root / trunk / Pithos.Network / RestClient.cs @ 3c76f045
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// ----------------------------------------------------------------------- |
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// <copyright file="RestClient.cs" company="GRNet"> |
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// Copyright 2011 GRNET S.A. All rights reserved. |
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// |
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// Redistribution and use in source and binary forms, with or |
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// without modification, are permitted provided that the following |
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// conditions are met: |
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// |
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// 1. Redistributions of source code must retain the above |
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// copyright notice, this list of conditions and the following |
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// disclaimer. |
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// |
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// 2. Redistributions in binary form must reproduce the above |
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// copyright notice, this list of conditions and the following |
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// disclaimer in the documentation and/or other materials |
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// provided with the distribution. |
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// |
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// THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS |
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// OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR |
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// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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// USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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// POSSIBILITY OF SUCH DAMAGE. |
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// |
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// The views and conclusions contained in the software and |
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// documentation are those of the authors and should not be |
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// interpreted as representing official policies, either expressed |
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// or implied, of GRNET S.A. |
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// </copyright> |
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// ----------------------------------------------------------------------- |
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|
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using System.Collections.Specialized; |
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using System.Diagnostics; |
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using System.Diagnostics.Contracts; |
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using System.IO; |
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using System.Net; |
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using System.Runtime.Serialization; |
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using System.Threading.Tasks; |
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using log4net; |
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|
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|
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namespace Pithos.Network |
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{ |
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using System; |
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using System.Collections.Generic; |
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using System.Linq; |
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using System.Text; |
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|
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/// <summary> |
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/// TODO: Update summary. |
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/// </summary> |
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public class RestClient:WebClient |
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{ |
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public int Timeout { get; set; } |
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|
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public bool TimedOut { get; set; } |
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|
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public HttpStatusCode StatusCode { get; private set; } |
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|
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public string StatusDescription { get; set; } |
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|
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public long? RangeFrom { get; set; } |
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public long? RangeTo { get; set; } |
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|
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public int Retries { get; set; } |
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|
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private readonly Dictionary<string, string> _parameters=new Dictionary<string, string>(); |
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public Dictionary<string, string> Parameters |
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{ |
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get |
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{ |
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Contract.Ensures(_parameters!=null); |
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return _parameters; |
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} |
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} |
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|
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private static readonly ILog Log = LogManager.GetLogger("RestClient"); |
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|
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|
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[ContractInvariantMethod] |
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private void Invariants() |
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{ |
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Contract.Invariant(Headers!=null); |
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} |
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|
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public RestClient():base() |
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{ |
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|
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} |
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|
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|
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public RestClient(RestClient other) |
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: base() |
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{ |
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if (other==null) |
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throw new ArgumentNullException("other"); |
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Contract.EndContractBlock(); |
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|
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CopyHeaders(other); |
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Timeout = other.Timeout; |
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Retries = other.Retries; |
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BaseAddress = other.BaseAddress; |
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|
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foreach (var parameter in other.Parameters) |
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{ |
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Parameters.Add(parameter.Key,parameter.Value); |
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} |
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|
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this.Proxy = other.Proxy; |
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} |
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|
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|
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protected override WebRequest GetWebRequest(Uri address) |
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{ |
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TimedOut = false; |
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var webRequest = base.GetWebRequest(address); |
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var request = (HttpWebRequest)webRequest; |
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request.ServicePoint.ConnectionLimit = 10; |
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if (IfModifiedSince.HasValue) |
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request.IfModifiedSince = IfModifiedSince.Value; |
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request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip; |
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if(Timeout>0) |
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request.Timeout = Timeout; |
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|
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if (RangeFrom.HasValue) |
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{ |
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if (RangeTo.HasValue) |
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request.AddRange(RangeFrom.Value, RangeTo.Value); |
