Created queue system to hold pending commands until YT is ready

YouTubePlayer/YouTubePlayer/YouTubePlayerView.swift

@@ -6,6 +6,7 @@
 //  Copyright (c) 2014 Giles Van Gruisen. All rights reserved.
 //
 
+import Combine
 import UIKit
 import WebKit
 
@@ -14,6 +15,7 @@ public class YouTubePlayerView: UIView {
 
     public enum State {
         case idle
+        case loading
         case ready(PlayerState)
         case error(PlayerError)
 
@@ -23,11 +25,29 @@ public class YouTubePlayerView: UIView {
             }
             return false
         }
+
+        fileprivate var isReady: Bool {
+            if case .ready = self {
+                return true
+            }
+            return false
+        }
+
+        fileprivate var isLoading: Bool {
+            if case .loading = self {
+                return true
+            }
+            return false
+        }
     }
 
     @Published private(set) public var state: State = .idle
     @Published private(set) public var quality: PlaybackQuality = .auto
 
+    private var stateWatcherCancellable: AnyCancellable?
+
+    private var queue: [(String, ((Any?) -> Void)?)] = []
+
     /// A Boolean value that indicates whether HTML5 videos play inline or use the native full-screen controller.
     public var allowsInlineMediaPlayback = false
 
@@ -140,19 +160,24 @@ public extension YouTubePlayerView {
 
 private extension YouTubePlayerView {
     func setupPlayer(with parameters: PlayerParameters) {
+        state = .loading
+
         guard let path = Bundle(for: YouTubePlayerView.self).path(forResource: "YTPlayer", ofType: "html") else {
             printLog("Unable to get the path of the YTPlayer.html")
+            state = .error(.unexpected)
             return
         }
 
         guard let rawHTMLString = try? String(contentsOfFile: path) else {
             printLog("Unable to get HTML from player file in bundle")
+            state = .error(.unexpected)
             return
         }
 
         guard let encoded = try? JSONEncoder().encode(parameters),
               let jsonParameters = String(data: encoded, encoding: .utf8) else {
             printLog("Unable to get JSON serialized parameters string")
+            state = .error(.invalidParameter)
             return
         }
 
@@ -163,19 +188,6 @@ private extension YouTubePlayerView {
         webView.loadHTMLString(htmlString, baseURL: URL(string: "about:blank"))
     }
 
-    func evaluatePlayerCommand(_ command: String, completion: ((Any?) -> Void)? = nil) {
-        let fullCommand = "player." + command + ";"
-        webView.evaluateJavaScript(fullCommand) { (result, error) in
-            if let error = error, (error as NSError).code != 5 { // NOTE: ignore :Void return
-                print(error)
-                printLog("Error executing javascript")
-                completion?(nil)
-            }
-
-            completion?(result)
-        }
-    }
-
     func handleJSEvent(_ eventURL: URL) {
         // Data is not always used,q that's why not guarding
         let data = eventURL.queryValue(for: "data")
@@ -201,6 +213,39 @@ private extension YouTubePlayerView {
             }
         }
     }
+
+    func evaluatePlayerCommand(_ command: String, completion: ((Any?) -> Void)? = nil) {
+        guard state.isLoading else {
+            evaluate(command, completion: completion)
+            return
+        }
+
+        // Queue up commands if YT is still loading and process them once YT is ready
+        queue.append((command, completion))
+
+        if stateWatcherCancellable == nil {
+            stateWatcherCancellable = $state.sink { [weak self] state in
+                guard let self, state.isReady else { return }
+                for (command, completion) in self.queue {
+                    self.evaluate(command, completion: completion)
+                }
+                self.queue.removeAll()
+                self.stateWatcherCancellable = nil
+            }
+        }
+    }
+
+    func evaluate(_ command: String, completion: ((Any?) -> Void)? = nil) {
+        let fullCommand = "player." + command + ";"
+        webView.evaluateJavaScript(fullCommand) { (result, error) in
+            if let error = error, (error as NSError).code != 5 { // NOTE: ignore :Void return
+                printLog("Error executing javascript: \(error.localizedDescription)")
+                completion?(nil)
+            }
+
+            completion?(result)
+        }
+    }
 }
 
 

YouTubePlayerExample/YouTubePlayerExample/ViewController.swift

@@ -53,27 +53,43 @@ class ViewController: UIViewController {
         loadVideo()
     }
 
-    private func loadVideo() {
+    @IBAction func loadPlaylist(sender: UIButton) {
+        playerView.loadPlaylistID("PLOU2XLYxmsILw2VmhxUWyd_imCrJef_iz")
+        playerView.playVideo()
+        getDuration()
+    }
+
+    @IBAction func currentTime(sender: UIButton) {
+        getCurrentTime()
+    }
+
+    @IBAction func duration(sender: UIButton) {
+        getDuration()
+    }
+}
+
+// MARK: - Player helpers
+
+private extension ViewController {
+    func loadVideo() {
         playerView.playerParams.playsInline = true
         playerView.playerParams.showControls = false
         playerView.playerParams.startAt = 180
         playerView.playerParams.showRecommendedFromOtherChannels = true
         playerView.loadVideoID("UF8uR6Z6KLc")
+        playerView.playVideo()
+        getDuration()
     }
 
-    @IBAction func loadPlaylist(sender: UIButton) {
-        playerView.loadPlaylistID("PLOU2XLYxmsILw2VmhxUWyd_imCrJef_iz")
-    }
-
-    @IBAction func currentTime(sender: UIButton) {
-        playerView.getCurrentTime(completion: { (time) in
+    func getCurrentTime() {
+        playerView.getCurrentTime { time in
             let title = String(format: "Current Time %.2f", time ?? 0)
             self.currentTimeButton.setTitle(title, for: .normal)
-        })
+        }
     }
-    
-    @IBAction func duration(sender: UIButton) {
-        playerView.getDuration { (duration) in
+
+    func getDuration() {
+        playerView.getDuration { duration in
             let title = String(format: "Duration %.2f", duration ?? 0)
             self.durationButton.setTitle(title, for: .normal)
         }