在WinForm中通過HTTP協議向伺服器端上傳檔案
相信用ASP.NET寫一個上傳檔案的網頁，大家都會寫，但是有沒有人想過通過在WinForm中通過HTTP協議上傳檔案呢？
有些人說要向伺服器端上傳檔案，用FTP協議不是很簡單嗎？效率又高，為什麼還要使用HTTP協議那麼麻煩呢？這裡面有幾個原因：
（1）FTP伺服器的部署相對麻煩，還要設定許可權，許可權設定不對，還會惹來一系列的安全問題。
（2）如果雙方都還有防火牆，又不想開發FTP相關的一些埠時，HTTP就會大派用場，就像WEB Services能穿透防火牆一樣。
（3）其他的...，還在想呢...
但是使用HTTP也有他的一些問題，例如不能斷點續傳，大檔案上傳很難，速度很慢，所以HTTP協議上傳的檔案大小不應該太大。
說了這麼多，原歸正傳，一般來說，在Winform裡通過HTTP上傳檔案有幾種可選的方法：
（1）前面提到的Web Services，就是一種很好的方法，通過編寫一個WebMethod，包含有 byte[] 型別的引數，然後呼叫Web Services的方法，檔案內容就會以Base64編碼傳到伺服器上，然後重新儲存即可。
[WebMethod]
public void UploadFile(byte[] content,string filename){
Stream sw = new StreamWriter(...);
sw.Close();
}
當然，這種通過Base64編碼的方法效率比較低，那麼可以採用WSE，支援附件，並以2進位制形式傳送，效率會更高。
（2）除了通過WebService，另外一種更簡單的方法就是通過WebClient或者HttpWebRequest來模擬HTTP的POST動作來實現。這時候首先需要編寫一個asp.net web form來響應上傳，程式碼如下：
<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="UploadFileWeb.WebForm1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<html>
<head>
<title>WebForm1</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="
</head>
<body>
<form id="Form1" method="post" runat="server">
</form>
</body>
</html>
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace UploadFileWeb
{
/// <summary>
/// WebForm1 的摘要說明。
/// </summary>
public class WebForm1 : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
// 在此處放置使用者程式碼以初始化頁面
foreach( string f in Request.Files.AllKeys)
{
HttpPostedFile file = Request.Files[f];
file.SaveAs(@"D:/Temp/" + file.FileName);
}
if( Request.Params["testKey"] != null )
{
Response.Write(Request.Params["testKey"]);
}
}
#region Web 窗體設計器生成的程式碼
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 該呼叫是 ASP.NET Web 窗體設計器所必需的。
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// 設計器支援所需的方法 - 不要使用程式碼編輯器修改
/// 此方法的內容。
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
}
}
其實這個頁面跟我們平常寫的asp.net上傳檔案程式碼是一樣的，在Web 頁的Request物件中包含有Files這個物件，裡面就包含了通過POST方式上傳的所有檔案的資訊，這時所需要做的就是呼叫 Request.Files[i].SaveAs方法。
但是怎麼讓才能在WinForm裡面模擬想Web Form POST 資料呢？System.Net名稱空間裡面提供了兩個非常有用的類，一個是WebClient，另外一個是HttpWebRequest類。如果我們不需要通過代理伺服器來上傳檔案，那麼非常簡單，只需要簡單的呼叫WebClient.UploadFile方法就能實現上傳檔案：
private void button1_Click(object sender, System.EventArgs e)
{
WebClient myWebClient = new WebClient();
myWebClient.UploadFile("http://localhost/UploadFileWeb/WebForm1.aspx","POST",@"D:/Temp/Java/JavaStart/JavaStart2.exe");
}
是不是覺得很簡單呢？確實就這麼簡單。
但是如果要通過代理伺服器上傳又怎麼辦呢？那就需要使用到HttpWebRequest，但是該類沒有Upload方法，但是幸運的是我們通過Reflector反編譯了WebClient.UploadFile方法後，我們發現其內部也是通過WebRequest來實現的，程式碼如下：
public byte[] UploadFile(string address, string method, string fileName)
{
string text1;
string text2;
WebRequest request1;
string text3;
byte[] buffer1;
byte[] buffer2;
long num1;
byte[] buffer3;
int num2;
WebResponse response1;
byte[] buffer4;
DateTime time1;
long num3;
string[] textArray1;
FileStream stream1 = null;
try
{
fileName = Path.GetFullPath(fileName);
time1 = DateTime.Now;
num3 = time1.Ticks;
text1 = "---------------------" + num3.ToString("x");
if (this.m_headers == null)
{
this.m_headers = new WebHeaderCollection();
}
text2 = this.m_headers["Content-Type"];
if (text2 != null)
{
if (text2.ToLower(CultureInfo.InvariantCulture).StartsWith("multipart/"))
{
throw new WebException(SR.GetString("net_webclient_Multipart"));
}
