asp.net下实现支持文件分块多点异步上传的 Web Services

时间:2021-03-17 人气:0

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本文的客户端应用程序不包括 ASP.Net Web 应用程序!

本文假设 URL: http://localhost/mywebservices/updownload.asmx

共有 4 个程序文件 (Web.Config 就不赘述了)

Server Side:

标题中所提到的 "异步" 其实在服务器端的程序并没有什么特殊的,而主要是通过客户端应用程序
异步调用相关 Web Method 实现的!

1. updownload.asmx ,位于 IIS 的某个 Web 共享目录,代码如下,只有一句话:

<%@ WebService Language="c#" Codebehind="UpDownLoad.asmx.cs" Class="Service1" %>

2. updownload.asmx.cs ,即: updownload.asmx 的 Codebehind ,位于 IIS 的某个 Web 共享目录的 bin 子目录下,代码如下:

/*

本文件位于 Web 共享目录的 bin 子目录下,通过执行如下命令行编译:
csc /t:library updownload.asmx.cs

*/
using System.Diagnostics;
using System.Web;
using System.Web.Services;
using System.IO;
using System;

public class Service1 : System.Web.Services.WebService
{
[WebMethod]
public string HelloWorld()
{
  return "Hello World";
}

//从 Web Method 本身,其实看不出 "同步" 还是 "异步"
[WebMethod(Description = "为了支持多点分块异步上传文件,此方法必须由客户端预先调用,以便在服务器端生成指定 FileName 和 Length 大小的空白文件预定空间! 建议客户端同步调用")]
public string CreateBlankFile(string FileName,int Length) //建议由客户端同步调用
{
  FileStream fs = new FileStream(Server.MapPath(".") + "\\" + FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
  fs.Write(new byte[Length], 0, Length);
  fs.Close();
  fs = null;
  return FileName + " (" + Length + ") 空白文件已经创建!";
}

[WebMethod(Description = "提供一个用于一次完整上传整个文件的方法! 建议客户端同步调用")]
public string UploadFileBytes(byte[] Bytes,string FileName)
{
  return UploadFileChunkBytes(Bytes, 0, FileName);
}

[WebMethod(Description = "提供一个用于一次只上传由 Position 位置起始的, Bytes 字节的 FileName 文件块存入服务器端相应文件的相应字节位置! 建议客户端异步调用")]
// 这里只要多提供一个 Position 参数,余下的再由客户端调用异步的该方法,就轻松达到目的了!
public string UploadFileChunkBytes(byte[] Bytes,int Position,string FileName)
{
  try
  {
   FileStream fs = new FileStream(Server.MapPath(".") + "\\" + FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
   //该 Bytes 的字节要写到服务器端相应文件的从 Position 开始的字节
   fs.Position = Position;
   fs.Write(Bytes, 0, Bytes.Length);
   fs.Close();
   fs = null;
   return FileName + " 文件块: 位置[" + Position + "," + (Position + Bytes.Length) + "] 大小(" + Bytes.Length + ") 上传成功!";
  }
  catch (Exception e)
  {
   return e.Message;
  }
}

[WebMethod]
public byte[] DownloadFileBytes(string FileName)
{
  if (File.Exists(FileName))
  {
   try
   {
    FileStream fs = File.OpenRead(FileName);
    int i = (int) fs.Length;
    byte[] ba = new byte[i];
    fs.Read(ba,0,i);
    fs.Close();
    return ba;
   }
   catch
   {
    return new byte[0];
   }
  }
  else
  {
   return new byte[0];
  }
}
}

//=======================================================================

Client Side:
3. UpDownloadProxy.cs :
本文件由如下命令生成
% Visual Studio .Net 2003 安装目录下的 %\SDK\v1.1\Bin\wsdl.exe
具体命令行如下:
wsdl.exe /l:CS /out:UpDownloadProxy.cs http://localhost/MyWebServices/updownload.asmx?wsdl
生成的本地的客户端代理类代码里已经为每个 Web Method 生成了可异步和同步执行的方法,例如:
    public string HelloWorld() {}
    public System.IAsyncResult BeginHelloWorld(...) {}
    public string EndHelloWorld(...) {}

下面是该命令行生成的完整的 UpDownloadProxy.cs 代码,就不修改了:
/*

通过执行如下命令行编译,生成 UpDownloadProxy.dll :
csc /t:library UpDownloadProxy.cs

*/

//------------------------------------------------------------------------------
// <autogenerated>
//     This code was generated by a tool.
//     Runtime Version: 1.1.4322.573
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </autogenerated>
//------------------------------------------------------------------------------

