Merge pull request #380 from pusher/subscription-count-support

fbenevides · web-flow · commit 56fac7863784 · 2022-07-15T14:37:51.000+02:00
Handle pusher_internal:subscription_count event
diff --git a/README.md b/README.md
@@ -609,6 +609,19 @@ PusherChannel *myChannel = [pusher subscribeWithChannelName:@"my-channel"];
 
 This returns PusherChannel object, which events can be bound to.
 
+For non-presence channels, you can also provide a function that will be called when a client either subscribes or unsubscribes to a channel with the number of subscribers as a parameter. Also, this function is available as a parameter to `subscribe` function. 
+
+```swift
+let onSubscriptionCountChanged = { (count: Int) in
+    print("\(count) subscriptions")
+}
+
+let channel = pusher.subscribe(
+    channelName: "my-channel",
+    onSubscriptionCountChanged: onSubscriptionCountChanged
+)
+```
+
 ### Private channels
 
 Private channels are created in exactly the same way as public channels, except that they reside in the 'private-' namespace. This means prefixing the channel name:
diff --git a/Sources/Models/Constants.swift b/Sources/Models/Constants.swift
@@ -29,6 +29,7 @@ enum Constants {
             static let memberAdded              = "pusher_internal:member_added"
             static let memberRemoved            = "pusher_internal:member_removed"
             static let subscriptionSucceeded    = "pusher_internal:subscription_succeeded"
+            static let subscriptionCount        = "pusher_internal:subscription_count"
         }
     }
 
@@ -39,21 +40,22 @@ enum Constants {
     }
 
     enum JSONKeys {
-        static let activityTimeout  = "activity_timeout"
-        static let auth             = "auth"
-        static let channel          = "channel"
-        static let channelData      = "channel_data"
-        static let ciphertext       = "ciphertext"
-        static let code             = "code"
-        static let data             = "data"
-        static let event            = "event"
-        static let hash             = "hash"
-        static let message          = "message"
-        static let nonce            = "nonce"
-        static let presence         = "presence"
-        static let socketId         = "socket_id"
-        static let sharedSecret     = "shared_secret"
-        static let userId           = "user_id"
-        static let userInfo         = "user_info"
+        static let activityTimeout   = "activity_timeout"
+        static let auth              = "auth"
+        static let channel           = "channel"
+        static let channelData       = "channel_data"
+        static let ciphertext        = "ciphertext"
+        static let code              = "code"
+        static let data              = "data"
+        static let event             = "event"
+        static let hash              = "hash"
+        static let message           = "message"
+        static let nonce             = "nonce"
+        static let presence          = "presence"
+        static let socketId          = "socket_id"
+        static let sharedSecret      = "shared_secret"
+        static let userId            = "user_id"
+        static let userInfo          = "user_info"
+        static let subscriptionCount = "subscription_count"
     }
 }
diff --git a/Sources/Models/PusherChannel.swift b/Sources/Models/PusherChannel.swift
@@ -15,12 +15,19 @@ open class PusherChannel: NSObject {
             eventHandlersQueue.async(flags: .barrier) { self.eventHandlersInternal = newValue }
         }
     }
+    
+    private var _subscriptionCount: Int? = nil
+    public var subscriptionCount: Int? {
+        get { return _subscriptionCount }
+    }
+    
     open var subscribed = false
     public let name: String
     open weak var connection: PusherConnection?
     open var unsentEvents = [QueuedClientEvent]()
     public let type: PusherChannelType
     public var auth: PusherAuth?
+    open var onSubscriptionCountChanged: ((Int) -> Void)?
 