}
else
{
text2 = "application/octet-stream";
}
this.m_headers["Content-Type"] = "multipart/form-data; boundary=" + text1;
this.m_responseHeaders = null;
stream1 = new FileStream(fileName, FileMode.Open, FileAccess.Read);
request1 = WebRequest.Create(this.GetUri(address));
request1.Credentials = this.Credentials;
this.CopyHeadersTo(request1);
request1.Method = method;
textArray1 = new string[7];
textArray1[0] = "--";
textArray1[1] = text1;
textArray1[2] = "/r/nContent-Disposition: form-data; name=/"file/"; filename=/"";
textArray1[3] = Path.GetFileName(fileName);
textArray1[4] = "/"/r/nContent-Type: ";
textArray1[5] = text2;
textArray1[6] = "/r/n/r/n";
text3 = string.Concat(textArray1);
buffer1 = Encoding.UTF8.GetBytes(text3);
buffer2 = Encoding.ASCII.GetBytes("/r/n--" + text1 + "/r/n");
num1 = 9223372036854775807;
try
{
num1 = stream1.Length;
request1.ContentLength = ((num1 + ((long) buffer1.Length)) + ((long) buffer2.Length));
}
catch
{
}
buffer3 = new byte[Math.Min(((int) 8192), ((int) num1))];
using (Stream stream2 = request1.GetRequestStream())
{
stream2.Write(buffer1, 0, buffer1.Length);
do
{
num2 = stream1.Read(buffer3, 0, buffer3.Length);
if (num2 != 0)
{
stream2.Write(buffer3, 0, num2);
}
}
while ((num2 != 0));
stream2.Write(buffer2, 0, buffer2.Length);
}
stream1.Close();
stream1 = null;
response1 = request1.GetResponse();
this.m_responseHeaders = response1.Headers;
return this.ResponseAsBytes(response1);
}
catch (Exception exception1)
{
if (stream1 != null)
{
stream1.Close();
stream1 = null;
}
if ((exception1 is WebException) || (exception1 is SecurityException))
{
throw;
}
throw new WebException(SR.GetString("net_webclient"), exception1);
}
return buffer4;
}
在這段程式碼裡面其實最關鍵的就是如何模擬POST請求，通過分析程式碼和監視HTTP，我們可以發現模擬的POST格式如下：
-----------------------8c64f47716481f0 //時間戳
Content-Disposition: form-data; name="file"; filename="a.txt" //檔名
Content-Type: application/octet-stream
//檔案的內容
-----------------------8c64f47716481f0
這時候，我們只需自己編碼來模擬這麼一組資料就行（我們還可以好好借鑑MS的程式碼呢），以下就是程式碼（宣告一下，我是借用了別人的程式碼）
public class wwHttp
{
/// <summary>
/// Fires progress events when using GetUrlEvents() to retrieve a URL.
/// </summary>
public event OnReceiveDataHandler OnReceiveData;
/// <summary>
/// Determines how data is POSTed when cPostBuffer is set.
/// 1 - UrlEncoded
/// 2 - Multi-Part form vars
/// 4 - XML (raw buffer content type: text/xml)
/// </summary>
public int PostMode
{
get { return this.nPostMode; }
set { this.nPostMode = value; }
}
/// <summary>
/// User name used for Authentication.
/// To use the currently logged in user when accessing an NTLM resource you can use "AUTOLOGIN".
/// </summary>
public string Username
{
get { return this.cUsername; }
set { cUsername = value; }
}
/// <summary>
/// Password for Authentication.
/// </summary>
public string Password
{
get {return this.cPassword;}
set {this.cPassword = value;}
}
/// <summary>
/// Address of the Proxy Server to be used.
/// Use optional DEFAULTPROXY value to specify that you want to IE's Proxy Settings
/// </summary>
public string ProxyAddress
{
get {return this.cProxyAddress;}
set {this.cProxyAddress = value;}
}
/// <summary>
/// Semicolon separated Address list of the servers the proxy is not used for.
