stash

backend/authentication/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 
 from authentication.models import ToolshedUser, KnownIdentity, FriendRequestOutgoing, FriendRequestIncoming, \
-    AccountPreference, Group, GroupInvite, GroupInviteIncoming
+    AccountPreference, Group, GroupInvite, GroupInviteIncoming, GroupMembership
 
 
 class ToolshedUserAdmin(admin.ModelAdmin):
@@ -48,6 +48,11 @@ class GroupInviteIncomingAdmin(admin.ModelAdmin):
     search_fields = ('secret', 'group_name', 'group_domain', 'inviter_username', 'inviter_domain', 'invitee_user')
 
 
+class GroupMembershipAdmin(admin.ModelAdmin):
+    list_display = ('user', 'group_name', 'group_domain', 'created_at')
+    search_fields = ('user__username', 'group_name', 'group_domain')
+
+
 admin.site.register(ToolshedUser, ToolshedUserAdmin)
 admin.site.register(KnownIdentity, KnownIdentityAdmin)
 admin.site.register(FriendRequestOutgoing, FriendRequestOutgoingAdmin)
@@ -56,3 +61,4 @@ admin.site.register(AccountPreference, AccountPreferenceAdmin)
 admin.site.register(Group, GroupAdmin)
 admin.site.register(GroupInvite, GroupInviteAdmin)
 admin.site.register(GroupInviteIncoming, GroupInviteIncomingAdmin)
+admin.site.register(GroupMembership, GroupMembershipAdmin)

backend/authentication/migrations/0006_groupmembership.py

@@ -0,0 +1,28 @@
+# Generated by Django 4.2.2 on 2026-08-26 16:25
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('authentication', '0005_group_groupinviteincoming_groupinvite_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='GroupMembership',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('group_name', models.CharField(max_length=255)),
+                ('group_domain', models.CharField(max_length=255)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='group_memberships', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'unique_together': {('user', 'group_name', 'group_domain')},
+            },
+        ),
+    ]

backend/authentication/models.py

@@ -180,3 +180,23 @@ class GroupInviteIncoming(models.Model):
     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)
+
+
+class GroupMembership(models.Model):
+    """A pointer kept on a member's own home backend, recording that the local user is a member
+    of a group that may be hosted here or on a remote domain (mirrors FriendRequestIncoming's
+    role: independently recorded on the member's own side, not just the group's authoritative
+    backend). Written once the invitee's accept request against the group's home backend has
+    succeeded (see GroupInvitesIncomingAccept), analogous to how a friendship is independently
+    recorded on both sides via KnownIdentity.friends rather than only on one. See
+    docs/design-in-progress/groups-mvp.md's 'Known limitation'."""
+    user = models.ForeignKey(ToolshedUser, on_delete=models.CASCADE, related_name='group_memberships')
+    group_name = models.CharField(max_length=255)
+    group_domain = models.CharField(max_length=255)
+    created_at = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        unique_together = ('user', 'group_name', 'group_domain')
+
+    def __str__(self):
+        return f"{self.user} MEMBER_OF #{self.group_name}@{self.group_domain}"

backend/toolshed/api/group.py

@@ -9,11 +9,12 @@ 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.models import Group, GroupInvite, GroupInviteIncoming, GroupMembership, 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
+from toolshed.serializers import GroupSerializer, GroupInviteIncomingSerializer, GroupMembershipSerializer
 
 
 class Groups(APIView, ViewSetMixin):
@@ -126,6 +127,34 @@ def declineGroupInvite(request, pk, format=None):  # /api/groupinvites/<pk>/
     return Response(status=status.HTTP_204_NO_CONTENT)
 
 
+@api_view(['POST'])
+@authentication_classes([SignatureAuthenticationLocal])
+@permission_classes([IsAuthenticated])
+def recordGroupMembership(request, pk, format=None):  # /api/groupinvites/<pk>/accept/
+    """Local bookkeeping call on the invitee's own home backend, made by the client once its
+    accept request against the group's home backend (acceptGroupInvite) has succeeded. Turns the
+    now-obsolete GroupInviteIncoming into a durable GroupMembership pointer, so this backend
+    remembers which foreign groups its own user belongs to -- the same way FriendRequestIncoming
+    ends up recorded as a friend on both sides, not just the group's authoritative backend."""
+    invite = get_object_or_404(request.user.group_invites_incoming, pk=pk)
+    membership, _ = GroupMembership.objects.get_or_create(
+        user=request.user, group_name=invite.group_name, group_domain=invite.group_domain)
+    invite.delete()
+    return Response(status=status.HTTP_201_CREATED, data=GroupMembershipSerializer(membership).data)
+
+
+class GroupMemberships(APIView, ViewSetMixin):
+    """/api/groupmemberships/ - the personal index of every group (local or remote) this backend
+    has recorded the caller as belonging to, kept independently of the group's own membership
+    roster (see GroupMembership and recordGroupMembership)."""
+    authentication_classes = [SignatureAuthenticationLocal]
+    permission_classes = [IsAuthenticated]
+
+    def get(self, request, format=None):  # /api/groupmemberships/
+        memberships = request.user.group_memberships.all()
+        return Response(GroupMembershipSerializer(memberships, many=True).data)
+
+
 @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')
@@ -161,5 +190,7 @@ urlpatterns = [
     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('groupinvites/<int:pk>/accept/', recordGroupMembership, name='record_group_membership'),
     path('group_invites/accept/', acceptGroupInvite, name='accept_group_invite'),
+    path('groupmemberships/', GroupMemberships.as_view(), name='group_memberships'),
 ]

backend/toolshed/serializers.py

@@ -1,6 +1,7 @@
 from django.core.exceptions import ObjectDoesNotExist
 from rest_framework import serializers
-from authentication.models import KnownIdentity, ToolshedUser, FriendRequestIncoming, Group, GroupInviteIncoming
+from authentication.models import KnownIdentity, ToolshedUser, FriendRequestIncoming, Group, GroupInviteIncoming, \
+    GroupMembership
 from authentication.serializers import OwnerSerializer, GroupOwnerSerializer
 from files.models import File
 from files.serializers import FileSerializer
@@ -119,6 +120,17 @@ class GroupInviteIncomingSerializer(serializers.ModelSerializer):
         return obj.inviter_username + '@' + obj.inviter_domain
 
