Update proxy pattern examples

Author: nemanjarogic

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/CachingProxyExecutor.cs

@@ -1,4 +1,5 @@
 using BuildingBlocks;
+using ProxyLibrary.CachingProxyExample.Manager;
 using ProxyLibrary.CachingProxyExample.Proxy;
 using ProxyLibrary.CachingProxyExample.ThirdParty;
 
@@ -19,7 +20,7 @@ public static void Execute()
         youtubeManager.PlayVideo(2);
 
         // Video 1 should be cached.
-        // Request to third party service will not be issued.
+        // Therefore, a request to the third party service shouldn't be issued.
         youtubeManager.PlayVideo(1);
     }
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/Common/IYoutubeOperations.cs

@@ -6,8 +6,6 @@
 public interface IYoutubeOperations
 {
     VideoMetadata GetVideoMetadata(int id);
-
     Video DownloadVideo(int id);
-
     IEnumerable<VideoMetadata> ShowHomepage();
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/Common/Video.cs

@@ -3,6 +3,5 @@
 public class Video
 {
     public int Id { get; set; }
-
-    public string Content { get; set; }
-}
+    public string Content { get; set; } = string.Empty;
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/Common/VideoMetadata.cs

@@ -3,8 +3,6 @@
 public class VideoMetadata
 {
     public int Id { get; set; }
-
-    public string Name { get; set; }
-
-    public string Description { get; set; }
-}
+    public string Name { get; set; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/Manager/YoutubeManager.cs

@@ -1,12 +1,11 @@
 using ProxyLibrary.CachingProxyExample.Common;
 
-namespace ProxyLibrary.CachingProxyExample;
+namespace ProxyLibrary.CachingProxyExample.Manager;
 
 /// <summary>
 /// The client class, which used to work directly with a service object,
 /// stays unchanged as long as it works with the service object through an interface.
-/// We can safely pass a proxy object instead of a real service object since
-/// they both implement the same interface.
+/// We can safely pass a proxy object instead of a real service object since they both implement the same interface.
 /// </summary>
 public class YoutubeManager
 {
@@ -31,10 +30,10 @@ public void PlayVideo(int id)
     {
         Console.WriteLine("\nPlaying video...");
 
-        var video = _youtube.DownloadVideo(id);
-        Console.WriteLine($"Streaming started... Content: {video.Content}");
-
         var metadata = _youtube.GetVideoMetadata(id);
         Console.WriteLine($"Metadata loaded...Name: '{metadata.Name}' and description: '{metadata.Description}'");
+
+        var video = _youtube.DownloadVideo(id);
+        Console.WriteLine($"Streaming started... Content: {video.Content}");
     }
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/Proxy/CachedYoutube.cs

@@ -26,7 +26,7 @@ public CachedYoutube(Youtube youtubeService)
 
     public Video DownloadVideo(int id)
     {
-        if (!_contentCache.TryGetValue(id, out Video video))
+        if (!_contentCache.TryGetValue(id, out var video))
         {
             video = _youtubeService.DownloadVideo(id);
             _contentCache.Add(video.Id, video);
@@ -37,7 +37,7 @@ public Video DownloadVideo(int id)
 
     public VideoMetadata GetVideoMetadata(int id)
     {
-        if (!_metadataCache.TryGetValue(id, out VideoMetadata metadata))
+        if (!_metadataCache.TryGetValue(id, out var metadata))
         {
             metadata = _youtubeService.GetVideoMetadata(id);
             _metadataCache.Add(metadata.Id, metadata);
@@ -48,18 +48,20 @@ public VideoMetadata GetVideoMetadata(int id)
 
     public IEnumerable<VideoMetadata> ShowHomepage()
     {
-        // Naive logic - prepare homepage using only cached data
-        IEnumerable<VideoMetadata> videosMetadataForHomepage = _metadataCache.Values;
+        // Naive logic - prepare the homepage using only cached data.
+        IEnumerable<VideoMetadata> metadataForHomepage = _metadataCache.Values;
 