/// </summary>
public string ProxyBypass
{
get {return this.cProxyBypass;}
set {this.cProxyBypass = value;}
}
/// <summary>
/// Username for a password validating Proxy. Only used if the proxy info is set.
/// </summary>
public string ProxyUsername
{
get {return this.cProxyUsername;}
set {this.cProxyUsername = value;}
}
/// <summary>
/// Password for a password validating Proxy. Only used if the proxy info is set.
/// </summary>
public string ProxyPassword
{
get {return this.cProxyPassword;}
set {this.cProxyPassword = value;}
}
/// <summary>
/// Timeout for the Web request in seconds. Times out on connection, read and send operations.
/// Default is 30 seconds.
/// </summary>
public int Timeout
{
get {return this.nConnectTimeout; }
set {this.nConnectTimeout = value; }
}
/// <summary>
/// Error Message if the Error Flag is set or an error value is returned from a method.
/// </summary>
public string ErrorMsg
{
get { return this.cErrorMsg; }
set { this.cErrorMsg = value; }
}
/// <summary>
/// Error flag if an error occurred.
/// </summary>
public bool Error
{
get { return this.bError; }
set { this.bError = value; }
}
/// <summary>
/// Determines whether errors cause exceptions to be thrown. By default errors
/// are handled in the class and the Error property is set for error conditions.
/// (not implemented at this time).
/// </summary>
public bool ThrowExceptions
{
get { return bThrowExceptions; }
set { this.bThrowExceptions = value;}
}
/// <summary>
/// If set to a non-zero value will automatically track cookies. The number assigned is the cookie count.
/// </summary>
public bool HandleCookies
{
get { return this.bHandleCookies; }
set { this.bHandleCookies = value; }
}
public CookieCollection Cookies {
get { return this.oCookies; }
set { this.Cookies = value; }
}
public HttpWebResponse WebResponse {
get { return this.oWebResponse;}
set { this.oWebResponse = value; }
}
public HttpWebRequest WebRequest {
get { return this.oWebRequest; }
set { this.oWebRequest = value; }
}
// *** member properties
//string cPostBuffer = "";
MemoryStream oPostStream;
BinaryWriter oPostData;
int nPostMode = 1;
int nConnectTimeout = 30;
string cUserAgent = "West Wind HTTP .NET";
string cUsername = "";
string cPassword = "";
string cProxyAddress = "";
string cProxyBypass = "";
string cProxyUsername = "";
string cProxyPassword = "";
bool bThrowExceptions = false;
bool bHandleCookies = false;
string cErrorMsg = "";
bool bError = false;
HttpWebResponse oWebResponse;
HttpWebRequest oWebRequest;
CookieCollection oCookies;
string cMultiPartBoundary = "-----------------------------7cf2a327f01ae";
public void wwHTTP()
{
//
// TODO: Add constructor logic here
//
}
/// <summary>
/// Adds POST form variables to the request buffer.
/// HttpPostMode determines how parms are handled.
/// 1 - UrlEncoded Form Variables. Uses key and value pairs (ie. "Name","Rick") to create URLEncoded content
/// 2 - Multi-Part Forms - not supported
/// 4 - XML block - Post a single XML block. Pass in as Key (1st Parm)
/// other - raw content buffer. Just assign to Key.
/// </summary>
/// <param name="Key">Key value or raw buffer depending on post type</param>
/// <param name="Value">Value to store. Used only in key/value pair modes</param>
public void AddPostKey(string Key, byte[] Value)
{
if (this.oPostData == null)
{
this.oPostStream = new MemoryStream();
this.oPostData = new BinaryWriter(this.oPostStream);
}
if (Key == "RESET")
{
this.oPostStream = new MemoryStream();
this.oPostData = new BinaryWriter(this.oPostStream);
}
switch(this.nPostMode)
{
case 1:
this.oPostData.Write(Encoding.GetEncoding(1252).GetBytes(
Key + "=" + System.Web.HttpUtility.UrlEncode(Value) + "&"));
break;
case 2:
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(
"--" + this.cMultiPartBoundary + "/r/n" +
"Content-Disposition: form-data; name=/"" +Key+"/"/r/n/r/n") );
this.oPostData.Write( Value );
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes("/r/n") );
break;
default:
this.oPostData.Write( Value );
break;
}
}
public void AddPostKey(string Key, string Value)
{
this.AddPostKey(Key,Encoding.GetEncoding(1252).GetBytes(Value));
}
/// <summary>
/// Adds a fully self contained POST buffer to the request.
/// Works for XML or previously encoded content.
