#17 Add ability to configure logging using WithLogger method in main …

…Client and Providers. Added Instrumental flag to the ResponseMessage.

LyricsScraperNET.Client/Program.cs

@@ -12,6 +12,7 @@
 using LyricsScraperNET.Models.Responses;
 using System.Threading.Tasks;
 using System;
+using Microsoft.Extensions.Logging;
 
 class Program
 {
@@ -28,11 +29,23 @@ static async Task Main()
         //var result = ExampleWithCertainProvider(artistToSearch, songToSearch);
 
         //// Checking if something was found. 
-        //// If not, search errors can be found in the logs. 
+        //// May not be found in two cases:
+        //// 1) search errors can be found in the logs or in response fields like ResponseStatusCode and ResponseMessage.
+        //// 2) The requested song contains only the instrumental, no lyrics. In this case the flag will be true.
         if (result.IsEmpty())
         {
-            Console.ForegroundColor = ConsoleColor.Red;
-            Console.WriteLine($"Can't find lyrics for: {artistToSearch} - {songToSearch}");
+            if (result.Instrumental)
+            {
+                Console.ForegroundColor = ConsoleColor.Gray;
+                Console.WriteLine("This song is instrumental.\r\nIt does not contain any lyrics");
+            }
+            else
+            {
+                Console.ForegroundColor = ConsoleColor.Red;
+                Console.WriteLine($"Can't find lyrics for: [ {artistToSearch} - {songToSearch} ]. " +
+                    $"Status code: [ {result.ResponseStatusCode} ]. " +
+                    $"Response message: [ {result.ResponseMessage} ].");
+            }
             Console.ResetColor();
 
             Console.ReadLine();
@@ -41,13 +54,13 @@ static async Task Main()
 
         //// Output result to console
         Console.ForegroundColor = ConsoleColor.Yellow;
-        Console.WriteLine($"{artistToSearch} - {songToSearch}\r\n");
+        Console.WriteLine($"[ {artistToSearch} - {songToSearch} ]\r\n");
         Console.ResetColor();
 
         Console.WriteLine(result.LyricText);
 
         Console.ForegroundColor = ConsoleColor.Magenta;
-        Console.WriteLine($"\r\nThis text was found by {result.ExternalProviderType}\r\n");
+        Console.WriteLine($"\r\nThis lyric was found by [ {result.ExternalProviderType} ]\r\n");
         Console.ResetColor();
 
         Console.ReadLine();
@@ -105,6 +118,16 @@ ILyricsScraperClient lyricsScraperClient
                 .WithSongLyrics()
                 .WithLyricFind();
 
+        // To enable library logging, the LoggerFactory must be configured and passed to the client.
+        var loggerFactory = LoggerFactory.Create(builder =>
+        {
+            builder.AddFilter("Microsoft", LogLevel.Warning)
+                   .AddFilter("System", LogLevel.Warning)
+                   .AddFilter("LyricsScraperNET", LogLevel.Trace)
+                   .AddConsole();
+        });
+        lyricsScraperClient.WithLogger(loggerFactory);
+
         //// Another way to configure:
         //// 1. First create instance of LyricScraperClient.
         // ILyricsScraperClient lyricsScraperClient = new LyricsScraperClient();

LyricsScraperNET/Extensions/SearchResultExtensions.cs

@@ -29,5 +29,11 @@ internal static SearchResult AppendResponseMessage(this SearchResult searchResul
                 : responseMessage;
             return searchResult;
         }
+
+        internal static SearchResult AddInstrumental(this SearchResult searchResult, bool instrumental)
+        {
+            searchResult.Instrumental = instrumental;
+            return searchResult;
+        }
     }
 }

LyricsScraperNET/ILyricsScraperClient.cs

@@ -2,6 +2,7 @@
 using LyricsScraperNET.Models.Responses;
 using LyricsScraperNET.Providers.Abstract;
 using LyricsScraperNET.Providers.Models;
+using Microsoft.Extensions.Logging;
 using System.Threading.Tasks;
 
 namespace LyricsScraperNET
@@ -49,5 +50,11 @@ public interface ILyricsScraperClient
         /// Calling the lyrics search method will return an empty result.
         /// </summary>
         void Disable();
+
+        /// <summary>
+        /// Creates a new ILogger instance from <paramref name="loggerFactory"/>.
+        /// Can be useful for error analysis if the lyric text is not found.
+        /// </summary>
+        void WithLogger(ILoggerFactory loggerFactory);
     }
 }

