    def test_group_items_listed_by_group_query_param(self):
+        self.create_group_item()
+        reply = client.get('/api/inventory_items/?group={}'.format(self.f['group1'].id), self.f['local_user2'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(len(reply.json()), 1)
+        self.assertEqual(reply.json()[0]['name'], 'drill')
+
+    def test_group_items_not_listed_for_non_member_query_param(self):
+        self.create_group_item()
+        reply = client.get('/api/inventory_items/?group={}'.format(self.f['group1'].id), self.f['ext_user1'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(len(reply.json()), 0)

frontend/src/components/Sidebar.vue

@@ -33,6 +33,12 @@
                         <span class="align-middle">Friends</span>
                     </router-link>
                 </li>
+                <li class="sidebar-item">
+                    <router-link to="/groups" class="sidebar-link">
+                        <b-icon-people-fill class="bi-valign-middle"></b-icon-people-fill>
+                        <span class="align-middle">Groups</span>
+                    </router-link>
+                </li>
                 <li class="sidebar-item">
                     <router-link to="/files" class="sidebar-link">
                         <b-icon-folder class="bi-valign-middle"></b-icon-folder>

frontend/src/router.js

@@ -7,6 +7,9 @@ import store from '@/store';
 import Profile from '@/views/Profile.vue';
 import Settings from '@/views/Settings.vue';
 import Friends from '@/views/Friends.vue';
+import Groups from '@/views/Groups.vue';
+import GroupNew from '@/views/GroupNew.vue';
+import GroupDetail from '@/views/GroupDetail.vue';
 import Inventory from '@/views/Inventory.vue';
 import Search from '@/views/Search.vue';
 import InventoryDetail from '@/views/InventoryDetail.vue';
@@ -62,6 +65,19 @@ const routes = [{path: '/', component: Dashboard, meta: {requiresAuth: true}}, {
     path: '/friends',
     component: Friends,
     meta: {requiresAuth: true}
+}, {
+    path: '/groups',
+    component: Groups,
+    meta: {requiresAuth: true}
+}, {
+    path: '/groups/new',
+    component: GroupNew,
+    meta: {requiresAuth: true}
+}, {
+    path: '/groups/:id',
+    component: GroupDetail,
+    meta: {requiresAuth: true},
+    props: true
 }, {path: '/files', component: Files, meta: {requiresAuth: true}
 }, {path: '/workflows',
     component: Workflows,