     // Wrap accesses to the decryption key in a serial queue because it will be accessed from multiple threads
     @nonobjc private var decryptionKeyQueue = DispatchQueue(label: "com.pusher.pusherswift-channel-decryption-key-\(UUID().uuidString)",
@@ -45,11 +52,17 @@ open class PusherChannel: NSObject {
 
         - returns: A new PusherChannel instance
     */
-    public init(name: String, connection: PusherConnection, auth: PusherAuth? = nil) {
+    public init(name: String, connection: PusherConnection, auth: PusherAuth? = nil, onSubscriptionCountChanged: ((Int) -> Void)? = nil) {
         self.name = name
         self.connection = connection
         self.auth = auth
         self.type = PusherChannelType(name: name)
+        self.onSubscriptionCountChanged = onSubscriptionCountChanged
+    }
+    
+    internal func updateSubscriptionCount(count: Int) {
+        self._subscriptionCount = count
+        self.onSubscriptionCountChanged?(count)
     }
 
     /**
diff --git a/Sources/Models/PusherChannels.swift b/Sources/Models/PusherChannels.swift
@@ -36,7 +36,8 @@ import Foundation
         connection: PusherConnection,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherChannel {
         if let channel = self.channels[name] {
             return channel
@@ -51,7 +52,10 @@ import Foundation
                     onMemberRemoved: onMemberRemoved
                 )
             } else {
-                newChannel = PusherChannel(name: name, connection: connection, auth: auth)
+                newChannel = PusherChannel(name: name,
+                                           connection: connection,
+                                           auth: auth,
+                                           onSubscriptionCountChanged: onSubscriptionCountChanged)
             }
             self.channels[name] = newChannel
             return newChannel
@@ -78,7 +82,8 @@ import Foundation
         connection: PusherConnection,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherPresenceChannel {
         if let channel = self.channels[channelName] as? PusherPresenceChannel {
             return channel
@@ -88,7 +93,8 @@ import Foundation
                 connection: connection,
                 auth: auth,
                 onMemberAdded: onMemberAdded,
-                onMemberRemoved: onMemberRemoved
+                onMemberRemoved: onMemberRemoved,
+                onSubscriptionCountChanged: onSubscriptionCountChanged
             )
             self.channels[channelName] = newChannel
             return newChannel
diff --git a/Sources/Models/PusherPresenceChannel.swift b/Sources/Models/PusherPresenceChannel.swift
@@ -29,12 +29,13 @@ public typealias PusherUserInfoObject = [String: AnyObject]
         connection: PusherConnection,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) {
         self.members = []
         self.onMemberAdded = onMemberAdded
         self.onMemberRemoved = onMemberRemoved
-        super.init(name: name, connection: connection, auth: auth)
+        super.init(name: name, connection: connection, auth: auth, onSubscriptionCountChanged: onSubscriptionCountChanged)
     }
 
     /**
diff --git a/Sources/ObjC/Pusher+ObjectiveC.swift b/Sources/ObjC/Pusher+ObjectiveC.swift
@@ -8,27 +8,35 @@ import Foundation
     func subscribe(
         channelName: String,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherChannel {
-        return self.subscribe(channelName, auth: nil, onMemberAdded: onMemberAdded, onMemberRemoved: onMemberRemoved)
+        return self.subscribe(channelName,
+                              auth: nil,
+                              onMemberAdded: onMemberAdded,
+                              onMemberRemoved: onMemberRemoved,
+                              onSubscriptionCountChanged: onSubscriptionCountChanged)
     }
 
     func subscribeToPresenceChannel(channelName: String) -> PusherPresenceChannel {
         return self.subscribeToPresenceChannel(channelName: channelName,
                                                auth: nil,
                                                onMemberAdded: nil,
-                                               onMemberRemoved: nil)
+                                               onMemberRemoved: nil,
+                                               onSubscriptionCountChanged: nil)
     }
 
     func subscribeToPresenceChannel(
         channelName: String,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherPresenceChannel {
         return self.subscribeToPresenceChannel(channelName: channelName,
                                                auth: nil,
                                                onMemberAdded: onMemberAdded,
-                                               onMemberRemoved: onMemberRemoved)
+                                               onMemberRemoved: onMemberRemoved,
+                                               onSubscriptionCountChanged: onSubscriptionCountChanged)
     }
 