 
+class GroupMembershipSerializer(serializers.ModelSerializer):
+    handle = serializers.SerializerMethodField()
+
+    class Meta:
+        model = GroupMembership
+        fields = ['id', 'group_name', 'group_domain', 'handle', 'created_at']
+
+    def get_handle(self, obj):
+        return f"#{obj.group_name}@{obj.group_domain}"
+
+
 class PropertySerializer(serializers.ModelSerializer):
     category = serializers.SerializerMethodField()
     handle = serializers.SerializerMethodField()

backend/toolshed/tests/test_group.py

@@ -2,7 +2,7 @@ from django.test import Client
 
 from authentication.tests import SignatureAuthClient, UserTestMixin, GroupTestMixin, ToolshedTestCase, \
     DummyExternalUser
-from authentication.models import Group, GroupInvite, GroupInviteIncoming, KnownIdentity
+from authentication.models import Group, GroupInvite, GroupInviteIncoming, GroupMembership, KnownIdentity
 
 client = SignatureAuthClient()
 
@@ -124,9 +124,13 @@ class GroupInviteApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
         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)
+        reply5 = client.post('/api/groupinvites/{}/accept/'.format(incoming.id), invitee)
+        self.assertEqual(reply5.status_code, 201)
+        self.assertEqual(reply5.json()['handle'], str(group))
         self.assertEqual(GroupInviteIncoming.objects.count(), 0)
+        membership = GroupMembership.objects.get(user=invitee)
+        self.assertEqual(membership.group_name, group.name)
+        self.assertEqual(membership.group_domain, group.domain)
 
     def test_invite_non_member_denied(self):
         group = self.f['group1']
@@ -189,3 +193,69 @@ class GroupInviteApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
         })
         self.assertEqual(reply.status_code, 401)
         self.assertFalse(group.is_member(invitee.public_identity))
+
+
+class GroupMembershipApiTestCase(UserTestMixin, GroupTestMixin, ToolshedTestCase):
+    """Covers the pointer index kept on a member's own home backend (GroupMembership), which is
+    what lets that backend remember foreign group membership, analogous to how a friendship ends
+    up recorded on both sides rather than only on the group's authoritative backend."""
+
+    def setUp(self):
+        super().setUp()
+        self.prepare_users()
+        self.prepare_groups()
+
+    def test_record_membership_for_remote_group(self):
+        # local_user2's own home backend has no Group row at all for this group -- it's hosted
+        # entirely on another domain -- yet it should still remember the membership once the
+        # invitee's client confirms the accept against the group's home backend succeeded.
+        invitee = self.f['local_user2']
+        incoming = GroupInviteIncoming.objects.create(
+            group_name='remoteworkshop', group_domain='other.example',
+            inviter_username='someone', inviter_domain='other.example',
+            invitee_user=invitee, secret='some-secret')
+
+        reply = client.post('/api/groupinvites/{}/accept/'.format(incoming.id), invitee)
+
+        self.assertEqual(reply.status_code, 201)
+        self.assertEqual(reply.json()['handle'], '#remoteworkshop@other.example')
+        self.assertEqual(GroupInviteIncoming.objects.count(), 0)
+        membership = GroupMembership.objects.get(user=invitee)
+        self.assertEqual(membership.group_name, 'remoteworkshop')
+        self.assertEqual(membership.group_domain, 'other.example')
+
+    def test_record_membership_wrong_user_denied(self):
+        incoming = GroupInviteIncoming.objects.create(
+            group_name='remoteworkshop', group_domain='other.example',
+            inviter_username='someone', inviter_domain='other.example',
+            invitee_user=self.f['local_user2'], secret='some-secret')
+
+        reply = client.post('/api/groupinvites/{}/accept/'.format(incoming.id), self.f['local_user1'])
+
+        self.assertEqual(reply.status_code, 404)
+        self.assertEqual(GroupMembership.objects.count(), 0)
+        self.assertEqual(GroupInviteIncoming.objects.count(), 1)
+
+    def test_decline_does_not_record_membership(self):
+        incoming = GroupInviteIncoming.objects.create(
+            group_name='remoteworkshop', group_domain='other.example',
+            inviter_username='someone', inviter_domain='other.example',
+            invitee_user=self.f['local_user2'], secret='some-secret')
+
+        reply = client.delete('/api/groupinvites/{}/'.format(incoming.id), self.f['local_user2'])
+
+        self.assertEqual(reply.status_code, 204)
+        self.assertEqual(GroupMembership.objects.count(), 0)
+
+    def test_list_memberships(self):
+        GroupMembership.objects.create(
+            user=self.f['local_user1'], group_name='remoteworkshop', group_domain='other.example')
+
+        reply = client.get('/api/groupmemberships/', self.f['local_user1'])
+        self.assertEqual(reply.status_code, 200)
+        self.assertEqual(len(reply.json()), 1)
+        self.assertEqual(reply.json()[0]['handle'], '#remoteworkshop@other.example')
+
+        reply2 = client.get('/api/groupmemberships/', self.f['local_user2'])
+        self.assertEqual(reply2.status_code, 200)
+        self.assertEqual(len(reply2.json()), 0)