frontend/src/store.js

@@ -72,6 +72,8 @@ export default createStore({
         remember: false,
         friends: [],
         friendProfiles: {},
+        groups: [],
+        groupInvites: [],
         item_map: {},
         home_servers: null,
         all_friends_servers: null,
@@ -104,6 +106,12 @@ export default createStore({
         setFriendProfiles(state, profiles) {
             state.friendProfiles = profiles;
         },
+        setGroups(state, groups) {
+            state.groups = groups;
+        },
+        setGroupInvites(state, invites) {
+            state.groupInvites = invites;
+        },
         setHomeServers(state, home_servers) {
             state.home_servers = home_servers;
         },
@@ -479,6 +487,75 @@ export default createStore({
             const servers = await dispatch('getHomeServers')
             return await servers.delete(getters.signAuth, '/api/friends/' + id + '/')
         },
+        // Groups are only ever hosted on the current user's own home backend for now (see
+        // docs/design-in-progress/groups-mvp.md) - a remote member's edit/delete rights on a
+        // group-owned item work regardless, but "My Groups" has no way to discover a group hosted
+        // elsewhere, so every group action below talks to getHomeServers rather than resolving a
+        // per-group domain.
+        async fetchGroups({commit, dispatch, getters}) {
+            const servers = await dispatch('getHomeServers')
+            const data = await servers.get(getters.signAuth, '/api/groups/')
+            commit('setGroups', data)
+            return data
+        },
+        async fetchGroup({dispatch, getters}, {id}) {
+            const servers = await dispatch('getHomeServers')
+            return await servers.get(getters.signAuth, '/api/groups/' + id + '/')
+        },
+        async createGroup({dispatch, getters}, {name}) {
+            const servers = await dispatch('getHomeServers')
+            return await servers.post(getters.signAuth, '/api/groups/', {name})
+        },
+        async removeGroupMember({dispatch, getters}, {groupId, identityId}) {
+            const servers = await dispatch('getHomeServers')
+            return await servers.delete(getters.signAuth, '/api/groups/' + groupId + '/members/' + identityId + '/')
+        },
+        async fetchGroupInvites({commit, dispatch, getters}) {
+            const servers = await dispatch('getHomeServers')
+            const data = await servers.get(getters.signAuth, '/api/groupinvites/')
+            commit('setGroupInvites', data)
+            return data
+        },
+        async inviteToGroup({state, dispatch, getters}, {groupId, groupHandle, invitee}) {
+            const home_servers = await dispatch('getHomeServers')
+            const home_reply = await home_servers.post(
+                getters.signAuth, '/api/groups/' + groupId + '/invites/', {invitee})
+            if (!home_reply.secret) {
+                return false
+            }
+            const invitee_servers = await dispatch('getFriendServers', {username: invitee})
+            await invitee_servers.post(getters.signAuth, '/api/groupinvites/', {
+                group: groupHandle,
+                inviter: state.user,
+                inviter_key: nacl.to_hex(state.keypair.signPk),
+                invitee,
+                secret: home_reply.secret
+            })
+            return true
+        },
+        async acceptGroupInvite({state, dispatch, getters}, invite) {
+            const group_domain = invite.group.split('@')[1]
+            const group_servers = await dispatch('getFriendServers', {username: 'x@' + group_domain})
+            await group_servers.post(getters.signAuth, '/api/group_invites/accept/', {
+                group: invite.group,
+                invitee: state.user,
+                invitee_key: nacl.to_hex(state.keypair.signPk),
+                secret: invite.secret
+            })
+            const home_servers = await dispatch('getHomeServers')
+            await home_servers.delete(getters.signAuth, '/api/groupinvites/' + invite.id + '/')
+            return true
+        },
+        async declineGroupInvite({dispatch, getters}, invite) {
+            const servers = await dispatch('getHomeServers')
+            return await servers.delete(getters.signAuth, '/api/groupinvites/' + invite.id + '/')
+        },
+        async fetchGroupInventoryItems({commit, dispatch, getters}, groupId) {
+            const servers = await dispatch('getHomeServers')
+            const items = await servers.get(getters.signAuth, '/api/inventory_items/?group=' + groupId)
+            commit('setInventoryItems', {url: '/group/' + groupId, items})
+            return items
+        },
         async fetchFiles({state, commit, dispatch, getters}) {
             if (state.last_load.files > Date.now() - 1000 * 60 * 60 * 24) {
                 return state.files
@@ -708,6 +785,7 @@ export default createStore({
         inventory_items(state) {
             return state.item_map['/'] || []
         },
+        groupInventoryItems: (state) => (groupId) => state.item_map['/group/' + groupId] || [],
         loaded_items(state) {
             return Object.entries(state.item_map).reduce((acc, [url, items]) => {
                 return acc.concat(items)