-        if (!videosMetadataForHomepage.Any())
+        if (!metadataForHomepage.Any())
         {
-            videosMetadataForHomepage = _youtubeService.ShowHomepage();
-            foreach (var videoMetadata in videosMetadataForHomepage)
+            // Nothing is cached on our side yet.
+            // Send a network request to the Youtube in order to get enough information for showing the homepage.
+            metadataForHomepage = _youtubeService.ShowHomepage();
+            foreach (var videoMetadata in metadataForHomepage)
             {
                 _metadataCache.Add(videoMetadata.Id, videoMetadata);
             }
         }
 
-        return videosMetadataForHomepage;
+        return metadataForHomepage;
     }
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/ThirdParty/ContentStorage.cs

@@ -18,13 +18,13 @@ public ContentStorage()
 
     public Video GetById(int id)
     {
-        Console.WriteLine($"Get content for video with ID: {id} from the content storage...");
+        Console.WriteLine($"Getting content for the video with ID: {id} from the content storage...");
 
-        if (!_videos.TryGetValue(id, out Video content))
+        if (!_videos.TryGetValue(id, out var video))
         {
             throw new Exception($"ID: {id} is unknown to content storage.");
         }
 
-        return content;
+        return video;
     }
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/ThirdParty/MetadataStorage.cs

@@ -18,19 +18,19 @@ public MetadataStorage()
 
     public IEnumerable<VideoMetadata> GetAll()
     {
-        Console.WriteLine("Get metadata for all videos from the metadata storage...");
+        Console.WriteLine("Getting metadata for all videos from the metadata storage...");
         return _videos.Values;
     }
 
     public VideoMetadata GetById(int id)
     {
-        Console.WriteLine($"Get metadata for video with ID: {id} from the metadata storage...");
+        Console.WriteLine($"Getting metadata for the video with ID: {id} from the metadata storage...");
 
-        if (!_videos.TryGetValue(id, out VideoMetadata video))
+        if (!_videos.TryGetValue(id, out var videoMetadata))
         {
             throw new Exception($"ID: {id} is unknown to metadata storage.");
         }
 
-        return video;
+        return videoMetadata;
     }
-}
+}

src/StructuralPatterns/Proxy/ProxyLibrary/CachingProxyExample/ThirdParty/Youtube.cs

@@ -11,21 +11,12 @@ namespace ProxyLibrary.CachingProxyExample.ThirdParty;
 /// </summary>
 public class Youtube : IYoutubeOperations
 {
-    private readonly ContentStorage _contentStorage = new ContentStorage();
-    private readonly MetadataStorage _metadataStorage = new MetadataStorage();
+    private readonly ContentStorage _contentStorage = new();
+    private readonly MetadataStorage _metadataStorage = new();
 
-    public Video DownloadVideo(int id)
-    {
-        return _contentStorage.GetById(id);
-    }
+    public Video DownloadVideo(int id) => _contentStorage.GetById(id);
 
-    public VideoMetadata GetVideoMetadata(int id)
-    {
-        return _metadataStorage.GetById(id);
-    }
+    public VideoMetadata GetVideoMetadata(int id) => _metadataStorage.GetById(id);
 
-    public IEnumerable<VideoMetadata> ShowHomepage()
-    {
-        return _metadataStorage.GetAll();
-    }
-}
+    public IEnumerable<VideoMetadata> ShowHomepage() => _metadataStorage.GetAll();
+}

src/StructuralPatterns/Proxy/ProxyLibrary/LoggingProxyExample/Client.cs

@@ -8,8 +8,5 @@
 /// </summary>
 public class Client
 {
-    public void PerformOperation(ISubject subject)
-    {
-        subject.Request();
-    }
-}
+    public void PerformOperation(ISubject subject) => subject.Request();
+}