     convenience init(withAppKey key: String, options: PusherClientOptions) {
diff --git a/Sources/PusherSwift.swift b/Sources/PusherSwift.swift
@@ -51,7 +51,8 @@ let CLIENT_NAME = "pusher-websocket-swift"
         _ channelName: String,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherChannel {
 
         let isEncryptedChannel = PusherChannel.isEncrypted(name: channelName)
@@ -64,7 +65,8 @@ let CLIENT_NAME = "pusher-websocket-swift"
             channelName: channelName,
             auth: auth,
             onMemberAdded: onMemberAdded,
-            onMemberRemoved: onMemberRemoved
+            onMemberRemoved: onMemberRemoved,
+            onSubscriptionCountChanged: onSubscriptionCountChanged
         )
     }
 
@@ -87,13 +89,15 @@ let CLIENT_NAME = "pusher-websocket-swift"
         channelName: String,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherPresenceChannel {
         return self.connection.subscribeToPresenceChannel(
             channelName: channelName,
             auth: auth,
             onMemberAdded: onMemberAdded,
-            onMemberRemoved: onMemberRemoved
+            onMemberRemoved: onMemberRemoved,
+            onSubscriptionCountChanged: onSubscriptionCountChanged
         )
     }
 
diff --git a/Sources/Services/PusherConnection.swift b/Sources/Services/PusherConnection.swift
@@ -104,14 +104,16 @@ import NWWebSocket
         channelName: String,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherChannel {
             let newChannel = channels.add(
                 name: channelName,
                 connection: self,
                 auth: auth,
                 onMemberAdded: onMemberAdded,
-                onMemberRemoved: onMemberRemoved
+                onMemberRemoved: onMemberRemoved,
+                onSubscriptionCountChanged: onSubscriptionCountChanged
             )
 
             guard self.connectionState == .connected else { return newChannel }
@@ -141,14 +143,16 @@ import NWWebSocket
         channelName: String,
         auth: PusherAuth? = nil,
         onMemberAdded: ((PusherPresenceChannelMember) -> Void)? = nil,
-        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil
+        onMemberRemoved: ((PusherPresenceChannelMember) -> Void)? = nil,
+        onSubscriptionCountChanged: ((Int) -> Void)? = nil
     ) -> PusherPresenceChannel {
         let newChannel = channels.addPresence(
             channelName: channelName,
             connection: self,
             auth: auth,
             onMemberAdded: onMemberAdded,
-            onMemberRemoved: onMemberRemoved
+            onMemberRemoved: onMemberRemoved,
+            onSubscriptionCountChanged: onSubscriptionCountChanged
         )
 
         guard self.connectionState == .connected else { return newChannel }
@@ -459,7 +463,7 @@ import NWWebSocket
                 }
             }
         }
-
+        
         let subscriptionEvent = event.copy(withEventName: Constants.Events.Pusher.subscriptionSucceeded)
         callGlobalCallbacks(event: subscriptionEvent)
         chan.handleEvent(event: subscriptionEvent)
@@ -549,6 +553,23 @@ import NWWebSocket
             Logger.shared.debug(for: .unableToRemoveMemberFromChannel)
         }
     }
+    
+    /**
+        Handle subscription count event
+     
+        - parameter event: The event to be processed
+     */
+    
+    private func handleSubscriptionCountEvent(event: PusherEvent) {
+        guard let channelName = event.channelName,
+              let channel = self.channels.find(name: channelName),
+              let subscriptionCountData = event.dataToJSONObject() as? [String: Any],
+              let count = subscriptionCountData[Constants.JSONKeys.subscriptionCount] as? Int else {
+            return
+        }
+        
+        channel.updateSubscriptionCount(count: count)
+    }
 
     /**
      Handles incoming error
@@ -607,6 +628,9 @@ import NWWebSocket
 
         case Constants.Events.PusherInternal.memberRemoved:
             handleMemberRemovedEvent(event: event)
+        
+        case Constants.Events.PusherInternal.subscriptionCount:
+            handleSubscriptionCountEvent(event: event)
 
         default:
             callGlobalCallbacks(event: event)
