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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Shared.Diagnostics;
using Polly;
namespace Microsoft.Extensions.Http.Resilience.Internal;
/// <summary>
/// This strategy creates a snapshot of <see cref="HttpRequestMessage"/> before executing the hedging to prevent race conditions when cloning and modifying the message at the same time.
/// This way, all hedged requests will have an unique instance of the message available from snapshot without the need to access the original one for cloning.
/// </summary>
internal sealed class RequestMessageSnapshotStrategy : ResilienceStrategy
{
protected override async ValueTask<Outcome<TResult>> ExecuteCore<TResult, TState>(
Func<ResilienceContext, TState, ValueTask<Outcome<TResult>>> callback,
ResilienceContext context,
TState state)
{
HttpRequestMessage? request = context.GetRequestMessage();
if (request is null)
{
Throw.InvalidOperationException("The HTTP request message was not found in the resilience context.");
}
using var snapshot = RequestMessageSnapshot.Create(request);
context.Properties.Set(ResilienceKeys.RequestSnapshot, snapshot);
return await callback(context, state).ConfigureAwait(context.ContinueOnCapturedContext);
}
}
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