frontend/src/label-layouts.js

@@ -1,3 +1,5 @@
+import {encodeHandleForUrl} from "@/router";
+
 // A template's layout tree, content resolution, and selectability contract. See
 // docs/implementation.md#template-layout-tree.
 const GAP = {type: "empty", "min-width": "1mm", "min-height": "1mm"};
@@ -248,7 +250,7 @@ export const DERIVED_VARS = {
     // defaults to this origin but is editable, since any frontend can resolve any handle.
     itemUrl: {
         inputs: ["webdomain", "userHandle", "itemId"],
-        calc: (f) => `${f.webdomain}/i/${f.userHandle}/${f.itemId}`,
+        calc: (f) => `${f.webdomain}/i/${encodeHandleForUrl(f.userHandle)}/${f.itemId}`,
     },
     // Compact "owner handle + id" form (see docs/design-in-progress/items-labels.md) - meaningful
     // only where context already makes clear it's a Toolshed item, unlike itemUrl.
@@ -307,11 +309,6 @@ export function templateIsAvailable(t, fields) {
     return available;
 }
 
-// Resolves t's content leaves against fields into a tree for label.js's
-// drawLabel/drawFallbackLabel. Throws the same {message, short} shape as label.js's own
-// capacity errors (see docs/implementation.md#missing-data-is-a-templatecontent-error) when a
-// leaf isn't resolved yet, rather than returning null, so a caller's single catch around
-// drawLabel/drawFallbackLabel handles both without a separate isAvailable pre-check.
 export function templateContent(t, fields) {
     if (!templateIsAvailable(t, fields)) {
         const err = new Error("This layout needs more fields filled in before it can be drawn.");

frontend/src/router.js

@@ -51,18 +51,25 @@ function itemDetailRoute(handle, item_local_id) {
     return handle ? `/inventory/${encodeHandleForUrl(handle)}/${item_local_id}` : null;
 }
 
+export function ownerOverviewRoute(item) {
+    return item.owner_group ? `/groups/${encodeHandleForUrl(item.owner_group)}` : '/inventory';
+}
+
 const EXPANDED_ROUTE_BUILDERS = {
     item: ({owner_identity_id, item_local_id}) =>
         itemDetailRoute(store.getters.identityHandleById[owner_identity_id], item_local_id),
     group_item: ({owner_group_id, item_local_id}) =>
         itemDetailRoute(store.getters.groupHandleById[owner_group_id], item_local_id),
-    group: ({group_id}) => `/groups/${group_id}`,
+    group: ({group_id}) => {
+        const handle = store.getters.groupHandleById[group_id];
+        return handle ? `/groups/${encodeHandleForUrl(handle)}` : null;
+    },
     storage_location: ({storage_location_id}) => `/storage-locations/${storage_location_id}`,
     workflow: ({workflow_id}) => `/workflows/${workflow_id}`,
 };
 
 // Kinds whose route needs identityHandleById/groupHandleById (from state.idmap); ShortId.vue only waits on an idmap fetch for these.
-export const NEEDS_IDMAP = new Set(['item', 'group_item']);
+export const NEEDS_IDMAP = new Set(['item', 'group_item', 'group']);
 
 export function expandedRoute({kind, ...fields}) {
     const buildRoute = EXPANDED_ROUTE_BUILDERS[kind];
@@ -117,7 +124,7 @@ const routes = [{path: '/', component: Dashboard, meta: {requiresAuth: true}}, {
     component: GroupNew,
     meta: {requiresAuth: true}
 }, {
-    path: '/groups/:id',
+    path: '/groups/:handle',
     component: GroupDetail,
     meta: {requiresAuth: true},
     props: true

frontend/src/store.js

@@ -8,6 +8,11 @@ import {serializeWorkflowPayload, deserializeWorkflowPayload} from "@/workflows.
 //import sharedStatePlugin from "@/../extras/shared-state-plugin";
 //import persistentStatePlugin from "@/../extras/persistent-state-plugin";
 
