77 lines
2.8 KiB
C#
77 lines
2.8 KiB
C#
/*
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Copyright 2013 Google Inc
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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using System;
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namespace Google.Apis.Http
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{
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/// <summary>
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/// Indicates if exponential back-off is used automatically on exceptions in a service requests and \ or when 503
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/// responses is returned form the server.
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/// </summary>
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[Flags]
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public enum ExponentialBackOffPolicy
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{
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/// <summary>Exponential back-off is disabled.</summary>
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None = 0,
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/// <summary>Exponential back-off is enabled only for exceptions.</summary>
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Exception = 1,
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/// <summary>Exponential back-off is enabled only for 503 HTTP Status code.</summary>
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UnsuccessfulResponse503 = 2
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}
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/// <summary>
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/// An initializer which adds exponential back-off as exception handler and \ or unsuccessful response handler by
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/// the given <see cref="ExponentialBackOffPolicy"/>.
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/// </summary>
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public class ExponentialBackOffInitializer : IConfigurableHttpClientInitializer
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{
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/// <summary>Gets or sets the used back-off policy.</summary>
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private ExponentialBackOffPolicy Policy { get; set; }
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/// <summary>Gets or sets the back-off handler creation function.</summary>
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private Func<BackOffHandler> CreateBackOff { get; set; }
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/// <summary>
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/// Constructs a new back-off initializer with the given policy and back-off handler create function.
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/// </summary>
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public ExponentialBackOffInitializer(ExponentialBackOffPolicy policy, Func<BackOffHandler> createBackOff)
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{
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Policy = policy;
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CreateBackOff = createBackOff;
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}
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/// <inheritdoc/>
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public void Initialize(ConfigurableHttpClient httpClient)
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{
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var backOff = CreateBackOff();
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// Add exception handler and \ or unsuccessful response handler.
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if ((Policy & ExponentialBackOffPolicy.Exception) == ExponentialBackOffPolicy.Exception)
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{
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httpClient.MessageHandler.AddExceptionHandler(backOff);
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}
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if ((Policy & ExponentialBackOffPolicy.UnsuccessfulResponse503) ==
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ExponentialBackOffPolicy.UnsuccessfulResponse503)
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{
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httpClient.MessageHandler.AddUnsuccessfulResponseHandler(backOff);
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}
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}
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}
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}
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