frontend/src/views/GroupDetail.vue

@@ -0,0 +1,207 @@
+<template>
+    <BaseLayout>
+        <main class="content">
+            <div class="container-fluid p-0">
+                <h1 class="h3 mb-3">{{ group ? group.handle : '' }}</h1>
+                <div class="row" v-if="group">
+                    <div class="col-12 col-xl-6">
+                        <div class="card">
+                            <div class="card-header">
+                                <h5 class="card-title">Members</h5>
+                            </div>
+                            <table class="table table-striped">
+                                <thead>
+                                <tr>
+                                    <th>Name</th>
+                                    <th style="width: 16em">
+                                        <a @click="refresh" class="align-middle">
+                                            <b-icon-arrow-clockwise></b-icon-arrow-clockwise>
+                                            Refresh
+                                        </a>
+                                        <a @click="show_invite = true" class="align-middle">
+                                            <b-icon-plus></b-icon-plus>
+                                            Add member
+                                        </a>
+                                    </th>
+                                </tr>
+                                </thead>
+                                <tbody>
+                                <tr v-if="show_invite">
+                                    <td>
+                                        <input type="text" class="form-control" placeholder="user@domain"
+                                               v-model="invitee">
+                                    </td>
+                                    <td>
+                                        <button class="btn btn-primary" @click="tryInvite">Invite</button>
+                                    </td>
+                                </tr>
+                                <tr v-for="member in group.members" :key="member.id">
+                                    <td>
+                                        <user-name-tag :user="member"/>
+                                    </td>
+                                    <td class="table-action">
+                                        <a href="#" class="align-middle" @click.prevent="tryRemoveMember(member)">
+                                            <b-icon-trash></b-icon-trash>
+                                            Remove
+                                        </a>
+                                    </td>
+                                </tr>
+                                </tbody>
+                            </table>
+                        </div>
+                    </div>
+                    <div class="col-12 col-xl-6">
+                        <div class="card">
+                            <div class="card-header">
+                                <h5 class="card-title">Group inventory</h5>
+                                <button v-if="layout === 'grid'" @click="layout = 'table'" class="btn">
+                                    <b-icon-list></b-icon-list>
+                                </button>
+                                <button v-else @click="layout = 'grid'" class="btn">
+                                    <b-icon-grid></b-icon-grid>
+                                </button>
+                            </div>
+                            <table class="table table-striped" v-if="layout === 'table'">
+                                <thead>
+                                <tr>
+                                    <th style="width:40%;">Name</th>
+                                    <th style="width:25%">Availability Policy</th>
+                                    <th class="d-none d-md-table-cell" style="width:25%">Amount</th>
+                                    <th>Actions</th>
+                                </tr>
+                                </thead>
+                                <tbody>
+                                <tr v-for="item in items" :key="item.id">
+                                    <td>
+                                        <router-link :to="`/inventory/${item.id}`">{{ item.name }}</router-link>
+                                    </td>
+                                    <td class="d-none d-md-table-cell">
+                                        <span class="badge bg-secondary text-white">{{ item.availability_policy }}</span>
+                                    </td>
+                                    <td class="d-none d-md-table-cell">{{ item.owned_quantity }}</td>
+                                    <td class="table-action">
+                                        <router-link :to="`/inventory/${item.id}/edit`">
+                                            <b-icon-pencil-square></b-icon-pencil-square>
+                                        </router-link>
+                                        <a :href="`/inventory/${item.id}/delete`" @click.prevent="tryDeleteItem(item)">
+                                            <b-icon-trash></b-icon-trash>
+                                        </a>
+                                    </td>
+                                </tr>
+                                </tbody>
+                            </table>
+                            <div class="card-body" v-else>
+                                <div class="row">
+                                    <div class="col-12 col-md-4 col-lg-3 col-xl-2" v-for="item in items" :key="item.id">
+                                        <div class="card">
+                                            <div class="card-body">
+                                                <h5 class="card-title mb-0">
+                                                    <router-link :to="`/inventory/${item.id}`">
+                                                        {{ item.name }}
+                                                    </router-link>
+                                                </h5>
+                                                <div class="card-text text-black-50">
+                                                    <span class="badge bg-secondary text-white">{{ item.availability_policy }}</span>
+                                                    <span class="float-right">{{ item.owned_quantity }}</span>
+                                                </div>
+                                                <div class="btn-group">
+                                                    <button class="btn btn-danger btn-sm" @click="tryDeleteItem(item)">
+                                                        Delete
+                                                    </button>
+                                                    <router-link :to="`/inventory/${item.id}/edit`"
+                                                                class="btn btn-primary btn-sm">Edit
+                                                    </router-link>
+                                                </div>
+                                            </div>
+                                        </div>
+                                    </div>
+                                </div>
+                            </div>
+                        </div>
+                        <div class="card">
+                            <button class="btn" @click="fetchItems">Refresh</button>
+                            <router-link :to="`/inventory/new?group=${id}`" class="btn btn-primary">Add</router-link>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </main>
+    </BaseLayout>
+</template>
+
+<script>
+import {mapActions, mapGetters, mapState} from "vuex";
+import * as BIcons from "bootstrap-icons-vue";
+import BaseLayout from "@/components/BaseLayout.vue";
+import UserNameTag from "@/components/UserNameTag.vue";
+
+export default {
+    name: 'GroupDetail',
+    components: {
+        BaseLayout,
+        UserNameTag,
+        ...BIcons
+    },
+    props: {
+        id: {
+            type: [String, Number],
+            required: true
+        }
+    },
+    data() {
+        return {
+            group: null,
+            layout: "grid",
+            show_invite: false,
+            invitee: ""
+        }
+    },
+    computed: {
+        ...mapState(['user']),
+        items() {
+            return this.groupInventoryItems(this.id)
+        },
+        ...mapGetters(['groupInventoryItems'])
+    },
+    methods: {
+        ...mapActions(['fetchGroup', 'removeGroupMember', 'inviteToGroup', 'fetchGroupInventoryItems',
+            'deleteInventoryItem']),
+        refresh() {
+            this.fetchGroup({id: this.id}).then((group) => {
+                this.group = group
+            })
+        },
+        fetchItems() {
+            this.fetchGroupInventoryItems(this.id)
+        },
+        tryInvite() {
+            this.inviteToGroup({groupId: this.id, groupHandle: this.group.handle, invitee: this.invitee})
+                .then((ok) => {
+                    if (ok) {
+                        this.show_invite = false
+                        this.invitee = ""
+                    }
+                }).catch(() => {
+            })
+        },
+        tryRemoveMember(member) {
+            this.removeGroupMember({groupId: this.id, identityId: member.id}).then(() => {
+                this.refresh()
+            }).catch(() => {
+            })
+        },
+        tryDeleteItem(item) {
+            this.deleteInventoryItem(item).then(() => {
+                this.fetchItems()
+            })
+        }
+    },
+    mounted() {
+        this.refresh()
+        this.fetchItems()
+    }
+}
+</script>
+
+<style scoped>
+</style>