+function splitGroupHandle(handle) {
+    const [name, domain] = handle.slice(1).split('@')
+    return {name, domain}
+}
+
 const defaultPreferenceDefinitions = [
     {
         key: 'ui.compact_mode',
@@ -74,6 +79,7 @@ export default createStore({
         friendProfiles: {},
         groups: [],
         groupInvites: [],
+        groupMemberships: [],
         idmap: {identities: [], groups: []},
         idmapLoaded: false,
         item_map: {},
@@ -114,6 +120,9 @@ export default createStore({
         setGroupInvites(state, invites) {
             state.groupInvites = invites;
         },
+        setGroupMemberships(state, memberships) {
+            state.groupMemberships = memberships;
+        },
         setIdMap(state, idmap) {
             state.idmap = idmap;
             state.idmapLoaded = true;
@@ -394,14 +403,22 @@ export default createStore({
             state.last_load.files = 0
             return reply
         },
+        // A group-owned item lives on its owning group's own backend, not necessarily the
+        // caller's home one (see the group actions below) - item.owner_group ("#name@domain")
+        // already carries that domain, so update/delete resolve it the same way rather than
+        // needing the caller to track it separately.
         async updateInventoryItem({state, dispatch, getters}, item) {
-            const servers = await dispatch('getHomeServers')
+            const servers = item.owner_group
+                ? await dispatch('getFriendServers', {username: 'x@' + splitGroupHandle(item.owner_group).domain})
+                : await dispatch('getHomeServers')
             const data = {availability_policy: 'friends', ...item}
             data.files = data.files.map(file => file.id)
             return await servers.patch(getters.signAuth, '/api/inventory_items/' + item.id + '/', data)
         },
         async deleteInventoryItem({state, dispatch, getters}, item) {
-            const servers = await dispatch('getHomeServers')
+            const servers = item.owner_group
+                ? await dispatch('getFriendServers', {username: 'x@' + splitGroupHandle(item.owner_group).domain})
+                : await dispatch('getHomeServers')
             const ret = await servers.delete(getters.signAuth, '/api/inventory_items/' + item.id + '/')
             dispatch('fetchInventoryItems')
             return ret
@@ -448,19 +465,21 @@ export default createStore({
                 return null;
             }
         },
-        // Group handles have no owner-handle GET route yet, so they resolve differently than
-        // personal handles here. See docs/implementation.md#fetch-item-by-handle-group-vs-personal-handles.
+        // A group handle resolves via fetchGroup (itself domain-routed, see below), so a group
+        // hosted elsewhere works exactly like one hosted on the caller's own backend - no idmap
+        // detour needed here. ServerSet.get() never checks response.ok, so a 404 (nonexistent or
+        // non-member group) surfaces as a JSON-parse rejection rather than resolving falsy - same
+        // try/catch shape as fetchForeignItem.
         async fetchItemByHandle({dispatch, getters}, {handle, id}) {
             if (handle.startsWith('#')) {
-                // idmap isn't guaranteed loaded on a direct/refreshed visit here; fetchIdMap is
-                // cheap and already called unconditionally by every other caller too.
-                await dispatch('fetchIdMap')
-                const groupId = getters.groupIdByHandle[handle]
-                if (groupId === undefined) {
-                    return null
+                try {
+                    const group = await dispatch('fetchGroup', {handle})
+                    const items = await dispatch('fetchGroupInventoryItems', {groupId: group.id, domain: group.domain})
+                    return items.find(item => item.id === parseInt(id)) || null
+                } catch (error) {
+                    console.error(`Failed to fetch group item ${id} for ${handle}:`, error);
+                    return null;
                 }
-                const items = await dispatch('fetchGroupInventoryItems', groupId)
-                return items.find(item => item.id === parseInt(id)) || null
             }
             return dispatch('fetchForeignItem', {owner: handle, id})
         },
@@ -511,9 +530,14 @@ 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), so every group action below uses getHomeServers
-        // rather than resolving a per-group domain.
+        // Listing/creating a group is inherently home-scoped - it's this backend's own view of
+        // "groups I host you in" - but every action below that acts on an *existing* group
+        // (found via its handle, e.g. from a GroupMembership pointer to a group hosted
+        // elsewhere - see GroupMembership/docs/design-in-progress/groups-mvp.md) resolves that
+        // group's own domain and talks to it directly, the same way requestFriend/
+        // fetchForeignItem resolve a friend's domain, rather than assuming home. A group hosted
+        // on the caller's own domain goes through exactly the same code path - there's nothing
+        // to special-case.
         async fetchGroups({commit, dispatch, getters}) {
             const servers = await dispatch('getHomeServers')
             const data = await servers.get(getters.signAuth, '/api/groups/')
@@ -526,16 +550,18 @@ export default createStore({
             commit('setIdMap', idmap)
             return idmap
         },
-        async fetchGroup({dispatch, getters}, {id}) {
-            const servers = await dispatch('getHomeServers')
-            return await servers.get(getters.signAuth, '/api/groups/' + id + '/')
+        // handle is "#name@domain".
+        async fetchGroup({dispatch, getters}, {handle}) {
+            const {name, domain} = splitGroupHandle(handle)
+            const servers = await dispatch('getFriendServers', {username: 'x@' + domain})
+            return await servers.get(getters.signAuth, `/api/groups/handle/${name}/${domain}/`)
         },
         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')
+        async removeGroupMember({dispatch, getters}, {groupId, domain, identityId}) {
+            const servers = await dispatch('getFriendServers', {username: 'x@' + domain})
             return await servers.delete(getters.signAuth, '/api/groups/' + groupId + '/members/' + identityId + '/')
         },
         async fetchGroupInvites({commit, dispatch, getters}) {
@@ -544,11 +570,17 @@ export default createStore({
             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(
+        async fetchGroupMemberships({commit, dispatch, getters}) {
+            const servers = await dispatch('getHomeServers')
+            const data = await servers.get(getters.signAuth, '/api/groupmemberships/')
+            commit('setGroupMemberships', data)
+            return data
+        },
+        async inviteToGroup({state, dispatch, getters}, {groupId, domain, groupHandle, invitee}) {
+            const group_servers = await dispatch('getFriendServers', {username: 'x@' + domain})
+            const group_reply = await group_servers.post(
                 getters.signAuth, '/api/groups/' + groupId + '/invites/', {invitee})
-            if (!home_reply.secret) {
+            if (!group_reply.secret) {
                 return false
             }
             const invitee_servers = await dispatch('getFriendServers', {username: invitee})
@@ -557,7 +589,7 @@ export default createStore({
                 inviter: state.user,
                 inviter_key: nacl.to_hex(state.keypair.signPk),
                 invitee,
-                secret: home_reply.secret
+                secret: group_reply.secret
             })
             return true
         },
@@ -571,17 +603,20 @@ export default createStore({
                 secret: invite.secret
             })
             const home_servers = await dispatch('getHomeServers')
-            await home_servers.delete(getters.signAuth, '/api/groupinvites/' + invite.id + '/')
+            await home_servers.post(getters.signAuth, '/api/groupinvites/' + invite.id + '/accept/', {})
             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')
+        async fetchGroupInventoryItems({commit, dispatch, getters}, {groupId, domain}) {
+            const servers = await dispatch('getFriendServers', {username: 'x@' + domain})
             const items = await servers.get(getters.signAuth, '/api/inventory_items/?group=' + groupId)
-            commit('setInventoryItems', {url: '/group/' + groupId, items})
+            // Namespaced by domain, not just groupId: that pk is only unique within its own
+            // backend's database, so two different domains could otherwise collide on the same
+            // item_map key.
+            commit('setInventoryItems', {url: '/group/' + domain + '/' + groupId, items})
             return items
         },
         async fetchFiles({state, commit, dispatch, getters}) {
@@ -813,7 +848,7 @@ export default createStore({
         inventory_items(state) {
             return state.item_map['/'] || []
         },
-        groupInventoryItems: (state) => (groupId) => state.item_map['/group/' + groupId] || [],
+        groupInventoryItems: (state) => (groupId, domain) => state.item_map['/group/' + domain + '/' + groupId] || [],
         identityIdByHandle(state) {
             return Object.fromEntries(state.idmap.identities.map(i => [i.username, i.id]))
         },