//
// 此源代码由 wsdl, Version=1.1.4322.573 自动生成。
//
using System.Diagnostics;
using System.Xml.Serialization;
using System;
using System.Web.Services.Protocols;
using System.ComponentModel;
using System.Web.Services;

/// <remarks/>
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Web.Services.WebServiceBindingAttribute(Name="Service1Soap", Namespace="http://tempuri.org/")]
public class Service1 : System.Web.Services.Protocols.SoapHttpClientProtocol {

    /// <remarks/>
    public Service1() {
        this.Url = "http://localhost/MyWebServices/updownload.asmx";
    }

    /// <remarks/>
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/HelloWorld", RequestNamespace="http://tempuri.org/", ResponseNamespace="http://tempuri.org/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
    public string HelloWorld() {
        object[] results = this.Invoke("HelloWorld", new object[0]);
        return ((string)(results[0]));
    }

    /// <remarks/>
    public System.IAsyncResult BeginHelloWorld(System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("HelloWorld", new object[0], callback, asyncState);
    }

    /// <remarks/>
    public string EndHelloWorld(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((string)(results[0]));
    }

    /// <remarks/>
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/CreateBlankFile", RequestNamespace="http://tempuri.org/", ResponseNamespace="http://tempuri.org/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
    public string CreateBlankFile(string FileName, int Length) {
        object[] results = this.Invoke("CreateBlankFile", new object[] {
                    FileName,
                    Length});
        return ((string)(results[0]));
    }

    /// <remarks/>
    public System.IAsyncResult BeginCreateBlankFile(string FileName, int Length, System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("CreateBlankFile", new object[] {
                    FileName,
                    Length}, callback, asyncState);
    }

    /// <remarks/>
    public string EndCreateBlankFile(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((string)(results[0]));
    }

    /// <remarks/>
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/UploadFileBytes", RequestNamespace="http://tempuri.org/", ResponseNamespace="http://tempuri.org/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
    public string UploadFileBytes([System.Xml.Serialization.XmlElementAttribute(DataType="base64Binary")] System.Byte[] Bytes, string FileName) {
        object[] results = this.Invoke("UploadFileBytes", new object[] {
                    Bytes,
                    FileName});
        return ((string)(results[0]));
    }

    /// <remarks/>
    public System.IAsyncResult BeginUploadFileBytes(System.Byte[] Bytes, string FileName, System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("UploadFileBytes", new object[] {
                    Bytes,
                    FileName}, callback, asyncState);
    }

    /// <remarks/>
    public string EndUploadFileBytes(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((string)(results[0]));
    }

    /// <remarks/>
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/UploadFileChunkBytes", RequestNamespace="http://tempuri.org/", ResponseNamespace="http://tempuri.org/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
    public string UploadFileChunkBytes([System.Xml.Serialization.XmlElementAttribute(DataType="base64Binary")] System.Byte[] Bytes, int Position, string FileName) {
        object[] results = this.Invoke("UploadFileChunkBytes", new object[] {
                    Bytes,
                    Position,
                    FileName});
        return ((string)(results[0]));
    }

    /// <remarks/>
    public System.IAsyncResult BeginUploadFileChunkBytes(System.Byte[] Bytes, int Position, string FileName, System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("UploadFileChunkBytes", new object[] {
                    Bytes,
                    Position,
                    FileName}, callback, asyncState);
    }

    /// <remarks/>
    public string EndUploadFileChunkBytes(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((string)(results[0]));
    }

    /// <remarks/>
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/DownloadFileBytes", RequestNamespace="http://tempuri.org/", ResponseNamespace="http://tempuri.org/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
    [return: System.Xml.Serialization.XmlElementAttribute(DataType="base64Binary")]
    public System.Byte[] DownloadFileBytes(string FileName) {
        object[] results = this.Invoke("DownloadFileBytes", new object[] {
                    FileName});
        return ((System.Byte[])(results[0]));
    }

    /// <remarks/>
    public System.IAsyncResult BeginDownloadFileBytes(string FileName, System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("DownloadFileBytes", new object[] {
                    FileName}, callback, asyncState);
    }

    /// <remarks/>
    public System.Byte[] EndDownloadFileBytes(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((System.Byte[])(results[0]));
    }
}