frontend/src/views/GroupNew.vue

@@ -0,0 +1,52 @@
+<template>
+    <BaseLayout>
+        <main class="content">
+            <div class="container-fluid p-0">
+                <h1 class="h3 mb-3">New group</h1>
+                <div class="row">
+                    <div class="col-12 col-xl-6">
+                        <div class="card">
+                            <div class="card-body">
+                                <div class="mb-3">
+                                    <label class="form-label">Name</label>
+                                    <input type="text" class="form-control" v-model="name">
+                                </div>
+                                <button type="submit" class="btn btn-primary" style="width: 100%"
+                                        @click="tryCreateGroup">Create</button>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </main>
+    </BaseLayout>
+</template>
+
+<script>
+import {mapActions} from "vuex";
+import BaseLayout from "@/components/BaseLayout.vue";
+
+export default {
+    name: 'GroupNew',
+    components: {
+        BaseLayout
+    },
+    data() {
+        return {
+            name: ""
+        }
+    },
+    methods: {
+        ...mapActions(['createGroup']),
+        tryCreateGroup() {
+            this.createGroup({name: this.name}).then((group) => {
+                this.$router.push(`/groups/${group.id}`)
+            }).catch(() => {
+            })
+        }
+    }
+}
+</script>
+
+<style scoped>
+</style>

frontend/src/views/Groups.vue

@@ -0,0 +1,122 @@
+<template>
+    <BaseLayout>
+        <main class="content">
+            <div class="container-fluid p-0">
+                <h1 class="h3 mb-3">Groups</h1>
+                <div class="row">
+                    <div class="col-12 col-xl-6">
+                        <div class="card">
+                            <div class="card-header">
+                                <h5 class="card-title">My Groups</h5>
+                            </div>
+                            <table class="table table-striped">
+                                <thead>
+                                <tr>
+                                    <th>Name</th>
+                                    <th class="d-none d-md-table-cell" style="width:25%">Members</th>
+                                    <th style="width: 16em">
+                                        <a @click="fetchGroups" class="align-middle">
+                                            <b-icon-arrow-clockwise></b-icon-arrow-clockwise>
+                                            Refresh
+                                        </a>
+                                        <router-link to="/groups/new" class="align-middle">
+                                            <b-icon-plus></b-icon-plus>
+                                            New group
+                                        </router-link>
+                                    </th>
+                                </tr>
+                                </thead>
+                                <tbody>
+                                <tr v-for="group in groups" :key="group.id">
+                                    <td>
+                                        <router-link :to="`/groups/${group.id}`">{{ group.handle }}</router-link>
+                                    </td>
+                                    <td class="d-none d-md-table-cell">{{ group.members.length }}</td>
+                                    <td class="table-action"></td>
+                                </tr>
+                                </tbody>
+                            </table>
+                        </div>
+                    </div>
+                    <div class="col-12 col-xl-6">
+                        <div class="card">
+                            <div class="card-header">
+                                <h5 class="card-title">Open group invites</h5>
+                            </div>
+                            <table class="table table-striped">
+                                <thead>
+                                <tr>
+                                    <th>Group</th>
+                                    <th class="d-none d-md-table-cell" style="width:25%">Invited by</th>
+                                    <th style="width: 16em">
+                                        <a @click="fetchGroupInvites" class="align-middle">
+                                            <b-icon-arrow-clockwise></b-icon-arrow-clockwise>
+                                            Refresh
+                                        </a>
+                                    </th>
+                                </tr>
+                                </thead>
+                                <tbody>
+                                <tr v-for="invite in groupInvites" :key="invite.id">
+                                    <td>{{ invite.group }}</td>
+                                    <td class="d-none d-md-table-cell">{{ invite.inviter }}</td>
+                                    <td class="table-action">
+                                        <button class="btn btn-sm btn-success" @click="tryAcceptInvite(invite)">
+                                            <b-icon-check></b-icon-check>
+                                            Accept
+                                        </button> &nbsp;
+                                        <button class="btn btn-sm btn-danger" @click="tryDeclineInvite(invite)">
+                                            <b-icon-x></b-icon-x>
+                                            Decline
+                                        </button>
+                                    </td>
+                                </tr>
+                                </tbody>
+                            </table>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </main>
+    </BaseLayout>
+</template>
+
+<script>
+import {mapActions, mapState} from "vuex";
+import * as BIcons from "bootstrap-icons-vue";
+import BaseLayout from "@/components/BaseLayout.vue";
+
+export default {
+    name: 'Groups',
+    components: {
+        BaseLayout,
+        ...BIcons
+    },
+    computed: {
+        ...mapState(['groups', 'groupInvites']),
+    },
+    methods: {
+        ...mapActions(['fetchGroups', 'fetchGroupInvites', 'acceptGroupInvite', 'declineGroupInvite']),
+        tryAcceptInvite(invite) {
+            this.acceptGroupInvite(invite).then(() => {
+                this.fetchGroupInvites()
+                this.fetchGroups()
+            }).catch(() => {
+            })
+        },
+        tryDeclineInvite(invite) {
+            this.declineGroupInvite(invite).then(() => {
+                this.fetchGroupInvites()
+            }).catch(() => {
+            })
+        }
+    },
+    mounted() {
+        this.fetchGroups()
+        this.fetchGroupInvites()
+    }
+}
+</script>
+
+<style scoped>
+</style>