frontend/src/views/GroupDetail.vue

@@ -86,6 +86,9 @@
                                         <a :href="`${itemRoute(item)}/delete`" @click.prevent="tryDeleteItem(item)">
                                             <b-icon-trash></b-icon-trash>
                                         </a>
+                                        <router-link v-if="printLinkFor(item)" :to="printLinkFor(item)">
+                                            <b-icon-qr-code></b-icon-qr-code>
+                                        </router-link>
                                     </td>
                                 </tr>
                                 </tbody>
@@ -111,6 +114,10 @@
                                                     <router-link :to="`${itemRoute(item)}/edit`"
                                                                 class="btn btn-primary btn-sm">Edit
                                                     </router-link>
+                                                    <router-link v-if="printLinkFor(item)" :to="printLinkFor(item)"
+                                                                 class="btn btn-secondary btn-sm">
+                                                        <b-icon-qr-code></b-icon-qr-code>
+                                                    </router-link>
                                                 </div>
                                             </div>
                                         </div>
@@ -120,7 +127,9 @@
                         </div>
                         <div class="card">
                             <button class="btn" @click="fetchItems">Refresh</button>
-                            <router-link :to="`/inventory/new?group=${id}`" class="btn btn-primary">Add</router-link>
+                            <router-link v-if="isOwnDomain" :to="`/inventory/new?group=${group.id}`"
+                                         class="btn btn-primary">Add
+                            </router-link>
                         </div>
                     </div>
                 </div>
@@ -134,7 +143,7 @@ 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";
-import {encodeHandleForUrl} from "@/router";
+import {decodeHandleFromUrl, encodeHandleForUrl} from "@/router";
 
 export default {
     name: 'GroupDetail',
@@ -144,8 +153,8 @@ export default {
         ...BIcons
     },
     props: {
-        id: {
-            type: [String, Number],
+        handle: {
+            type: String,
             required: true
         }
     },
@@ -159,39 +168,55 @@ export default {
     },
     computed: {
         ...mapState(['user']),
+        decodedHandle() {
+            return decodeHandleFromUrl(this.handle)
+        },
         items() {
-            return this.groupInventoryItems(this.id)
+            return this.group ? this.groupInventoryItems(this.group.id, this.group.domain) : []
+        },
+        isOwnDomain() {
+            return this.group && this.group.domain === this.user.split('@')[1]
         },
         ...mapGetters(['groupInventoryItems'])
     },
     methods: {
         ...mapActions(['fetchGroup', 'removeGroupMember', 'inviteToGroup', 'fetchGroupInventoryItems',
             'deleteInventoryItem']),
+        // Loads by handle regardless of which backend actually hosts the group - see
+        // store.js's fetchGroup.
         refresh() {
-            this.fetchGroup({id: this.id}).then((group) => {
+            return this.fetchGroup({handle: this.decodedHandle}).then((group) => {
                 this.group = group
             })
         },
         fetchItems() {
-            this.fetchGroupInventoryItems(this.id)
+            if (this.group) {
+                this.fetchGroupInventoryItems({groupId: this.group.id, domain: this.group.domain})
+            }
         },
         itemRoute(item) {
             return `/inventory/${encodeHandleForUrl(this.group.handle)}/${item.id}`
         },
+        printLinkFor(item) {
+            return {path: '/print', query: {kind: 'item', userHandle: this.group.handle, item: item.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(() => {
+            this.inviteToGroup({
+                groupId: this.group.id, domain: this.group.domain, 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(() => {
+            this.removeGroupMember({groupId: this.group.id, domain: this.group.domain, identityId: member.id})
+                .then(() => {
+                    this.refresh()
+                }).catch(() => {
             })
         },
         tryDeleteItem(item) {
@@ -201,8 +226,7 @@ export default {
         }
     },
     mounted() {
-        this.refresh()
-        this.fetchItems()
+        this.refresh().then(() => this.fetchItems())
     }
 }
 </script>

frontend/src/views/GroupNew.vue

@@ -25,6 +25,7 @@
 <script>
 import {mapActions} from "vuex";
 import BaseLayout from "@/components/BaseLayout.vue";
+import {encodeHandleForUrl} from "@/router";
 
 export default {
     name: 'GroupNew',
@@ -40,7 +41,7 @@ export default {
         ...mapActions(['createGroup']),
         tryCreateGroup() {
             this.createGroup({name: this.name}).then((group) => {
-                this.$router.push(`/groups/${group.id}`)
+                this.$router.push(`/groups/${encodeHandleForUrl(group.handle)}`)
             }).catch(() => {
             })
         }

