用Restful方式調用WCF進行上傳下載

用Restful方式調用WCF進行上傳下載

2008-07-16 21:36

原文： 用Restful方式調用WCF進行上傳下載

在 前面幾篇文章中，分別就WCF如何與Ajax交互，如何返回json數據給Ajax，如何爲ExtJs控件提供數據，如何用Http的訪問方式異步調用 Restful的WCF服務，本文着重講述如何用Restful方式調用WCFl進行文件的上傳和下載。在前面的文章中，曾經寫過Restful的WCF 支持兩種格式的請求和響應的數據格式：1）XML 2) JSON。事實上WCF不光支持上述兩種格式，它還支持原生數據(Raw,來源於Carlos' blog)。 這樣一來，WCF的Restful方式實際上支持任意一種格式的，因爲原生的即表明可以是任意一種格式，WCF從客戶端到服務端，從服務端到客戶端都會保 持這種數據的原來的數據格式。通過查閱MSDN中WebMessageEncodingBindingElement 類的說明：也能找到上述的論證

首 先總結一下如何在Restful的WCF的服務端和客戶端傳遞原生的數據(Raw),在WCF中，返回值或者參數爲System.IO.Stream或者 System.IO.Stream的派生類型的時候，加配上HTTP請求和Restful服務操作響應消息中的ContentType，便能實現原生數據 的傳輸。

下面通過一個上傳和下載圖片文件的項目示例來演示如上的結論。

第一步：在VS2008中，創建一個解決方案：WcfBinaryRestful，包括四個項目：如下圖所示：

其中各個項目的說明如下表所述：

項目名稱	說明
WcfBinaryRestful.Contracts	WCF服務的契約部分
WcfBinaryRestful.Service	WCF服務具體實現部分
WcfBinaryRestful.Host	WCF服務的Console程序的承載程序
WcfBinaryRestful.Client	客戶端

第二步：在WcfBinaryRestful.Contracts中創建並設計服務契約IService.cs,代碼如下：

 

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方法用於提供jpg圖片文件，供客戶端下載，而ReceiveImg用於接收客戶端上傳的jpg圖片

第三步：在WcfBinaryRestful.Service項目中創建並設計服務具體實現類: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，創建服務承載項目：WcfBinaryRestful.Host。並使得服務可以用Restful方式訪問。

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("服務已經啓動！");
                 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：實現客戶端程序

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("用戶已經取消下載！");
                return;
            }
            using (System.Net.WebClient wc = e.UserState as System.Net.WebClient)
            {
                button2.Enabled = false;
                button1.Enabled = true;
                MessageBox.Show("下載完畢!");
            }
        }

        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;
            }
        }  
}