难以使用WCF上传大文件

在SO上还有很多类似的问题。不幸的是，许多人似乎在某些方面互相欺骗。我希望这篇文章能帮助别人，并解决其他问题。

我的项目要求是通过IIS上传250MB的文件到IIS托管的后端WCF服务。我为托管在IIS中的后端WCF服务创建了一些单元测试。它们是:

1) Upload 1MB File
2) Upload 5MB File
3) Upload 10MB file
4) Upload 20MB File
5) Upload 200MB File

马上，很明显我们需要使用某种流或分块文件传输。我使用了这个示例。

示例描述了一个使用。net Stream对象的方法。使用流对象的副作用是必须使用Message契约。将Stream放在函数的参数列表中是不够的。所以我们这样做。

默认为web。这个WCF服务的配置非常精简。

System.ServiceModel.ProtocolException: The remote server returned an unexpected response: (400) Bad Request. ---> System.Net.WebException: The remote server returned an error: (400) Bad Request.

经过大量的搜索和实验，很明显，BasicHttpBinding与流对象和MessageContract的这种组合是不兼容的。我们必须切换到WSHttpBinding

要做到这一点，服务器的web。

部分下的配置稍微复杂一些:

<system.serviceModel>
        <behaviors>
            <serviceBehaviors>
                <behavior>
                    <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
                    <serviceMetadata httpGetEnabled="true"/>
                    <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
                    <serviceDebug includeExceptionDetailInFaults="true" httpHelpPageEnabled="true"/>
                </behavior>
                <behavior name="FileServiceBehavior">
                    <serviceMetadata httpGetEnabled="true"/>
                    <dataContractSerializer maxItemsInObjectGraph="2147483647"/>
                    <serviceDebug includeExceptionDetailInFaults="true"/>
                    <serviceThrottling maxConcurrentCalls="500" maxConcurrentSessions="500" maxConcurrentInstances="500"/>
                </behavior>
            </serviceBehaviors>
        </behaviors>
        <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
        <bindings>
            <wsHttpBinding>
                <binding name="FileServiceBinding" closeTimeout="10:01:00"
                  maxBufferPoolSize="104857600"
                  maxReceivedMessageSize="104857600" openTimeout="10:01:00"
                  receiveTimeout="10:10:00" sendTimeout="10:01:00"
                  messageEncoding="Mtom">
                    <readerQuotas maxDepth="104857600" maxStringContentLength="104857600"
                                  maxArrayLength="104857600" maxBytesPerRead="104857600"
                                  maxNameTableCharCount="104857600" />
                </binding>
            </wsHttpBinding>
        </bindings>
        <services>
            <service behaviorConfiguration="FileServiceBehavior" name="OMS.Service.FileService">
                <endpoint address="" binding="wsHttpBinding" bindingConfiguration="FileServiceBinding" contract="OMS.Service.IFileService"></endpoint>
            </service>
        </services>
    </system.serviceModel>

不需要更多的工作，1MB的文件现在通过没有问题。

为了让大于4MB的文件通过，你必须调整web中的设置。这篇来自微软的文章解释了这个设置是什么。例如，如果您将其设置为8192，那么您将能够上传5MB的文件，但不能上传更大的文件。

<httpRuntime maxRequestLength="8192" />

我设置了一些淫秽的测试- 2147483647。前4个文件通过此门。

200MB没有机会到达这个门，原因如下:

System.InsufficientMemoryException: Failed to allocate a managed memory buffer of 279620368 bytes. The amount of available memory may be low. ---> System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.

这张海报对这个问题的解释描述得很好。

这样想。200MB的文件从未从客户端发出。它必须由客户端完全加载，加密，然后传输到服务器。

当你使用Visual Studio 2010为服务生成代理类时，它会把一些东西放入你的app.config中。对我来说，它看起来像这样:

<binding 
 name="Binding_IFileService" closeTimeout="00:01:00"
 openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
 bypassProxyOnLocal="false" transactionFlow="false" 
 hostNameComparisonMode="StrongWildcard"
 maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Mtom"
 textEncoding="utf-8" useDefaultWebProxy="true" allowCookies="false">
    <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
     maxBytesPerRead="4096" maxNameTableCharCount="16384" />
    <reliableSession ordered="true" inactivityTimeout="00:10:00"
         enabled="false" />
    <security mode="Message">
        <transport clientCredentialType="Windows" proxyCredentialType="None" realm="" />
        <message clientCredentialType="Windows" negotiateServiceCredential="true" />
    </security>
</binding>

密钥为安全模式。默认设置为"message"。该值由服务器上设置的任何内容获取。默认情况下，您的服务器正在使用消息级安全性。

如果你试图在服务器上强制它像这样:

 <security mode="None">

你会得到这个错误:

System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at http://localhost:8080/oms/FileService.svc that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. ---> System.Net.WebException: The remote server returned an error: (404) Not Found.

(我确实记得更新客户端代理)

所以，这就是它对我的意义....的帮助!

protected override System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
{
    ServiceHost host = new ServiceHost(serviceType, baseAddresses);
    ContractDescription contract = ContractDescription.GetContract(serviceType);
    BasicHttpBinding binding = new BasicHttpBinding();
    binding.OpenTimeout = TimeSpan.FromMinutes(1);
    binding.ReceiveTimeout = TimeSpan.FromMinutes(1);
    binding.SendTimeout = TimeSpan.FromHours(1);
    binding.TransferMode = TransferMode.StreamedResponse;
    binding.MessageEncoding = WSMessageEncoding.Mtom;
    ServiceEndpoint streaming = new ServiceEndpoint(contract, binding, new EndpointAddress(baseAddresses[0] + "/STREAMING"));
    host.AddServiceEndpoint(streaming);
    return host;
}

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single, AddressFilterMode = AddressFilterMode.Any)]
public class FileStreamingService : IFileStreamingV1
{
    Stream IFileStreamingV1.GetFileStream(string downloadFileLocation)
    {
        if (!File.Exists(downloadFileLocation))
        {
            throw new FaultException("The file could not be found");
        }
        FileStream stream = File.OpenRead(downloadFileLocation);
        return stream;
    }
}