frontend/src/views/Groups.vue

@@ -7,7 +7,7 @@
                     <div class="col-12 col-xl-6">
                         <div class="card">
                             <div class="card-header">
-                                <h5 class="card-title">My Groups</h5>
+                                <h5 class="card-title">Groups</h5>
                             </div>
                             <table class="table table-striped">
                                 <thead>
@@ -15,7 +15,7 @@
                                     <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">
+                                        <a @click="refreshGroups" class="align-middle">
                                             <b-icon-arrow-clockwise></b-icon-arrow-clockwise>
                                             Refresh
                                         </a>
@@ -27,11 +27,16 @@
                                 </tr>
                                 </thead>
                                 <tbody>
-                                <tr v-for="group in groups" :key="group.id">
+                                <tr v-for="group in allGroups" :key="group.key">
                                     <td>
-                                        <router-link :to="`/groups/${group.id}`">{{ group.handle }}</router-link>
+                                        <router-link :to="`/groups/${encodeHandleForUrl(group.handle)}`">
+                                            {{ group.handle }}
+                                        </router-link>
                                     </td>
-                                    <td class="d-none d-md-table-cell">{{ group.members.length }}</td>
+                                    <!-- GroupDetail.vue loads a foreign group's roster live by handle (see
+                                         store.js's fetchGroup) - this list just avoids an N-request roundtrip
+                                         per row, so a member count is only free for a group hosted here. -->
+                                    <td class="d-none d-md-table-cell">{{ group.hosted ? group.memberCount : '—' }}</td>
                                     <td class="table-action"></td>
                                 </tr>
                                 </tbody>
@@ -85,6 +90,7 @@
 import {mapActions, mapState} from "vuex";
 import * as BIcons from "bootstrap-icons-vue";
 import BaseLayout from "@/components/BaseLayout.vue";
+import {encodeHandleForUrl} from "@/router";
 
 export default {
     name: 'Groups',
@@ -93,14 +99,31 @@ export default {
         ...BIcons
     },
     computed: {
-        ...mapState(['groups', 'groupInvites']),
+        ...mapState(['groups', 'groupInvites', 'groupMemberships']),
+        allGroups() {
+            const hosted = this.groups.map(group => ({
+                key: `hosted:${group.id}`, handle: group.handle, memberCount: group.members.length, hosted: true
+            }))
+            const hostedHandles = new Set(hosted.map(group => group.handle))
+            const foreign = this.groupMemberships
+                .filter(membership => !hostedHandles.has(membership.handle))
+                .map(membership => ({key: `foreign:${membership.id}`, handle: membership.handle, hosted: false}))
+            return [...hosted, ...foreign].sort((a, b) => a.handle.localeCompare(b.handle))
+        },
     },
     methods: {
-        ...mapActions(['fetchGroups', 'fetchGroupInvites', 'acceptGroupInvite', 'declineGroupInvite']),
+        encodeHandleForUrl,
+        ...mapActions(['fetchGroups', 'fetchGroupInvites', 'fetchGroupMemberships', 'acceptGroupInvite',
+            'declineGroupInvite']),
+        refreshGroups() {
+            this.fetchGroups()
+            this.fetchGroupMemberships()
+        },
         tryAcceptInvite(invite) {
             this.acceptGroupInvite(invite).then(() => {
                 this.fetchGroupInvites()
                 this.fetchGroups()
+                this.fetchGroupMemberships()
             }).catch(() => {
             })
         },
@@ -114,6 +137,7 @@ export default {
     mounted() {
         this.fetchGroups()
         this.fetchGroupInvites()
+        this.fetchGroupMemberships()
     }
 }
 </script>

frontend/src/views/Inventory.vue

@@ -150,11 +150,10 @@ export default {
             if (owner_identity_id === undefined) return null
             return shortenedRoute({kind: 'item', owner_identity_id, item_local_id: item.id})
         },
-        // Routes to Print.vue with this item's raw identity rather than a pre-built link.
-        // See docs/implementation.md#print-link-shape-for-personal-items.
         printLinkFor(item) {
-            if (!item.owner) return null
-            return {path: '/print', query: {kind: 'item', userHandle: item.owner, item: item.id}}
+            const userHandle = item.owner || item.owner_group
+            if (!userHandle) return null
+            return {path: '/print', query: {kind: 'item', userHandle, item: item.id}}
         },
     },
     async mounted() {

frontend/src/views/InventoryDetail.vue

@@ -46,7 +46,7 @@
                             Edit
                         </button>
                         <button type="submit" class="btn btn-danger"
-                                @click="deleteInventoryItem(item).then(() => $router.push('/inventory'))">
+                                @click="deleteInventoryItem(item).then(() => $router.push(ownerOverviewRoute(item)))">
                             <b-icon-trash></b-icon-trash>
                             Delete
                         </button>
@@ -68,7 +68,7 @@ import * as BIcons from "bootstrap-icons-vue";
 import BaseLayout from "@/components/BaseLayout.vue";
 import {mapActions, mapGetters, mapState} from "vuex";
 import AuthenticatedImage from "@/components/AuthenticatedImage.vue";
-import {decodeHandleFromUrl} from "@/router";
+import {decodeHandleFromUrl, ownerOverviewRoute} from "@/router";
 
 export default {
     name: "InventoryDetail",
@@ -94,23 +94,30 @@ export default {
     },
     computed: {
         ...mapGetters(["getNameFromHandle", "groupIdByHandle"]),
-        ...mapState(["user"]),
+        ...mapState(["user", "groupMemberships"]),
         decodedHandle() {
             return decodeHandleFromUrl(this.handle)
         },
+        // Am I a member of this group, hosted here (groupIdByHandle, from idmap) or elsewhere
+        // (groupMemberships - see GroupMembership/docs/design-in-progress/groups-mvp.md)? Either
+        // way the backend actually hosting the group is what authorizes the write - this is just
+        // enough of a client-side hint to show/hide the buttons for it.
+        isGroupMember() {
+            return this.decodedHandle in this.groupIdByHandle
+                || this.groupMemberships.some(m => m.handle === this.decodedHandle)
+        },
         // Edit/Delete require actual authorization (own item or member group), not just view
         // access - get_shared_item's friends_or_self() lets a friend view but never act.
         canEdit() {
-            return this.decodedHandle === this.user || this.decodedHandle in this.groupIdByHandle
+            return this.decodedHandle === this.user || this.isGroupMember
         },
-        // Printed labels only support a personal owner handle so far (see label.js's
-        // splitUserHandle); group items get no print link until that's supported too.
         canPrint() {
-            return this.decodedHandle === this.user
+            return this.decodedHandle === this.user || this.isGroupMember
         }
     },
     methods: {
-        ...mapActions(["fetchItemByHandle", "deleteInventoryItem"]),
+        ownerOverviewRoute,
+        ...mapActions(["fetchItemByHandle", "deleteInventoryItem", "fetchGroupMemberships"]),
         async loadItem() {
             this.item = await this.fetchItemByHandle({handle: this.decodedHandle, id: this.id}) || {}
         }
@@ -121,6 +128,9 @@ export default {
     },
     mounted() {
         this.loadItem()
+        if (this.decodedHandle.startsWith('#')) {
+            this.fetchGroupMemberships()
+        }
     }
 }
 </script>