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else |
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request.AddRange(RangeFrom.Value); |
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} |
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return request; |
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} |
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|
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public DateTime? IfModifiedSince { get; set; } |
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|
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//Asynchronous version |
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protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result) |
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{ |
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Log.InfoFormat("ASYNC [{0}] {1}",request.Method, request.RequestUri); |
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HttpWebResponse response = null; |
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|
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try |
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{ |
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response = (HttpWebResponse)base.GetWebResponse(request, result); |
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} |
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catch (WebException exc) |
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{ |
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if (!TryGetResponse(exc, out response)) |
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throw; |
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} |
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|
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StatusCode = response.StatusCode; |
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LastModified = response.LastModified; |
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StatusDescription = response.StatusDescription; |
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return response; |
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|
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} |
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|
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|
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//Synchronous version |
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protected override WebResponse GetWebResponse(WebRequest request) |
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{ |
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HttpWebResponse response = null; |
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try |
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{ |
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response = (HttpWebResponse)base.GetWebResponse(request); |
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} |
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catch (WebException exc) |
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{ |
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if (!TryGetResponse(exc, out response)) |
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throw; |
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} |
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|
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StatusCode = response.StatusCode; |
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LastModified = response.LastModified; |
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StatusDescription = response.StatusDescription; |
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return response; |
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} |
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|
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private bool TryGetResponse(WebException exc, out HttpWebResponse response) |
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{ |
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response = null; |
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//Fail on empty response |
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if (exc.Response == null) |
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return false; |
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|
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response = (exc.Response as HttpWebResponse); |
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//Succeed on allowed status codes |
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if (AllowedStatusCodes.Contains(response.StatusCode)) |
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return true; |
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|
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//Does the response have any content to log? |
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if (exc.Response.ContentLength > 0) |
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{ |
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var content = LogContent(exc.Response); |
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Log.ErrorFormat(content); |
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} |
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return false; |
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} |
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|
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private readonly List<HttpStatusCode> _allowedStatusCodes=new List<HttpStatusCode>{HttpStatusCode.NotModified}; |
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|
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public List<HttpStatusCode> AllowedStatusCodes |
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{ |
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get |
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{ |
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return _allowedStatusCodes; |
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} |
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} |
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|
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public DateTime LastModified { get; private set; } |
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|
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private static string LogContent(WebResponse webResponse) |
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{ |
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if (webResponse == null) |
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throw new ArgumentNullException("webResponse"); |
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Contract.EndContractBlock(); |
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|
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//The response stream must be copied to avoid affecting other code by disposing of the |
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//original response stream. |
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var stream = webResponse.GetResponseStream(); |
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using(var memStream=new MemoryStream()) |
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using (var reader = new StreamReader(memStream)) |
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{ |
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stream.CopyTo(memStream); |
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string content = reader.ReadToEnd(); |
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|
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stream.Seek(0,SeekOrigin.Begin); |
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return content; |
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} |
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} |
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|
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public string DownloadStringWithRetry(string address,int retries=0) |
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{ |
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|
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if (address == null) |
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throw new ArgumentNullException("address"); |
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|
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var actualAddress = GetActualAddress(address); |
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|
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TraceStart("GET",actualAddress); |
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|
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var actualRetries = (retries == 0) ? Retries : retries; |
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|
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var uriString = String.Join("/", BaseAddress.TrimEnd('/'), actualAddress); |
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|
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var task = Retry(() => |
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{ |
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var content = base.DownloadString(uriString); |
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|
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if (StatusCode == HttpStatusCode.NoContent) |
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return String.Empty; |
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return content; |
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|
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}, actualRetries); |
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|
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var result = task.Result; |
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return result; |
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} |
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|
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public void Head(string address,int retries=0) |
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{ |