LyricsScraperNET/LyricsScraperClient.cs

@@ -16,8 +16,8 @@ namespace LyricsScraperNET
 {
     public sealed class LyricsScraperClient : ILyricsScraperClient
     {
-
-        private readonly ILogger<LyricsScraperClient> _logger;
+        private ILoggerFactory _loggerFactory;
+        private ILogger<LyricsScraperClient> _logger;
 
         private List<IExternalProvider> _externalProviders;
         private readonly ILyricScraperClientConfig _lyricScraperClientConfig;
@@ -200,7 +200,11 @@ public void AddProvider(IExternalProvider provider)
             if (IsEmptyProvidersList())
                 _externalProviders = new List<IExternalProvider>();
             if (!_externalProviders.Contains(provider))
+            {
+                if (_loggerFactory != null)
+                    provider.WithLogger(_loggerFactory);
                 _externalProviders.Add(provider);
+            }
             else
                 _logger?.LogWarning($"External provider {provider} already added");
         }
@@ -219,9 +223,7 @@ public void Enable()
                 return;
 
             foreach (var provider in _externalProviders)
-            {
                 provider.Enable();
-            }
         }
 
         public void Disable()
@@ -230,9 +232,19 @@ public void Disable()
                 return;
 
             foreach (var provider in _externalProviders)
-            {
                 provider.Disable();
-            }
+        }
+
+        public void WithLogger(ILoggerFactory loggerFactory)
+        {
+            _loggerFactory = loggerFactory;
+            _logger = loggerFactory.CreateLogger<LyricsScraperClient>();
+
+            if (IsEmptyProvidersList())
+                return;
+
+            foreach (var provider in _externalProviders)
+                provider.WithLogger(loggerFactory);
         }
 
         private bool IsEmptyProvidersList() => _externalProviders == null || !_externalProviders.Any();

LyricsScraperNET/Models/Responses/SearchResult.cs

@@ -47,6 +47,11 @@ internal SearchResult(string lyricText, ExternalProviderType externalProviderTyp
         /// </summary>
         public string ResponseMessage { get; internal set; } = string.Empty;
 
+        /// <summary>
+        /// The flag indicates that the search results are for music only, without text.
+        /// </summary>
+        public bool Instrumental { get; internal set; } = false;
+
         /// <summary>
         /// Returns true if the field <seealso cref="LyricText"/> is empty.
         /// </summary>

LyricsScraperNET/Providers/AZLyrics/AZLyricsProvider.cs

@@ -11,7 +11,7 @@ namespace LyricsScraperNET.Providers.AZLyrics
 {
     public sealed class AZLyricsProvider : ExternalProviderBase
     {
-        private readonly ILogger<AZLyricsProvider> _logger;
+        private ILogger<AZLyricsProvider> _logger;
         private readonly IExternalUriConverter _uriConverter;
 
         private const string _lyricStart = "<!-- Usage of azlyrics.com content by any third-party lyrics provider is prohibited by our licensing agreement. Sorry about that. -->";
@@ -96,6 +96,11 @@ protected override async Task<SearchResult> SearchLyricAsync(Uri uri)
 
         #endregion
 
+        public override void WithLogger(ILoggerFactory loggerFactory)
+        {
+            _logger = loggerFactory.CreateLogger<AZLyricsProvider>();
+        }
+
         private SearchResult PostProcessLyric(Uri uri, string text)
         {
             if (string.IsNullOrEmpty(text))

LyricsScraperNET/Providers/Abstract/ExternalProviderBase.cs

@@ -1,6 +1,7 @@
 using LyricsScraperNET.Models.Requests;
 using LyricsScraperNET.Models.Responses;
 using LyricsScraperNET.Network.Abstract;
+using Microsoft.Extensions.Logging;
 using System;
 using System.Threading.Tasks;
 
@@ -95,5 +96,8 @@ public void Disable()
             if (Options != null)
                 Options.Enabled = false;
         }
+
+        public virtual void WithLogger(ILoggerFactory loggerFactory)
+            => throw new NotImplementedException();
     }
 }

LyricsScraperNET/Providers/Abstract/IExternalProvider.cs

@@ -1,6 +1,7 @@
 using LyricsScraperNET.Models.Requests;
 using LyricsScraperNET.Models.Responses;
 using LyricsScraperNET.Network.Abstract;
+using Microsoft.Extensions.Logging;
 using System.Threading.Tasks;
 
 namespace LyricsScraperNET.Providers.Abstract
@@ -27,5 +28,7 @@ public interface IExternalProvider
         void Enable();
 
         void Disable();
+
+        void WithLogger(ILoggerFactory loggerFactory);
     }
 }

LyricsScraperNET/Providers/Genius/GeniusProvider.cs

@@ -17,7 +17,7 @@ namespace LyricsScraperNET.Providers.Genius
 {
     public sealed class GeniusProvider : ExternalProviderBase
     {
-        private readonly ILogger<GeniusProvider> _logger;
+        private ILogger<GeniusProvider> _logger;
         private readonly IExternalUriConverter _uriConverter;
 
         // Format: "artist song". Example: "Parkway Drive Carrion".
@@ -26,6 +26,10 @@ public sealed class GeniusProvider : ExternalProviderBase
         private const string _referentFragmentNodesXPath = "//a[contains(@class, 'ReferentFragmentVariantdesktop') or contains(@class, 'ReferentFragmentdesktop')]";
         private const string _lyricsContainerNodesXPath = "//div[@data-lyrics-container]";
 
