Added support for proxy configuration (#224)

* Create ProxyConfig class + Unit tests

* Use ProxyConfig in SpotifyLocalAPI

* Refactor WebProxy creation in ProxyConfig

* Use ProxyConfig in SpotifyWebAPI

* Add ProxyConfig parameter in GetAlbumArt methods

* Add ProxyConfig to WebAPIFactory

* Add proxy settings to Example app

* Fix ArgumentNullException in GetAlbumArtUrl when not using proxy

* Performed requested changes

- Removed redundant "this".
- Added necessary null checks.
- Added a ProxyConfig property to SpotifyLocalAPIConfig and removed constructor overloads with it in SpotifyLocalAPI and RemoteHandler.

* Updated Example app

Author: aleab

SpotifyAPI.Example/LocalControl.Designer.cs

@@ -10,14 +10,20 @@ namespace SpotifyAPI.Example
 {
     public partial class LocalControl : UserControl
     {
-        private readonly SpotifyLocalAPI _spotify;
+        private readonly SpotifyLocalAPIConfig _config;
+        private SpotifyLocalAPI _spotify;
         private Track _currentTrack;
 
         public LocalControl()
         {
             InitializeComponent();
+            
+            _config = new SpotifyLocalAPIConfig
+            {
+                ProxyConfig = new ProxyConfig()
+            };
 
-            _spotify = new SpotifyLocalAPI();
+            _spotify = new SpotifyLocalAPI(_config);
             _spotify.OnPlayStateChange += _spotify_OnPlayStateChange;
             _spotify.OnTrackChange += _spotify_OnTrackChange;
             _spotify.OnTrackTimeChange += _spotify_OnTrackTimeChange;
@@ -99,8 +105,8 @@ public async void UpdateTrack(Track track)
 
             trackInfoBox.Text = $@"Track Info - {uri?.Id}";
 
-            bigAlbumPicture.Image = track.AlbumResource != null ? await track.GetAlbumArtAsync(AlbumArtSize.Size640) : null;
-            smallAlbumPicture.Image = track.AlbumResource != null ? await track.GetAlbumArtAsync(AlbumArtSize.Size160) : null;
+            bigAlbumPicture.Image = track.AlbumResource != null ? await track.GetAlbumArtAsync(AlbumArtSize.Size640, _config.ProxyConfig) : null;
+            smallAlbumPicture.Image = track.AlbumResource != null ? await track.GetAlbumArtAsync(AlbumArtSize.Size160, _config.ProxyConfig) : null;
         }
 
         public void UpdatePlayingStatus(bool playing)
@@ -113,6 +119,36 @@ public void RefreshVolumeMixerVolume()
             volumeMixerLabel.Text = _spotify.GetSpotifyVolume().ToString(CultureInfo.InvariantCulture);
         }
 
+        private void applyProxyBtn_Click(object sender, EventArgs e)
+        {
+            _config.ProxyConfig.Host = proxyHostTextBox.Text;
+            _config.ProxyConfig.Port = (int)proxyPortUpDown.Value;
+            _config.ProxyConfig.Username = proxyUsernameTextBox.Text;
+            _config.ProxyConfig.Password = proxyPasswordTextBox.Text;
+
+            bool connected = _spotify.ListenForEvents;
+            if (connected)
+            {
+                // Reconnect using new proxy
+                _spotify.ListenForEvents = false;
+                _spotify.OnPlayStateChange -= _spotify_OnPlayStateChange;
+                _spotify.OnTrackChange -= _spotify_OnTrackChange;
+                _spotify.OnTrackTimeChange -= _spotify_OnTrackTimeChange;
+                _spotify.OnVolumeChange -= _spotify_OnVolumeChange;
+
+                _spotify.Dispose();
+
+                _spotify = new SpotifyLocalAPI(_config);
+                _spotify.OnPlayStateChange += _spotify_OnPlayStateChange;
+                _spotify.OnTrackChange += _spotify_OnTrackChange;
+                _spotify.OnTrackTimeChange += _spotify_OnTrackTimeChange;
+                _spotify.OnVolumeChange += _spotify_OnVolumeChange;
+
+                connectBtn.Text = @"Reconnecting...";
+                Connect();
+            }
+        }
+
         private void _spotify_OnVolumeChange(object sender, VolumeChangeEventArgs e)
         {
             if (InvokeRequired)

SpotifyAPI.Example/LocalControl.cs

@@ -15,6 +15,7 @@ namespace SpotifyAPI.Example
 {
     public partial class WebControl : UserControl
     {
+        private readonly ProxyConfig _proxyConfig;
         private SpotifyWebAPI _spotify;
 
         private PrivateProfile _profile;
@@ -25,8 +26,9 @@ public WebControl()
         {
             InitializeComponent();
 
+            _proxyConfig = new ProxyConfig();
+
             _savedTracks = new List<FullTrack>();
-            
         }
 
         private async void InitialSetup()
@@ -109,7 +111,8 @@ private async void RunAuthentication()
                 "26d287105e31491889f3cd293d85bfea",
                 Scope.UserReadPrivate | Scope.UserReadEmail | Scope.PlaylistReadPrivate | Scope.UserLibraryRead |
                 Scope.UserReadPrivate | Scope.UserFollowRead | Scope.UserReadBirthdate | Scope.UserTopRead | Scope.PlaylistReadCollaborative |
-                Scope.UserReadRecentlyPlayed | Scope.UserReadPlaybackState | Scope.UserModifyPlaybackState);
+                Scope.UserReadRecentlyPlayed | Scope.UserReadPlaybackState | Scope.UserModifyPlaybackState,
+                _proxyConfig);
 
             try
             {
@@ -125,5 +128,13 @@ private async void RunAuthentication()
 
             InitialSetup();
         }
+
+        private void applyProxyBtn_Click(object sender, EventArgs e)
+        {
+            _proxyConfig.Host = proxyHostTextBox.Text;
+            _proxyConfig.Port = (int)proxyPortUpDown.Value;
+            _proxyConfig.Username = proxyUsernameTextBox.Text;
+            _proxyConfig.Password = proxyPasswordTextBox.Text;
+        }
     }
 }