问题描述
我有一个返回HttpResponseMessage的WebAPI控制器，我想添加gzip压缩.这是服务器代码:
using System.Net.Http;
using System.Web.Http;
using System.Web;
using System.IO.Compression;
[Route("SomeRoute")]
public HttpResponseMessage Post([FromBody] string value)
{
HttpContext context = HttpContext.Current;
context.Response.Filter = new GZipStream(context.Response.Filter, CompressionMode.Compress);
HttpContext.Current.Response.AppendHeader("Content-encoding", "gzip");
HttpContext.Current.Response.Cache.VaryByHeaders["Accept-encoding"] = true;
return new SomeClass().SomeRequest(value);
}
这是使用jquery进行ajax调用的客户端代码:
$.ajax({
url: "/SomeRoute",
type: "POST",
cache: "false",
data: SomeData,
beforeSend: function (jqXHR) { jqXHR.setRequestHeader('Accept-Encoding', 'gzip'); },
success: function(msg) { ... }
当我运行此代码时，服务器代码返回时没有错误，但客户端错误:
(failed)
net::ERR_CONTENT_DECODING_FAILED
当我看着Fiddler时，这就是我所看到的:
我需要更改什么以使Web服务返回客户端正常处理的压缩内容?我知道我也可以使用HttpModule或通过IIS上的某些设置来执行此操作，但是这两个选项都不适合托管的情况:
请注意，我并不是在寻找IIS设置，因为我无权访问该设置(托管).
如果您有权访问IIS配置
您不能仅应用标头并希望将其压缩-响应将不会被压缩.
您需要删除添加的标头，并确保在IIS服务器上启用了动态压缩和静态内容压缩.
其中一位评论者在stakoverflow上提到了一个很好的资源链接，展示了如何做到这一点:
请注意，只有在已经安装了动态压缩(不是在IIS的默认安装中)的情况下，它才可以在web.config中设置该值.
您可以在MSDN文档中找到有关此信息: http://www.iis .net/configreference/system.webserver/httpcompression
简单压缩
下面使用一个简单的示例进行自己的压缩，该示例使用Visual Studio项目模板中的Web Api MVC 4项目.为了使压缩适用于HttpResponseMessages，您必须实现自定义MessageHandler.参见下面的工作示例.
请参见下面的代码实现.
请注意，我尝试使该方法的功能与您的示例相同.
using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;
namespace MvcApplication1.Controllers
{
public class ValuesController : ApiController
{
public class Person
{
public string name { get; set; }
}
// GET api/values
public IEnumerable<string> Get()
{
HttpContext.Current.Response.Cache.VaryByHeaders["accept-encoding"] = true;
return new [] { "value1", "value2" };
}
// GET api/values/5
public HttpResponseMessage Get(int id)
{
HttpContext.Current.Response.Cache.VaryByHeaders["accept-encoding"] = true;
var TheHTTPResponse = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
TheHTTPResponse.Content = new StringContent("{\"asdasdasdsadsad\": 123123123 }", Encoding.UTF8, "text/json");
return TheHTTPResponse;
}
public class EncodingDelegateHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
return base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>((responseToCompleteTask) =>
{
HttpResponseMessage response = responseToCompleteTask.Result;
if (response.RequestMessage.Headers.AcceptEncoding != null &&
response.RequestMessage.Headers.AcceptEncoding.Count > 0)
{
string encodingType = response.RequestMessage.Headers.AcceptEncoding.First().Value;
response.Content = new CompressedContent(response.Content, encodingType);
}
return response;
},
TaskContinuationOptions.OnlyOnRanToCompletion);
}
}
public class CompressedContent : HttpContent
{
private HttpContent originalContent;
private string encodingType;
public CompressedContent(HttpContent content, string encodingType)
{
if (content == null)
{
throw new ArgumentNullException("content");
}
if (encodingType == null)
{
throw new ArgumentNullException("encodingType");
}
originalContent = content;
this.encodingType = encodingType.ToLowerInvariant();
if (this.encodingType != "gzip" && this.encodingType != "deflate")
{
throw new InvalidOperationException(string.Format("Encoding '{0}' is not supported. Only supports gzip or deflate encoding.", this.encodingType));
}
// copy the headers from the original content
foreach (KeyValuePair<string, IEnumerable<string>> header in originalContent.Headers)
{
this.Headers.TryAddWithoutValidation(header.Key, header.Value);
}
this.Headers.ContentEncoding.Add(encodingType);
}
protected override bool TryComputeLength(out long length)
{
length = -1;
return false;
}
protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
Stream compressedStream = null;
if (encodingType == "gzip")
{
compressedStream = new GZipStream(stream, CompressionMode.Compress, leaveOpen: true);
}
else if (encodingType == "deflate")
{
compressedStream = new DeflateStream(stream, CompressionMode.Compress, leaveOpen: true);
}
return originalContent.CopyToAsync(compressedStream).ContinueWith(tsk =>
{
if (compressedStream != null)
{
compressedStream.Dispose();
}
});
}
}
}
}
还将新的消息处理程序添加到应用程序的配置中.
