Invite/kick now uses transactions so that you can know whether the device actually joined or not. It's a bit messy right now, should introduce some sugar to make it cleaner.

lib/roles/app.js

@@ -275,29 +275,6 @@ module.exports = function(options) {
 
     new Promise(function(resolve, reject) {
       socket.on('disconnect', resolve)
-        // Grouping
-        .on('group.invite', function(data) {
-          push.send([
-            wireutil.global
-          , wireutil.envelope(new wire.GroupMessage(
-              new wire.OwnerMessage(
-                user.email
-              , user.name
-              , user.group
-              )
-            , options.groupTimeout
-            , wireutil.toDeviceRequirements(data)
-            ))
-          ])
-        })
-        .on('group.kick', function(data) {
-          push.send([
-            user.group
-          , wireutil.envelope(new wire.UngroupMessage(
-              wireutil.toDeviceRequirements(data)
-            ))
-          ])
-        })
         // Touch events
         .on('input.touchDown', createTouchHandler(wire.TouchDownMessage))
         .on('input.touchMove', createTouchHandler(wire.TouchMoveMessage))
@@ -316,6 +293,36 @@ module.exports = function(options) {
           ])
         })
         // Transactions
+        .on('group.invite', function(channel, responseChannel, data) {
+          joinChannel(responseChannel)
+          push.send([
+            channel
+          , wireutil.transaction(
+              responseChannel
+            , new wire.GroupMessage(
+                new wire.OwnerMessage(
+                  user.email
+                , user.name
+                , user.group
+                )
+              , options.groupTimeout
+              , wireutil.toDeviceRequirements(data)
+              )
+            )
+          ])
+        })
+        .on('group.kick', function(channel, responseChannel, data) {
+          joinChannel(responseChannel)
+          push.send([
+            channel
+          , wireutil.transaction(
+              responseChannel
+            , new wire.UngroupMessage(
+                wireutil.toDeviceRequirements(data)
+              )
+            )
+          ])
+        })
         .on('tx.cleanup', function(channel) {
           leaveChannel(channel)
         })

lib/roles/device.js

@@ -342,15 +342,65 @@ module.exports = function(options) {
         wireutil.makeDeviceIdentityMessage(options.serial, identity)])
     })
     .on(wire.GroupMessage, function(channel, message) {
-      if (!isGrouped() &&
-          devutil.matchesRequirements(identity, message.requirements)) {
-        joinGroup(message.owner, message.timeout)
+      var seq = 0
+      if (devutil.matchesRequirements(identity, message.requirements)) {
+        if (!isGrouped()) {
+          joinGroup(message.owner, message.timeout)
+          push.send([
+            channel
+          , wireutil.envelope(new wire.TransactionDoneMessage(
+              options.serial
+            , seq++
+            , true
+            ))
+          ])
+        }
+        else if (isOwnedBy(message.owner)) {
+          push.send([
+            channel
+          , wireutil.envelope(new wire.TransactionDoneMessage(
+              options.serial
+            , seq++
+            , true
+            ))
+          ])
+        }
+        else {
+          push.send([
+            channel
+          , wireutil.envelope(new wire.TransactionDoneMessage(
+              options.serial
+            , seq++
+            , false
+            ))
+          ])
+        }
       }
     })
     .on(wire.UngroupMessage, function(channel, message) {
-      if (isGrouped() &&
-          devutil.matchesRequirements(identity, message.requirements)) {
-        leaveGroup()
+      var seq = 0
+      if (devutil.matchesRequirements(identity, message.requirements)) {
+        if (isGrouped()) {
+          leaveGroup()
+          push.send([
+            channel
+          , wireutil.envelope(new wire.TransactionDoneMessage(
+              options.serial
+            , seq++
+            , true
+            ))
+          ])
+        }
+        else {
+          push.send([
+            channel
+          , wireutil.envelope(new wire.TransactionDoneMessage(
+              options.serial
+            , seq++
+            , true
+            ))
+          ])
+        }
       }
     })
     .on(wire.TouchDownMessage, function(channel, message) {
@@ -526,6 +576,10 @@ module.exports = function(options) {
     ])
   }
 
+  function isOwnedBy(someOwner) {
+    return owner && owner.group == someOwner.group
+  }
+
   function joinGroup(newOwner, timeout) {
     log.info('Now owned by "%s"', newOwner.email)
     log.info('Subscribing to group channel "%s"', newOwner.group)

res/app/components/stf/user/group/group-service.js

@@ -1,6 +1,6 @@
 var _ = require('lodash')
 
-module.exports = function GroupServiceFactory($rootScope, $http, socket, UserService) {
+module.exports = function GroupServiceFactory($rootScope, $http, socket, UserService, TransactionService) {
   var groupService = {
   }
 
@@ -47,17 +47,35 @@ module.exports = function GroupServiceFactory($rootScope, $http, socket, UserSer
     })
   })
 
-  groupService.invite = function (requirements) {
-    UserService.user().then(function (user) {
-      socket.emit('group.invite', requirements)
+  groupService.invite = function (device) {
+    return UserService.user().then(function (user) {
+      var tx = TransactionService.create([device])
+      socket.emit('group.invite', device.channel, tx.channel, {
+        serial: {
+          value: device.serial
+        , match: 'exact'
+        }
+      })
+      return tx.promise.then(function(results) {
+        return results[0].success
+      })
     })
   }
 
-  groupService.kick = function (requirements) {
-    UserService.user().then(function (user) {
-      socket.emit('group.kick', requirements)
+  groupService.kick = function (device) {
+    return UserService.user().then(function (user) {
+      var tx = TransactionService.create([device])
+      socket.emit('group.kick', device.channel, tx.channel, {
+        serial: {
+          value: device.serial
+        , match: 'exact'
+        }
+      })
+      return tx.promise.then(function(results) {
+        return results[0].success
+      })
     })
   }
 
   return groupService
-}
+}