//=======================================================================
4. UpDownloadClient.cs :
该程序才是真正实现文件分块多点异步上传的核心代码:

/*

通过执行如下命令行编译:
csc updownloadClient.cs /r:updownloadproxy.dll

*/
using System;
using System.IO;

public class Class1
{
static void Main(string[] args)
{
  //Download(ServerSidepath, ClientSidePath)
  Download(@"e:\test.jpg", @"f:\test_local.jpg");
  System.Console.WriteLine("down End");

  System.Console.WriteLine("同步 up file exec ...");
  UploadFile(@"e:\Northwind.mdb");
  System.Console.WriteLine("同步 up file End\n");

  System.Console.WriteLine("异步 up chunks exec ...");
  UploadFileChunks(@"e:\test.rar", 64);
  System.Console.ReadLine();
}

public static void UploadFile(string LocalFileName)
{
  Service1 xx = new Service1();
  FileStream fs = new FileStream(LocalFileName, FileMode.Open); //Client Side Path
  byte[] buffer = new byte[fs.Length];
  fs.Read(buffer, 0, buffer.Length);
  //调用 "同步执行" 的本地 Web Sevices 代理类的方法,相当于同步调用了 Web Method !
  xx.UploadFileBytes(buffer, System.IO.Path.GetFileName(LocalFileName));
}

//指定要上传的本地文件的路径,及每次上传文件块的大小
public static void UploadFileChunks(string LocalFileName,int ChunkSize)
{
  Service1 xx = new Service1();
  string filename = System.IO.Path.GetFileName(LocalFileName);

  FileStream fs = new FileStream(LocalFileName, FileMode.Open); //Client Side Path
  //fs = File.OpenRead(LocalFileName);

  int r = (int) fs.Length; //用于记录剩余还未上传的字节数,初值是文件的大小

  //调用 "同步执行" 的本地 Web Sevices 代理类的方法,相当于同步调用了 Web Method !
  //预定服务器端空间
  xx.CreateBlankFile(filename,r);
  int size = ChunkSize * 1024;
  int k = 0; //用于记录已经上传的字节数
  i++; //用于记录上传的文件块数
  while (r >= size)
  {
   byte[] buffer = new byte[size];
   fs.Read(buffer,0,buffer.Length);
   //调用 "异步执行" 的本地 Web Sevices 代理类的方法,相当于异步调用了 Web Method !
   //该 buffer 的字节要写到服务器端相应文件的从 Position = k 开始的字节
   xx.BeginUploadFileChunkBytes(buffer,k,filename,new AsyncCallback(UploadFileChunkCallback),xx);
   k += size;
   r -= size;
   i++;
  }
  if (r > 0) //剩余的零头
  {
   byte[] buffer = new byte[r];
   fs.Read(buffer,0,buffer.Length);
   //调用 "异步执行" 的本地 Web Sevices 代理类的方法,相当于异步调用了 Web Method !
   //该 buffer 的字节要写到服务器端相应文件的从 Position = k 开始的字节
   xx.BeginUploadFileChunkBytes(buffer,k,filename,new AsyncCallback(UploadFileChunkCallback),xx);
   i++;
  }
  fs.Close();

}

private static int i = -1; //用于记录上传的文件块数

private static void UploadFileChunkCallback(IAsyncResult ar)
{
  Service1 x = (Service1) ar.AsyncState;
  Console.WriteLine(x.EndUploadFileChunkBytes(ar));
  if ( --i == 0)
  {
   Console.WriteLine("异步 up all chunks end");
  }
}

public static void Download(string ServerSideFileName,string LocalFileName)
{
  Service1 xx = new Service1();
  byte[] ba = xx.DownloadFileBytes(ServerSideFileName); //Server Side Path

  FileStream fs = new FileStream(LocalFileName, FileMode.Create); //Client Side Path
  fs.Write(ba,0,ba.Length);
  fs.Close();
}
}

//===========================================================================
至此我们通过纯手工的方式完成了任务,之所以不用 VS 就是为了让码子简洁明了!
Microshaoft .Night 就是这么平易近人! (PMPMP to MS)
通过 Web Sevices 上传文件非常简单,甚至比传统的 http Web 上传还简单!
同时较轻松地就实现了文件分块多点异步上传:
Server 端代码没啥特殊的!
Client 端代码稍微复杂些!

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