using System.Web.Http;
using MvcApplication1.Controllers;
namespace MvcApplication1
{
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
config.MessageHandlers.Add(new ValuesController.EncodingDelegateHandler());
config.EnableSystemDiagnosticsTracing();
}
}
}
自定义处理程序由-Kiran Challa( http://blogs.msdn.com/b/kiranchalla/archive/2012/09/04/handling-compression-accept-encoding-sample.aspx )
还有一些更好的示例可以对入站流进行压缩，您也可以在下面看到示例:
- http://www.codeproject. com/Articles/557232/在ASP.NET中实现自定义DelegatingHandler
- http://ronaldrosiernet.azurewebsites.net/blog/2013/07/16/implement_compression_in_aspnet_web_api
此外，我在github上找到了一个非常不错的项目来支持所有这些项目.
请注意，当我本人亲自到达此答案时，西蒙(Simon)在您的答案的两天前就建议采用这种方法.
I have a WebAPI controller that returns an HttpResponseMessage and I want to add gzip compression. This is the server code:
using System.Net.Http;
using System.Web.Http;
using System.Web;
using System.IO.Compression;
[Route("SomeRoute")]
public HttpResponseMessage Post([FromBody] string value)
{
HttpContext context = HttpContext.Current;
context.Response.Filter = new GZipStream(context.Response.Filter, CompressionMode.Compress);
HttpContext.Current.Response.AppendHeader("Content-encoding", "gzip");
HttpContext.Current.Response.Cache.VaryByHeaders["Accept-encoding"] = true;
return new SomeClass().SomeRequest(value);
}
And this is the client code for the ajax call, using jquery:
$.ajax({
url: "/SomeRoute",
type: "POST",
cache: "false",
data: SomeData,
beforeSend: function (jqXHR) { jqXHR.setRequestHeader('Accept-Encoding', 'gzip'); },
success: function(msg) { ... }
When I run this, the server code returns without bugging but the client bugs:
(failed)
net::ERR_CONTENT_DECODING_FAILED
When I look with Fiddler, this is what I see:
What do I need to change to make the web service return gzipped content that the client processes normally? I know I could also do this with an HttpModule or through some setting on IIS but neither option fits the scenario of the hosting:
Please note that I'm not looking for an IIS setting because I don't have access to that (hosting).
If you have access to IIS configuration
You cant just apply the header and hope it will be gzipped - the response will not be zipped.
You need remove the header you added and ensure you have the dynamic compression and static content compression are enabled on your IIS server.
One of the commenter's mentioned a good resource link here at stakoverflow that show how to do that:
Note it will only work setting the value in web.config if dynamic compression is already installed (which is not in a default install of IIS)
You can find the information about this on MSDN documentation: http://www.iis.net/configreference/system.webserver/httpcompression
Simple compression
Below is using a simple example of doing your own compression this example is using the Web Api MVC 4 project from visual studio project templates. To get compression working for HttpResponseMessages you have to implement a custom MessageHandler. See below a working example.