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AllowedStatusCodes.Add(HttpStatusCode.NotFound); |
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RetryWithoutContent(address, retries, "HEAD"); |
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} |
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|
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public void PutWithRetry(string address, int retries = 0) |
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{ |
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RetryWithoutContent(address, retries, "PUT"); |
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} |
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|
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public void DeleteWithRetry(string address,int retries=0) |
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{ |
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RetryWithoutContent(address, retries, "DELETE"); |
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} |
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|
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public string GetHeaderValue(string headerName,bool optional=false) |
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{ |
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if (this.ResponseHeaders==null) |
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throw new InvalidOperationException("ResponseHeaders are null"); |
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Contract.EndContractBlock(); |
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|
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var values=this.ResponseHeaders.GetValues(headerName); |
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if (values != null) |
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return values[0]; |
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|
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if (optional) |
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return null; |
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//A required header was not found |
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throw new WebException(String.Format("The {0} header is missing", headerName)); |
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} |
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|
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public void SetNonEmptyHeaderValue(string headerName, string value) |
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{ |
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if (String.IsNullOrWhiteSpace(value)) |
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return; |
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Headers.Add(headerName,value); |
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} |
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|
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private void RetryWithoutContent(string address, int retries, string method) |
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{ |
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if (address == null) |
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throw new ArgumentNullException("address"); |
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|
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var actualAddress = GetActualAddress(address); |
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var actualRetries = (retries == 0) ? Retries : retries; |
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|
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var task = Retry(() => |
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{ |
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var uriString = String.Join("/",BaseAddress ,actualAddress); |
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var uri = new Uri(uriString); |
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var request = GetWebRequest(uri); |
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request.Method = method; |
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if (ResponseHeaders!=null) |
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ResponseHeaders.Clear(); |
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|
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TraceStart(method, uriString); |
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if (method == "PUT") |
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request.ContentLength = 0; |
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|
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//Have to use try/finally instead of using here, because WebClient needs a valid WebResponse object |
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//in order to return response headers |
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var response = (HttpWebResponse)GetWebResponse(request); |
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try |
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{ |
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LastModified = response.LastModified; |
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StatusCode = response.StatusCode; |
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StatusDescription = response.StatusDescription; |
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} |
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finally |
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{ |
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response.Close(); |
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} |
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|
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|
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return 0; |
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}, actualRetries); |
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|
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try |
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{ |
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task.Wait(); |
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} |
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catch (AggregateException ex) |
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{ |
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var exc = ex.InnerException; |
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if (exc is RetryException) |
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{ |
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Log.ErrorFormat("[{0}] RETRY FAILED for {1} after {2} retries",method,address,retries); |
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} |
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else |
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{ |
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Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, exc); |
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} |
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throw exc; |
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|
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} |
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catch(Exception ex) |
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{ |
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Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, ex); |
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throw; |
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} |
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} |
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|
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private static void TraceStart(string method, string actualAddress) |
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{ |
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Log.InfoFormat("[{0}] {1} {2}", method, DateTime.Now, actualAddress); |
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} |
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|
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private string GetActualAddress(string address) |
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{ |
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if (Parameters.Count == 0) |
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return address; |
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var addressBuilder=new StringBuilder(address); |
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|
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bool isFirst = true; |
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foreach (var parameter in Parameters) |
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{ |
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if(isFirst) |
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addressBuilder.AppendFormat("?{0}={1}", parameter.Key, parameter.Value); |
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else |
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addressBuilder.AppendFormat("&{0}={1}", parameter.Key, parameter.Value); |
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isFirst = false; |
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} |
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return addressBuilder.ToString(); |
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} |
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|
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public string DownloadStringWithRetry(Uri address,int retries=0) |
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{ |
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if (address == null) |
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throw new ArgumentNullException("address"); |
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|
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var actualRetries = (retries == 0) ? Retries : retries; |
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var task = Retry(() => |
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{ |
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var content = base.DownloadString(address); |
