在前面几篇文章中，分别就WCF如何与Ajax交互，如何返回json数据给Ajax，如何为ExtJs控件提供数据，如何用Http的访问方式异步调用Restful的WCF服务，本文着重讲述如何用Restful方式调用WCFl进行文件的上传和下载。在前面的文章中，曾经写过Restful的WCF支持两种格式的请求和响应的数据格式：1）XML 2) JSON。事实上WCF不光支持上述两种格式，它还支持原生数据(Raw,来源于Carlos' blog)。这样一来，WCF的Restful方式实际上支持任意一种格式的，因为原生的即表明可以是任意一种格式，WCF从客户端到服务端，从服务端到客户端都会保持这种数据的原来的数据格式。通过查阅MSDN中WebMessageEncodingBindingElement 类的说明：也能找到上述的论证
首先总结一下如何在Restful的WCF的服务端和客户端传递原生的数据(Raw),在WCF中，返回值或者参数为System.IO.Stream或者System.IO.Stream的派生类型的时候，加配上HTTP请求和Restful服务操作响应消息中的ContentType，便能实现原生数据的传输。
下面通过一个上传和下载图片文件的项目示例来演示如上的结论。
第一步：在VS2008中，创建一个解决方案：WcfBinaryRestful，包括四个项目：如下图所示：
其中各个项目的说明如下表所述：
|
项目名称
|
说明
|
|
WcfBinaryRestful.Contracts
|
WCF服务的契约部分
|
|
WcfBinaryRestful.Service
|
WCF服务具体实现部分
|
|
WcfBinaryRestful.Host
|
WCF服务的Console程序的承载程序
|
|
WcfBinaryRestful.Client
|
客户端
|
第二步：在WcfBinaryRestful.Contracts中创建并设计服务契约IService.cs,代码如下：
IService.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
namespace WcfBinaryRestful.Contracts
{
[ServiceContract]
public interface IService
{
[OperationContract]
System.IO.Stream ReadImg();
[OperationContract]
void ReceiveImg(System.IO.Stream stream);
}
}
其中ReadImg方法用于提供jpg图片文件，供客户端下载，而ReceiveImg用于接收客户端上传的jpg图片
第三步：在WcfBinaryRestful.Service项目中创建并设计服务具体实现类:Service.cs
Service.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel.Web;
using System.Drawing;
using System.Diagnostics;
namespace WcfBinaryRestful.Service
{
public class Service : Contracts.IService
{
[WebInvoke(Method = "*", UriTemplate = "ReadImg")]
public System.IO.Stream ReadImg()
{
string runDir = System.Environment.CurrentDirectory;
string imgFilePath = System.IO.Path.Combine(runDir, "jillzhanglogo.jpg");
System.IO.FileStream fs = new System.IO.FileStream(imgFilePath, System.IO.FileMode.Open);
System.Threading.Thread.Sleep(2000);
WebOperationContext.Current.OutgoingResponse.ContentType = "image/jpeg";
return fs;
}
[WebInvoke(Method = "*", UriTemplate = "ReceiveImg")]
public void ReceiveImg(System.IO.Stream stream)
{
Debug.WriteLine(WebOperationContext.Current.IncomingRequest.ContentType);
System.Threading.Thread.Sleep(3000);
string runDir = System.Environment.CurrentDirectory;
string imgFilePath = System.IO.Path.Combine(runDir, "ReceiveImg.jpg");
Image bmp = Bitmap.FromStream(stream);
bmp.Save(imgFilePath);
}
}
}
第四步：用配置的方式，创建服务承载项目：WcfBinaryRestful.Host。并使得服务可以用Restful方式访问。
Host.cs
Host.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
namespace WcfBinaryRestful.Host
{
public class Host
{
static void Main()
{
using (ServiceHost host = new ServiceHost(typeof(Service.Service)))
{
host.Open();
Console.WriteLine("服务已经启动！");
Console.Read();
}
}
}
}
App.config
App.config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.serviceModel>
<services>
<service name="WcfBinaryRestful.Service.Service">
<host>
<baseAddresses>
<add baseAddress="http://127.0.0.1:9874/"/>
</baseAddresses>
</host>
<endpoint address="" binding="webHttpBinding" contract="WcfBinaryRestful.Contracts.IService" behaviorConfiguration="WcfBinaryRestfulBehavior"></endpoint>
</service>
</services>
<behaviors>
<endpointBehaviors>
<behavior name="WcfBinaryRestfulBehavior">
<webHttp/>
</behavior>
</endpointBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
第五步：实现客户端程序
Form1.cs
Form1.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WcfBinaryRestful.Client
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
System.Net.WebClient wc;
private void button1_Click(object sender, EventArgs e)
{
wc = new System.Net.WebClient();
SaveFileDialog op = new SaveFileDialog();
if (op.ShowDialog() == DialogResult.OK)
{
wc.DownloadFileAsync(new Uri("http://127.0.0.1:9874/ReadImg"), op.FileName);
wc.DownloadFileCompleted += new AsyncCompletedEventHandler(wc_DownloadFileCompleted);
button2.Enabled = true;
button1.Enabled = false;
}
}
void wc_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
if (e.Cancelled)
{
button2.Enabled = false;
button1.Enabled = true;
MessageBox.Show("用户已经取消下载！");
return;
}
using (System.Net.WebClient wc = e.UserState as System.Net.WebClient)
{
button2.Enabled = false;
button1.Enabled = true;
MessageBox.Show("下载完毕!");
}
}
private void button2_Click(object sender, EventArgs e)
{
if (wc != null)
{
wc.CancelAsync();
}
}
System.Net.WebClient uploadWc = new System.Net.WebClient();
private void button3_Click(object sender, EventArgs e)
{
OpenFileDialog op = new OpenFileDialog();
op.Filter = "jpg文件(*.jpg)|*.jpg";
if (op.ShowDialog() == DialogResult.OK)
{
uploadWc.Headers.Add("Content-Type", "image/jpeg");
System.IO.FileStream fs = new System.IO.FileStream(op.FileName,System.IO.FileMode.Open);
byte[] buffer = new byte[(int)fs.Length];
fs.Read(buffer, 0, (int)fs.Length);
fs.Close();
uploadWc.UploadDataCompleted += new System.Net.UploadDataCompletedEventHandler(uploadWc_UploadDataCompleted);
uploadWc.UploadDataAsync(new Uri("http://127.0.0.1:9874/ReceiveImg"), buffer);
button3.Enabled = false;
button4.Enabled = true;
}
}
void uploadWc_UploadDataCompleted(object sender, System.Net.UploadDataCompletedEventArgs e)
{
if (e.Cancelled)
{
button3.Enabled = true;
button4.Enabled = false;
MessageBox.Show("用户已经取消上传！");
return;
}
MessageBox.Show("完成上传！");
button3.Enabled = true;
button4.Enabled = false;
}
private void button4_Click(object sender, EventArgs e)
{
uploadWc.CancelAsync();
}
}
}
设置好多启动项目调试后，调试，出现如下的运行界面：
1.服务承载程序运行界面图：
2.客户端运行界面图：
点击开始下载按钮，选择一个下载文件的保存位置，等待一会后，会提示下载成功，如下图所示：
打开刚才选择下载文件的保存位置，便能发现已经成功下载了jpg的图片文件：
当然顺便还可以温习一下如何异步调用Restful的WCF服务，点击取消下载可以停止下载，不再多说
点击开始上传，选择一个要上传的jpg图片，等待几秒钟，便能收到上传成功的对话框，如下图所示：
找到服务承载程序所在目录，便能看到上传的jpg图像文件：
示例项目文件：