Start cameradar server to communicate with GUI

server/actor/pubsub.go

@@ -0,0 +1,48 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package actor
+
+// Sub/Unsub event type
+const (
+	SubscribeEvent   = "subscribe"
+	UnsubscribeEvent = "unsubscribe"
+)
+
+// Subscription contains a sub/unsub event
+type Subscription struct {
+	Command          string
+	Channel          string
+	SubscribersCount uint
+}
+
+// Publication contains a publish event
+type Publication struct {
+	Channel string
+	Data    string
+}
+
+// PubSub is a generic interface for publishing data to subscribers using channels
+// It exposes subscriptions events so the controller can create/delete
+// data sources depending on the channels users subscribe to.
+// ex: launch a camera stream only when users subscribe to it
+type PubSub interface {
+	Run()
+	Sub() <-chan *Subscription
+	Pub() chan<- *Publication
+}
+
+// ChannelAccessChecker allows to check for accesses on a given channel
+type ChannelAccessChecker interface {
+	CheckAccess(channel, accessToken string) bool
+	ClearCache(accessToken string)
+}