frontend/src/views/InventoryEdit.vue

@@ -57,7 +57,8 @@
                             </div>
                             <div class="mb-3">
                                 <button type="submit" class="btn btn-primary" style="width: 100%"
-                                        @click="updateInventoryItem(item)">Update
+                                        @click="updateInventoryItem(item).then(updated => $router.push(ownerOverviewRoute(updated)))">
+                                    Update
                                 </button>
                             </div>
                         </div>
@@ -75,7 +76,7 @@ import BaseLayout from "@/components/BaseLayout.vue";
 import TagField from "@/components/TagField.vue";
 import PropertyField from "@/components/PropertyField.vue";
 import CombinedFileField from "@/components/CombinedFileField.vue";
-import {decodeHandleFromUrl} from "@/router";
+import {decodeHandleFromUrl, ownerOverviewRoute} from "@/router";
 
 export default {
     name: "InventoryEdit",
@@ -120,6 +121,7 @@ export default {
         }
     },
     methods: {
+        ownerOverviewRoute,
         ...mapActions(["fetchItemByHandle", "updateInventoryItem", "fetchInfo", "fetchStorageLocations"]),
         changeFiles(files) {
             this.item.files = files

frontend/src/views/InventoryNew.vue

@@ -66,7 +66,7 @@
                             </div>
                             <div class="mb-3">
                                 <button type="submit" class="btn btn-primary" style="width: 100%"
-                                        @click="createInventoryItem(item).then(() => $router.push('/inventory'))">Add
+                                        @click="createInventoryItem(item).then(created => $router.push(ownerOverviewRoute(created)))">Add
                                 </button>
                             </div>
                         </div>
@@ -84,6 +84,7 @@ import BaseLayout from "@/components/BaseLayout.vue";
 import TagField from "@/components/TagField.vue";
 import PropertyField from "@/components/PropertyField.vue";
 import CombinedFileField from "@/components/CombinedFileField.vue";
+import {ownerOverviewRoute} from "@/router";
 
 export default {
     name: "InventoryNew",
@@ -111,6 +112,7 @@ export default {
         }
     },
     methods: {
+        ownerOverviewRoute,
         ...mapActions(['createInventoryItem', 'fetchInfo', 'fetchStorageLocations', 'fetchGroups'])
     },
     computed: {

frontend/src/views/Print.vue

@@ -337,10 +337,7 @@ export default {
         };
     },
     computed: {
-        ...mapGetters(["identityIdByHandle"]),
-        // Plain passthroughs of the form's base/derived vars, keeping the template from importing
-        // label-layouts.js just for these. SHORT_URL_VAR/SHORT_ID_VAR exclusion: see
-        // docs/implementation.md#calculated-short-link-fields.
+        ...mapGetters(["identityIdByHandle", "groupIdByHandle"]),
         baseVars() {
             return BASE_VARS.filter(v => v !== SHORT_URL_VAR && v !== SHORT_ID_VAR);
         },
@@ -461,12 +458,17 @@ export default {
         varLabel(v) {
             return v.replace(/([a-z])([A-Z])/g, "$1 $2").replace(/^./, c => c.toUpperCase());
         },
-
-        // Builds the bare short-id.js token for the current fields. See docs/implementation.md#shortid-resolution.
         shortId(f) {
             if (!f.userHandle) {
                 return null;
             }
+            if (f.userHandle.startsWith("#")) {
+                const owner_group_id = this.groupIdByHandle[f.userHandle];
+                if (owner_group_id === undefined || !f.itemId) {
+                    return null;
+                }
+                return shortenedRoute({kind: "group_item", owner_group_id, item_local_id: f.itemId}).slice(1);
+            }
             const owner_identity_id = this.identityIdByHandle[f.userHandle];
             if (owner_identity_id === undefined) {
                 return null;

frontend/src/views/Register.vue

@@ -203,4 +203,8 @@ export default {
 .is-invalid .invalid-feedback {
     display: block;
 }
+
+.visually-hidden {
+    display: none;
+}
 </style>

frontend/src/views/Scan.vue

@@ -148,33 +148,14 @@ export default {
             error: null,
             insecureContext: window.isSecureContext,
             insecureOrigin: `${window.location.protocol}//${window.location.hostname}`,
-
-            // One-shot: cleared by maybeVisitFirstMatch as soon as it navigates, so it doesn't
-            // keep firing router.push for every later scan/decode while left switched on.
-            // Defaults on when the page itself was opened with ?navigate=immediate (e.g. a link
-            // shared for a "scan and go" workflow), so the toggle doesn't need a manual flip first.
             visitFirstMatch: this.$route.query.navigate === "immediate",
 
             cameraLog: [],
         };
     },
     methods: {
-        ...mapActions(["fetchItemByHandle", "fetchGroup", "fetchStorageLocations", "fetchIdMap"]),
+        ...mapActions(["fetchItemByHandle", "fetchStorageLocations", "fetchIdMap"]),
 
