Add a RateLimitInfo property to Query

MetaBrainz.MusicBrainz/Query.Internals.cs

@@ -532,6 +532,14 @@ private async Task<HttpResponseMessage> PerformRequestAsync(Uri uri, HttpMethod
  Debug.Print($"[{DateTime.UtcNow}] => HEADERS: {TextUtils.FormatMultiLine(response.Headers.ToString())}");
  Debug.Print($"[{DateTime.UtcNow}] => CONTENT ({response.Content.Headers.ContentType}): " +
  $"{response.Content.Headers.ContentLength ?? 0} bytes");
+ var rateLimitInfo = new RateLimitInfo(response.Headers);
+ this._rateLimitLock.EnterWriteLock();
+ try {
+ this._rateLimitInfo = rateLimitInfo;
+ }
+ finally {
+ this._rateLimitLock.ExitWriteLock();
+ }
  if (!response.IsSuccessStatusCode) {
  throw await QueryException.FromResponseAsync(response, cancellationToken).ConfigureAwait(false);
  }

MetaBrainz.MusicBrainz/Query.cs

@@ -2,9 +2,12 @@
 using System.Collections.Generic;
 using System.Net.Http;
 using System.Net.Http.Headers;
+using System.Threading;
 
 using JetBrains.Annotations;
 
+using MetaBrainz.Common;
+
 namespace MetaBrainz.MusicBrainz;
 
 /// <summary>Class providing access to the MusicBrainz API.</summary>
@@ -77,7 +80,8 @@ public static string DefaultUrlScheme {
  /// </summary>
  /// <remarks>
  /// Note that this is a global delay, affecting all threads. When querying the official MusicBrainz site, setting this below the
- /// default of one second may incur penalties (ranging from rate limiting to IP bans).
+ /// default of one second may incur penalties (ranging from rate limiting to IP bans). When setting this to 0 for maximum
+ /// throughput, <see cref="RateLimitInfo"/> can be used to avoid making too many requests and trigger these penalties.
  /// </remarks>
  public static double DelayBetweenRequests { get; set; } = 1.0;
 
@@ -209,6 +213,27 @@ public int Port {
  }
  }
 
+ private RateLimitInfo _rateLimitInfo;
+
+ private readonly ReaderWriterLockSlim _rateLimitLock = new();
+
+ /// <summary>The rate limit information from the last web request issued via this MusicBrainz client.</summary>
+ /// <remarks>
+ /// This is mainly useful when setting <see cref="DelayBetweenRequests"/> to 0, in order to manage the request volume to avoid
+ /// triggering penalties.
+ /// </remarks>
+ public RateLimitInfo RateLimitInfo {
+ get {
+ this._rateLimitLock.EnterReadLock();
+ try {
+ return this._rateLimitInfo;
+ }
+ finally {
+ this._rateLimitLock.ExitReadLock();
+ }
+ }
+ }
+
  private string _server = Query.DefaultServer;
 
  /// <summary>The web site to use for requests.</summary>