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|
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if (StatusCode == HttpStatusCode.NoContent) |
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return String.Empty; |
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return content; |
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|
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}, actualRetries); |
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|
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var result = task.Result; |
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return result; |
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} |
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|
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|
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/// <summary> |
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/// Copies headers from another RestClient |
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/// </summary> |
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/// <param name="source">The RestClient from which the headers are copied</param> |
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public void CopyHeaders(RestClient source) |
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{ |
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if (source == null) |
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throw new ArgumentNullException("source", "source can't be null"); |
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Contract.EndContractBlock(); |
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//The Headers getter initializes the property, it is never null |
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Contract.Assume(Headers!=null); |
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|
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CopyHeaders(source.Headers,Headers); |
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} |
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|
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/// <summary> |
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/// Copies headers from one header collection to another |
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/// </summary> |
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/// <param name="source">The source collection from which the headers are copied</param> |
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/// <param name="target">The target collection to which the headers are copied</param> |
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public static void CopyHeaders(WebHeaderCollection source,WebHeaderCollection target) |
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{ |
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if (source == null) |
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throw new ArgumentNullException("source", "source can't be null"); |
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if (target == null) |
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throw new ArgumentNullException("target", "target can't be null"); |
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Contract.EndContractBlock(); |
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|
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for (int i = 0; i < source.Count; i++) |
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{ |
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target.Add(source.GetKey(i), source[i]); |
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} |
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} |
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|
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public void AssertStatusOK(string message) |
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{ |
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if (StatusCode >= HttpStatusCode.BadRequest) |
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throw new WebException(String.Format("{0} with code {1} - {2}", message, StatusCode, StatusDescription)); |
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} |
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|
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|
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private Task<T> Retry<T>(Func<T> original, int retryCount, TaskCompletionSource<T> tcs = null) |
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{ |
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if (original==null) |
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throw new ArgumentNullException("original"); |
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Contract.EndContractBlock(); |
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|
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if (tcs == null) |
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tcs = new TaskCompletionSource<T>(); |
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Task.Factory.StartNew(original).ContinueWith(_original => |
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{ |
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if (!_original.IsFaulted) |
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tcs.SetFromTask(_original); |
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else |
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{ |
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var e = _original.Exception.InnerException; |
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var we = (e as WebException); |
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if (we==null) |
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tcs.SetException(e); |
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else |
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{ |
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var statusCode = GetStatusCode(we); |
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|
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//Return null for 404 |
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if (statusCode == HttpStatusCode.NotFound) |
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tcs.SetResult(default(T)); |
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//Retry for timeouts and service unavailable |
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else if (we.Status == WebExceptionStatus.Timeout || |
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(we.Status == WebExceptionStatus.ProtocolError && statusCode == HttpStatusCode.ServiceUnavailable)) |
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{ |
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TimedOut = true; |
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if (retryCount == 0) |
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{ |
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Log.ErrorFormat("[ERROR] Timed out too many times. \n{0}\n",e); |
489 |
tcs.SetException(new RetryException("Timed out too many times.", e)); |
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} |
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else |
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{ |
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Log.ErrorFormat( |
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"[RETRY] Timed out after {0} ms. Will retry {1} more times\n{2}", Timeout, |
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retryCount, e); |
496 |
Retry(original, retryCount - 1, tcs); |
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} |
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} |
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else |
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tcs.SetException(e); |
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} |
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}; |
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}); |
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return tcs.Task; |
505 |
} |
506 |
|
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private HttpStatusCode GetStatusCode(WebException we) |
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{ |
509 |
if (we==null) |
510 |
throw new ArgumentNullException("we"); |
511 |
var statusCode = HttpStatusCode.RequestTimeout; |
512 |
if (we.Response != null) |
513 |
{ |
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statusCode = ((HttpWebResponse) we.Response).StatusCode; |
515 |
this.StatusCode = statusCode; |
516 |
} |
517 |
return statusCode; |
518 |
} |
519 |
|
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public UriBuilder GetAddressBuilder(string container, string objectName) |
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{ |
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var builder = new UriBuilder(String.Join("/", BaseAddress, container, objectName)); |
523 |
return builder; |
524 |
} |
525 |
|
526 |
public Dictionary<string, string> GetMeta(string metaPrefix) |
527 |
{ |
528 |
if (String.IsNullOrWhiteSpace(metaPrefix)) |
529 |
throw new ArgumentNullException("metaPrefix"); |
530 |
Contract.EndContractBlock(); |
531 |
|
532 |
var keys = ResponseHeaders.AllKeys.AsQueryable(); |
533 |
var dict = (from key in keys |
534 |
where key.StartsWith(metaPrefix) |
535 |
let name = key.Substring(metaPrefix.Length) |
536 |
select new { Name = name, Value = ResponseHeaders[key] }) |
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.ToDictionary(t => t.Name, t => t.Value); |
538 |
return dict; |
539 |
} |
540 |
} |
541 |
|
542 |
public class RetryException:Exception |
543 |
{ |
544 |
public RetryException() |
545 |
:base() |
546 |
{ |
547 |
|
548 |
} |
549 |
|
550 |
public RetryException(string message) |
551 |
:base(message) |
552 |
{ |
553 |
|
554 |
} |
555 |
|
556 |
public RetryException(string message,Exception innerException) |
557 |
:base(message,innerException) |
558 |
{ |
559 |
|
560 |
} |
561 |
|
562 |
public RetryException(SerializationInfo info,StreamingContext context) |
563 |
:base(info,context) |
564 |
{ |
565 |
|
566 |
} |
567 |
} |
568 |
} |