-        // Resolves entry.link into entry.description ("[#7] Cordless drill") for the non-URL
-        // formats classifyScanText recognizes - mutates the already-rendered entry in place once
-        // the lookup lands, rather than delaying the log/result list from showing the raw scanned
-        // text and link immediately. Left as `undefined` (template shows "resolving...") while in
-        // flight, and settles to a string or `null` (nothing else known to show, e.g. a workflow
-        // short id, or the owner/item genuinely couldn't be resolved).
-        //
-        // descriptionCache (keyed by the raw scanned text) memoizes the outcome - a still-in-frame
-        // code gets re-decoded and re-logged several times a second (see logDecode), and
-        // re-scanning the same printed label later is common too, so without this every repeat
-        // would re-fire the same fetchItemByHandle/fetchGroup/fetchStorageLocations/fetchIdMap
-        // round trip. Caching the in-flight promise itself (not just its settled value) also
-        // dedupes concurrent lookups for the same still-in-frame code, rather than firing one
-        // request per decode.
         resolveDescription(entry) {
             const {link, text} = entry;
             if (!link || link.href) {
@@ -185,10 +166,6 @@ export default {
                 return;
             }
             if (!this.descriptionCache.has(text)) {
-                // Wrapped as {error} rather than swallowed to null: a lookup can fail for very
-                // different reasons (not logged in, item not shared with this viewer, a genuine
-                // network error) and collapsing them all to "no description" made every one of
-                // them look identical to "nothing to show" - undiagnosable from the UI.
                 this.descriptionCache.set(text, this.describeLink(link).catch(e => ({error: e.message ?? String(e)})));
             }
             this.descriptionCache.get(text).then(result => {
@@ -198,19 +175,12 @@ export default {
                     return;
                 }
                 entry.description = result;
-                // Only a truthy description confirms the target actually exists - a null/empty
-                // one (unresolvable, or a kind with no title lookup wired up) shouldn't count as
-                // a "match" to auto-visit.
                 if (result) {
                     this.maybeVisitFirstMatch(link);
                 }
             });
         },
 
-        // Sends the viewer straight to the first scan this session that's confirmed to resolve
-        // (immediately for a plain URL, or once resolveDescription confirms a real target for a
-        // token/handle) while the "Visit first match" toggle is on. One-shot: switches the toggle
-        // back off so it doesn't fire again for every later scan of the same or another code.
         maybeVisitFirstMatch(link) {
             if (!this.visitFirstMatch || !link?.to) {
                 return;
@@ -242,8 +212,12 @@ export default {
                 return handle === undefined ? null : this.describeItem(handle, decoded.item_local_id);
             }
             if (decoded.kind === "group") {
-                const group = await this.fetchGroup({id: decoded.group_id});
-                return group ? group.handle : null;
+                let handle = this.$store.getters.groupHandleById[decoded.group_id];
+                if (handle === undefined) {
+                    await this.fetchIdMap();
+                    handle = this.$store.getters.groupHandleById[decoded.group_id];
+                }
+                return handle === undefined ? null : handle;
             }
             if (decoded.kind === "storage_location") {
                 if (!this.$store.state.storage_locations.length) {

frontend/vite.config.js

@@ -5,6 +5,30 @@ import {existsSync} from 'node:fs'
 import {defineConfig} from 'vite'
 import vue from '@vitejs/plugin-vue'
 
+// Vite's dev-server SPA fallback only rewrites a request to index.html when the last path
+// segment has no dot (it sniffs for a file extension). A route whose only/last segment is a
+// URL-encoded handle (e.g. /groups/+user@a.localhost, see encodeHandleForUrl in src/router.js)
+// legitimately contains a dot from the domain part, so a direct load/refresh 404s there unless
+// we pre-empt that check ourselves. Gating on both a text/html Accept header and an '@' in the
+// last segment keeps this from ever matching real asset requests or vite's own internal
+// @fs/@id/@vite module paths (which never carry an html Accept header).
+function handleUrlFallback() {
+    return {
+        name: 'handle-url-fallback',
+        configureServer(server) {
+            server.middlewares.use((req, res, next) => {
+                const accept = req.headers.accept || ''
+                const pathname = (req.url || '').split('?')[0]
+                const lastSegment = pathname.slice(pathname.lastIndexOf('/') + 1)
+                if (req.method === 'GET' && accept.includes('text/html') && lastSegment.includes('@')) {
+                    req.url = '/index.html'
+                }
+                next()
+            })
+        }
+    }
+}
+
 function gitCommit() {
     // deploy/dev/docker-compose.yml bind-mounts the repo's real .git dir at
     // /git (separate from /app, which only has the frontend/ subtree) -
@@ -23,7 +47,7 @@ function gitCommit() {
 }
 
 export default defineConfig({
-    plugins: [vue()],
+    plugins: [vue(), handleUrlFallback()],
     define: {
         __GIT_COMMIT__: JSON.stringify(gitCommit())
     },
@@ -44,6 +68,10 @@ export default defineConfig({
             //'Upgrade-Insecure-Requests': '1',
             'Content-Security-Policy': 'default-src \'self\';'
                 + ' script-src \'self\' \'wasm-unsafe-eval\' \'unsafe-eval\' \'unsafe-inline\';'
+                // Without this, worker-src falls back to script-src, which has no blob: source -
+                // CameraScanner.vue's decode Worker (built from a Blob URL) would be silently
+                // blocked by CSP rather than the app's own capability checks.
+                + ' worker-src \'self\' blob:;'
                 + ' style-src \'self\' \'unsafe-inline\';'
                 + ' img-src \'self\' * data: blob:;'
                 + ' connect-src * data:',