+        // In case of instrumental song without a lyric.
+        private const string _lyricsPlaceholderNodesXPath = "//div[contains(@class, 'LyricsPlaceholder')]";
+        private const string _instrumentalLyricText = "This song is an instrumental";
+
         #region Constructors
 
         public GeniusProvider()
@@ -71,7 +75,10 @@ protected override SearchResult SearchLyric(Uri uri)
         {
             var htmlPageBody = WebClient.Load(uri);
 
-            return new SearchResult(GetParsedLyricFromHtmlPageBody(htmlPageBody), Models.ExternalProviderType.Genius);
+            var lyricResult = GetParsedLyricFromHtmlPageBody(htmlPageBody, out var instrumental);
+
+            return new SearchResult(lyricResult, Models.ExternalProviderType.Genius)
+                .AddInstrumental(instrumental);
         }
 
         protected override SearchResult SearchLyric(string artist, string song)
@@ -94,7 +101,7 @@ protected override SearchResult SearchLyric(string artist, string song)
 
             return !string.IsNullOrWhiteSpace(lyricUrl)
                 ? SearchLyric(new Uri(lyricUrl))
-                : new SearchResult();
+                : new SearchResult(Models.ExternalProviderType.Genius);
         }
 
         #endregion
@@ -105,7 +112,10 @@ protected override async Task<SearchResult> SearchLyricAsync(Uri uri)
         {
             var htmlPageBody = await WebClient.LoadAsync(uri);
 
-            return new SearchResult(GetParsedLyricFromHtmlPageBody(htmlPageBody), Models.ExternalProviderType.Genius);
+            var lyricResult = GetParsedLyricFromHtmlPageBody(htmlPageBody, out var instrumental);
+
+            return new SearchResult(lyricResult, Models.ExternalProviderType.Genius)
+                .AddInstrumental(instrumental);
         }
 
         protected override async Task<SearchResult> SearchLyricAsync(string artist, string song)
@@ -128,11 +138,16 @@ protected override async Task<SearchResult> SearchLyricAsync(string artist, stri
 
             return !string.IsNullOrWhiteSpace(lyricUrl)
                 ? await SearchLyricAsync(new Uri(lyricUrl))
-                : new SearchResult();
+                : new SearchResult(Models.ExternalProviderType.Genius);
         }
 
         #endregion
 
+        public override void WithLogger(ILoggerFactory loggerFactory)
+        {
+            _logger = loggerFactory.CreateLogger<GeniusProvider>();
+        }
+
         private string GetLyricUrlWithoutApiKey(string artist, string song)
         {
             var htmlPageBody = WebClient.Load(_uriConverter.GetLyricUri(artist, song));
@@ -160,8 +175,10 @@ private string GetLyricUrlWithoutApiKey(string artist, string song)
             return string.Empty;
         }
 
-        private string GetParsedLyricFromHtmlPageBody(string htmlPageBody)
+        private string GetParsedLyricFromHtmlPageBody(string htmlPageBody, out bool instrumental)
         {
+            instrumental = false;
+
             var htmlDocument = new HtmlDocument();
             htmlDocument.LoadHtml(htmlPageBody.Replace("https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js", ""));
 
@@ -175,8 +192,20 @@ private string GetParsedLyricFromHtmlPageBody(string htmlPageBody)
                     spanNode.Remove();
 
             var lyricNodes = htmlDocument.DocumentNode.SelectNodes(_lyricsContainerNodesXPath);
+            if (lyricNodes == null)
+            {
+                // lyricNodes could be null in case of instrumental.
+                var instrumentalNodes = htmlDocument.DocumentNode.SelectNodes(_lyricsPlaceholderNodesXPath);
+                if (instrumentalNodes != null 
+                    && instrumentalNodes.Any(node => node.InnerHtml.Contains(_instrumentalLyricText)))
+                {
+                    instrumental = true;
+                    return string.Empty;
+                }
+                _logger?.LogWarning($"Genius. Can't parse lyric from the page.");
+            }
 
-            return Parser.Parse(string.Join("", lyricNodes.Select(Node => Node.InnerHtml)));
+            return Parser.Parse(string.Join("", lyricNodes.Select(node => node.InnerHtml)));
         }
 
         private string GetLyricUrlFromSearchResponse(SearchResponse searchResponse, string artist, string song)

LyricsScraperNET/Providers/LyricFind/LyricFindProvider.cs

@@ -11,7 +11,7 @@ namespace LyricsScraperNET.Providers.LyricFind
 {
     public sealed class LyricFindProvider : ExternalProviderBase
     {
-        private readonly ILogger<LyricFindProvider> _logger;
+        private ILogger<LyricFindProvider> _logger;
         private readonly IExternalUriConverter _uriConverter;
 
         private const string _lyricStart = "\"lyrics\"";
@@ -95,6 +95,11 @@ protected override async Task<SearchResult> SearchLyricAsync(Uri uri)
 
         #endregion
 
+        public override void WithLogger(ILoggerFactory loggerFactory)
+        {
+            _logger = loggerFactory.CreateLogger<LyricFindProvider>();
+        }
+
         private SearchResult PostProcessLyric(Uri uri, string text)
         {
             if (string.IsNullOrEmpty(text))