Upgrade to Polly 8 usage

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -33,7 +33,7 @@ public class DiscordClient
         CancellationToken cancellationToken = default
     )
     {
-        return await Http.ResponseResiliencePolicy.ExecuteAsync(
+        return await Http.ResponseResiliencePipeline.ExecuteAsync(
             async innerCancellationToken =>
             {
                 using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));

DiscordChatExporter.Core/Exporting/ExportAssetDownloader.cs

@@ -53,12 +53,13 @@ internal partial class ExportAssetDownloader
 
         Directory.CreateDirectory(_workingDirPath);
 
-        await Http.ResiliencePolicy.ExecuteAsync(async () =>
+        await Http.ResiliencePipeline.ExecuteAsync(
+            async innerCancellationToken =>
             {
                 // Download the file
-            using var response = await Http.Client.GetAsync(url, cancellationToken);
+                using var response = await Http.Client.GetAsync(url, innerCancellationToken);
                 await using (var output = File.Create(filePath))
-                await response.Content.CopyToAsync(output, cancellationToken);
+                    await response.Content.CopyToAsync(output, innerCancellationToken);
 
                 // Try to set the file date according to the last-modified header
                 try
@@ -90,7 +91,9 @@ internal partial class ExportAssetDownloader
                     // Updating the file date is not a critical task, so we'll just ignore exceptions thrown here.
                     // https://github.com/Tyrrrz/DiscordChatExporter/issues/585
                 }
-        });
+            },
+            cancellationToken
+        );
 
         return _previousPathsByUrl[url] = filePath;
     }

DiscordChatExporter.Core/Utils/Http.cs

@@ -7,6 +7,7 @@ using System.Security.Authentication;
 using System.Threading.Tasks;
 using DiscordChatExporter.Core.Utils.Extensions;
 using Polly;
+using Polly.Retry;
 
 namespace DiscordChatExporter.Core.Utils;
 
@@ -31,29 +32,45 @@ public static class Http
                         && IsRetryableStatusCode(hrex.StatusCode ?? HttpStatusCode.OK)
             );
 
-    public static IAsyncPolicy ResiliencePolicy { get; } =
-        Policy
-            .Handle<Exception>(IsRetryableException)
-            .WaitAndRetryAsync(4, i => TimeSpan.FromSeconds(Math.Pow(2, i) + 1));
+    public static ResiliencePipeline ResiliencePipeline { get; } =
+        new ResiliencePipelineBuilder()
+            .AddRetry(
+                new RetryStrategyOptions
+                {
+                    ShouldHandle = new PredicateBuilder().Handle<Exception>(IsRetryableException),
+                    MaxRetryAttempts = 4,
+                    BackoffType = DelayBackoffType.Exponential,
+                    Delay = TimeSpan.FromSeconds(1)
+                }
+            )
+            .Build();
 
-    public static IAsyncPolicy<HttpResponseMessage> ResponseResiliencePolicy { get; } =
-        Policy
+    public static ResiliencePipeline<HttpResponseMessage> ResponseResiliencePipeline { get; } =
+        new ResiliencePipelineBuilder<HttpResponseMessage>()
+            .AddRetry(
+                new RetryStrategyOptions<HttpResponseMessage>
+                {
+                    ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
                         .Handle<Exception>(IsRetryableException)
-            .OrResult<HttpResponseMessage>(m => IsRetryableStatusCode(m.StatusCode))
-            .WaitAndRetryAsync(
-                8,
-                (i, result, _) =>
+                        .HandleResult(m => IsRetryableStatusCode(m.StatusCode)),
+                    MaxRetryAttempts = 8,
+                    DelayGenerator = args =>
                     {
                         // If rate-limited, use retry-after header as the guide.
                         // The response can be null here if an exception was thrown.
-                    if (result.Result?.Headers.RetryAfter?.Delta is { } retryAfter)
+                        if (args.Outcome.Result?.Headers.RetryAfter?.Delta is { } retryAfter)
                         {
                             // Add some buffer just in case
-                        return retryAfter + TimeSpan.FromSeconds(1);
+                            return ValueTask.FromResult<TimeSpan?>(
+                                retryAfter + TimeSpan.FromSeconds(1)
+                            );
                         }
 
-                    return TimeSpan.FromSeconds(Math.Pow(2, i) + 1);
-                },
-                (_, _, _, _) => Task.CompletedTask
+                        return ValueTask.FromResult<TimeSpan?>(
+                            TimeSpan.FromSeconds(Math.Pow(2, args.AttemptNumber) + 1)
                         );
+                    }
+                }
+            )
+            .Build();
 }