frontend/src/views/InventoryEdit.vue

@@ -92,7 +92,7 @@ export default {
         }
     },
     computed: {
-        ...mapGetters(["inventory_items"]),
+        ...mapGetters(["loaded_items"]),
         ...mapState(["availability_policies", "storage_locations"]),
         item() {
             return {
@@ -104,14 +104,14 @@ export default {
                 image: "",
                 files: [],
                 storage_location: null,
-                ...this.inventory_items.find(item => item.id === parseInt(this.id))
+                ...this.loaded_items.find(item => item.id === parseInt(this.id))
             }
         }
     },
     methods: {
         ...mapActions(["fetchInventoryItems", "updateInventoryItem", "fetchInfo", "fetchStorageLocations"]),
         changeFiles(files) {
-            this.inventory_items.find(item => item.id === parseInt(this.id)).files = files
+            this.loaded_items.find(item => item.id === parseInt(this.id)).files = files
         },
     },
     async mounted() {

frontend/src/views/InventoryNew.vue

@@ -24,6 +24,15 @@
                                 <label for="property" class="form-label">Property</label>
                                 <property-field :value="item.properties"></property-field>
                             </div>
+                            <div class="mb-3">
+                                <label for="owner" class="form-label">Owner</label>
+                                <select class="form-select" id="owner" name="owner" v-model="item.owner_group">
+                                    <option :value="null">Myself</option>
+                                    <option v-for="group in groups" :value="group.id" :key="group.id">
+                                        {{ group.handle }}
+                                    </option>
+                                </select>
+                            </div>
                             <div class="mb-3">
                                 <label for="quantity" class="form-label">Quantity</label>
                                 <input type="number" class="form-control" id="quantity" name="quantity"
@@ -96,19 +105,24 @@ export default {
                 tags: [],
                 properties: [],
                 files: [],
-                storage_location: null
+                storage_location: null,
+                owner_group: null
             }
         }
     },
     methods: {
-        ...mapActions(['createInventoryItem', 'fetchInfo', 'fetchStorageLocations'])
+        ...mapActions(['createInventoryItem', 'fetchInfo', 'fetchStorageLocations', 'fetchGroups'])
     },
     computed: {
-        ...mapState(["availability_policies", "storage_locations"]),
+        ...mapState(["availability_policies", "storage_locations", "groups"]),
     },
     async mounted() {
         await this.fetchInfo();
         await this.fetchStorageLocations();
+        await this.fetchGroups();
+        if (this.$route.query.group) {
+            this.item.owner_group = parseInt(this.$route.query.group, 10)
+        }
     }
 }
 </script>