Add subscriptionCount delegate function

Author: fbenevides

Sources/Models/Constants.swift

@@ -23,12 +23,14 @@ enum Constants {
             static let unsubscribe              = "pusher:unsubscribe"
             static let subscriptionError        = "pusher:subscription_error"
             static let subscriptionSucceeded    = "pusher:subscription_succeeded"
+            static let subscriptionCount        = "pusher:subscription_count"
         }
 
         enum PusherInternal {
             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 +41,22 @@ 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"
     }
 }

Sources/Models/PusherChannel.swift

@@ -21,6 +21,7 @@ open class PusherChannel: NSObject {
     open var unsentEvents = [QueuedClientEvent]()
     public let type: PusherChannelType
     public var auth: PusherAuth?
+    public var subscriptionCount: Int
 
     // 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)",
@@ -50,6 +51,7 @@ open class PusherChannel: NSObject {
         self.connection = connection
         self.auth = auth
         self.type = PusherChannelType(name: name)
+        self.subscriptionCount = 0
     }
 
     /**

Sources/Protocols/PusherDelegate.swift

@@ -8,4 +8,5 @@ import Foundation
     @objc optional func failedToSubscribeToChannel(name: String, response: URLResponse?, data: String?, error: NSError?)
     @objc optional func failedToDecryptEvent(eventName: String, channelName: String, data: String?)
     @objc(receivedError:) optional func receivedError(error: PusherError)
+    @objc optional func subscriptionCountReceived(count: Int)
 }

Sources/Services/PusherConnection.swift

@@ -549,6 +549,22 @@ import NWWebSocket
             Logger.shared.debug(for: .unableToRemoveMemberFromChannel)
         }
     }
+    
+    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.subscriptionCount = count
+        
+        let subscriptionEvent = event.copy(withEventName: Constants.Events.Pusher.subscriptionCount)
+        channel.handleEvent(event: subscriptionEvent)
+        
+        self.delegate?.subscriptionCountReceived?(count: count)
+    }
 
     /**
      Handles incoming error
@@ -607,6 +623,9 @@ import NWWebSocket
 
         case Constants.Events.PusherInternal.memberRemoved:
             handleMemberRemovedEvent(event: event)
+        
+        case Constants.Events.PusherInternal.subscriptionCount:
+            handleSubscriptionCountEvent(event: event)
 
         default:
             callGlobalCallbacks(event: event)