在WCF没出现之前,我一直使用用WebService来上传文件,我不知道别人为什么要这么做,因为我们的文件服务器和网站后台和网站前台都不在同一个机器,操作人员觉得用FTP传文件太麻烦,我就做一个专门用来上传文件的WebService,把这个WebService部署在文件服务器上,然后在网站后台调用这个WebService,把网站后台页面上传上来的文件转化为字节流传给WebService,然后WebService把这个字节流保存文件到一个只允许静态页面的网站(静态网站可以防止一些脚本木马)。 WebService来上传文件存在的问题是效率不高,而且不能传输大数据量的文件,当然你可以用Wse中的MTOM来传输大文件,有了WCF就好多了,通过使用WCF传递Stream对象来传递大数据文件,但有一些限制:
1、只有 BasicHttpBinding、NetTcpBinding 和 NetNamedPipeBinding 支持传送流数据。
2、 流数据类型必须是可序列化的 Stream 或 MemoryStream。
3、 传递时消息体(Message Body)中不能包含其他数据。
4、TransferMode的限制和MaxReceivedMessageSize的限制等。
下面具体实现:新建一个WCFService,接口文件的代码如下:
{
[OperationContract(Action = "UploadFile", IsOneWay = true)]
void UploadFile(FileUploadMessage request);
}
[MessageContract]
public class FileUploadMessage
{
[MessageHeader(MustUnderstand = true)]
public string SavePath;
[MessageHeader(MustUnderstand = true)]
public string FileName;
[MessageBodyMember(Order = 1)]
public Stream FileData;
}{
[OperationContract(Action = "UploadFile", IsOneWay = true)]
void UploadFile(FileUploadMessage request);
}
[ServiceContract] public interface IUpLoadService { [OperationContract(Action = "UploadFile", IsOneWay = true)] void UploadFile(FileUploadMessage request); }
[MessageContract] public class FileUploadMessage { [MessageHeader(MustUnderstand = true)] public string SavePath;
[MessageHeader(MustUnderstand = true)] public string FileName;
[MessageBodyMember(Order = 1)] public Stream FileData;
}
定义FileUploadMessage类的目的是因为第三个限制,要不然文件名和存放路径就没办法传递给WCF了,根据第二个限制,文件数据是用System.IO.Stream来传递的
接口方法只有一个,就是上传文件,注意方法参数是FileUploadMessage
接口实现类文件的代码如下:
public class UpLoadService : IUpLoadService { public void UploadFile(FileUploadMessage request) { string uploadFolder = @"C:\kkk\"; string savaPath = request.SavePath; string dateString = DateTime.Now.ToShortDateString() + @"\"; string fileName = request.FileName; Stream sourceStream = request.FileData; FileStream targetStream = null; if (!sourceStream.CanRead) { throw new Exception("数据流不可读!"); } if (savaPath == null) savaPath = @"Photo\"; if (!savaPath.EndsWith("\\")) savaPath += "\\";
uploadFolder = uploadFolder + savaPath + dateString; if (!Directory.Exists(uploadFolder)) { Directory.CreateDirectory(uploadFolder); }
string filePath = Path.Combine(uploadFolder, fileName); using (targetStream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None)) { //read from the input stream in 4K chunks //and save to output stream const int bufferLen = 4096; byte[] buffer = new byte[bufferLen]; int count = 0; while ((count = sourceStream.Read(buffer, 0, bufferLen)) > 0) { targetStream.Write(buffer, 0, count); } targetStream.Close(); sourceStream.Close(); } }
}
实现的功能是到指定目录下按照日期进行目录划分,然后以传过来的文件名保存文件。
这篇文章最主要的地方就是下面的Web.Config配置:
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding name="FileTransferServicesBinding" maxReceivedMessageSize="9223372036854775807"
messageEncoding="Mtom" transferMode="Streamed" sendTimeout="00:10:00" />
</basicHttpBinding>
</bindings>
<services>
<service behaviorConfiguration="UploadWcfService.UpLoadServiceBehavior"
name="UploadWcfService.UpLoadService">
<endpoint address="" binding="basicHttpBinding" bindingConfiguration="FileTransferServicesBinding" contract="UploadWcfService.IUpLoadService">
</endpoint>
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="UploadWcfService.UpLoadServiceBehavior">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="false" />
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
配置要遵循上面的第一条和第四条限制,因为默认.net只能传4M的文件,所以要在 <System.Web>配置节下面加上<httpRuntimemaxRequestLength="2097151" />
这样WCFService就完成了,新建一个Console项目或者Web项目测试一下。要注意的 是Client端的配置必须要和服务端一样,实例程序在这里下载。