See the code implementation below.
Please note that I tried to keep the method doing the same as your example.
using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;
namespace MvcApplication1.Controllers
{
public class ValuesController : ApiController
{
public class Person
{
public string name { get; set; }
}
// GET api/values
public IEnumerable<string> Get()
{
HttpContext.Current.Response.Cache.VaryByHeaders["accept-encoding"] = true;
return new [] { "value1", "value2" };
}
// GET api/values/5
public HttpResponseMessage Get(int id)
{
HttpContext.Current.Response.Cache.VaryByHeaders["accept-encoding"] = true;
var TheHTTPResponse = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
TheHTTPResponse.Content = new StringContent("{\"asdasdasdsadsad\": 123123123 }", Encoding.UTF8, "text/json");
return TheHTTPResponse;
}
public class EncodingDelegateHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
return base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>((responseToCompleteTask) =>
{
HttpResponseMessage response = responseToCompleteTask.Result;
if (response.RequestMessage.Headers.AcceptEncoding != null &&
response.RequestMessage.Headers.AcceptEncoding.Count > 0)
{
string encodingType = response.RequestMessage.Headers.AcceptEncoding.First().Value;
response.Content = new CompressedContent(response.Content, encodingType);
}
return response;
},
TaskContinuationOptions.OnlyOnRanToCompletion);
}
}
public class CompressedContent : HttpContent
{
private HttpContent originalContent;
private string encodingType;
public CompressedContent(HttpContent content, string encodingType)
{
if (content == null)
{
throw new ArgumentNullException("content");
}
if (encodingType == null)
{
throw new ArgumentNullException("encodingType");
}
originalContent = content;
this.encodingType = encodingType.ToLowerInvariant();
if (this.encodingType != "gzip" && this.encodingType != "deflate")
{
throw new InvalidOperationException(string.Format("Encoding '{0}' is not supported. Only supports gzip or deflate encoding.", this.encodingType));
}
// copy the headers from the original content
foreach (KeyValuePair<string, IEnumerable<string>> header in originalContent.Headers)
{
this.Headers.TryAddWithoutValidation(header.Key, header.Value);
}
this.Headers.ContentEncoding.Add(encodingType);
}
protected override bool TryComputeLength(out long length)
{
length = -1;
return false;
}
protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
Stream compressedStream = null;
if (encodingType == "gzip")
{
compressedStream = new GZipStream(stream, CompressionMode.Compress, leaveOpen: true);
}
else if (encodingType == "deflate")
{
compressedStream = new DeflateStream(stream, CompressionMode.Compress, leaveOpen: true);
}
return originalContent.CopyToAsync(compressedStream).ContinueWith(tsk =>
{
if (compressedStream != null)
{
compressedStream.Dispose();
}
});
}
}
}
}
Also add the new message handler to the config of your app.
using System.Web.Http;
using MvcApplication1.Controllers;
namespace MvcApplication1
{
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
config.MessageHandlers.Add(new ValuesController.EncodingDelegateHandler());
config.EnableSystemDiagnosticsTracing();
}
}
}
The Custom handler was put together by - Kiran Challa (http://blogs.msdn.com/b/kiranchalla/archive/2012/09/04/handling-compression-accept-encoding-sample.aspx)
There are better examples that implement deflating of inbound streams too you can see examples of that below:
- http://www.codeproject.com/Articles/557232/Implementing-a-Custom-DelegatingHandler-in-ASP-NET
- http://ronaldrosiernet.azurewebsites.net/blog/2013/07/16/implement_compression_in_aspnet_web_api
Additionally I found a really nice project that supports all of this on github.
Note while I arrived to this answer by myself Simon in your comments suggested this approach 2 days ago from the date of this answer.
这篇关于返回HttpResponseMessage时的WebAPI Gzip的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！