/// </summary>
/// <param name="PostBuffer"></param>
public void AddPostKey(string FullPostBuffer)
{
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(FullPostBuffer) );
}
public bool AddPostFile(string Key,string FileName)
{
byte[] lcFile;
if (this.nPostMode != 2) {
this.cErrorMsg = "File upload allowed only with Multi-part forms";
this.bError = true;
return false;
}
try
{
FileStream loFile = new FileStream(FileName,System.IO.FileMode.Open,System.IO.FileAccess.Read);
lcFile = new byte[loFile.Length];
loFile.Read(lcFile,0,(int) loFile.Length);
loFile.Close();
}
catch(Exception e)
{
this.cErrorMsg = e.Message;
this.bError = true;
return false;
}
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(
"--" + this.cMultiPartBoundary + "/r/n" +
"Content-Disposition: form-data; name=/"" + Key + "/" filename=/"" +
new FileInfo(FileName).Name + "/"/r/n/r/n") );
this.oPostData.Write( lcFile );
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes("/r/n")) ;
return true;
}
/// <summary>
/// Return a the result from an HTTP Url into a StreamReader.
/// Client code should call Close() on the returned object when done reading.
/// </summary>
/// <param name="Url">Url to retrieve.</param>
/// <param name="WebRequest">An HttpWebRequest object that can be passed in with properties preset.</param>
/// <returns></returns>
protected StreamReader GetUrlStream(string Url,HttpWebRequest Request)
{
try
{
this.bError = false;
this.cErrorMsg = "";
if (Request == null)
{
Request = (HttpWebRequest) System.Net.WebRequest.Create(Url);
}
Request.UserAgent = this.cUserAgent;
Request.Timeout = this.nConnectTimeout * 1000;
// *** Save for external access
this.oWebRequest = Request;
// *** Handle Security for the request
if (this.cUsername.Length > 0)
{
if (this.cUsername=="AUTOLOGIN")
Request.Credentials = CredentialCache.DefaultCredentials;
else
Request.Credentials = new NetworkCredential(this.cUsername,this.cPassword);
}
// *** Handle Proxy Server configuration
if (this.cProxyAddress.Length > 0)
{
if (this.cProxyAddress == "DEFAULTPROXY")
{
Request.Proxy = new WebProxy();
Request.Proxy = WebProxy.GetDefaultProxy();
}
else
{
WebProxy loProxy = new WebProxy(this.cProxyAddress,true);
if (this.cProxyBypass.Length > 0)
{
loProxy.BypassList = this.cProxyBypass.Split(';');
}
if (this.cProxyUsername.Length > 0)
loProxy.Credentials = new NetworkCredential(this.cProxyUsername,this.cProxyPassword);
Request.Proxy = loProxy;
}
}
// *** Handle cookies - automatically re-assign
if (this.bHandleCookies)
{
Request.CookieContainer = new CookieContainer();
if (this.oCookies != null && this.oCookies.Count > 0)
{
Request.CookieContainer.Add(this.oCookies);
}
}
// *** Deal with the POST buffer if any
if (this.oPostData != null)
{
Request.Method = "POST";
switch (this.nPostMode)
{
case 1:
Request.ContentType = "application/x-www-form-urlencoded";
// strip off any trailing & which can cause problems with some
// http servers
// if (this.cPostBuffer.EndsWith("&"))
// this.cPostBuffer = this.cPostBuffer.Substring(0,this.cPostBuffer.Length-1);
break;
case 2:
Request.ContentType = "multipart/form-data; boundary=" + this.cMultiPartBoundary;
this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes( "--" + this.cMultiPartBoundary + "/r/n" ) );
break;
case 4:
Request.ContentType = "text/xml";
break;
default:
goto case 1;
}
Stream loPostData = Request.GetRequestStream();
//loPostData.Write(lcPostData,0,lcPostData.Length);
this.oPostStream.WriteTo(loPostData);
byte[] buffer = new byte[this.oPostStream.Length];
buffer = this.oPostStream.ToArray();
Console.Write(Encoding.GetEncoding(1252).GetString(buffer,0,buffer.Length));
//*** Close the memory stream
this.oPostStream.Close();
this.oPostStream = null;
//*** Close the Binary Writer
this.oPostData.Close();
this.oPostData = null;
//*** Close Request Stream
loPostData.Close();
// *** clear the POST buffer
//this.cPostBuffer = "";
}
// *** Retrieve the response headers
HttpWebResponse Response = (HttpWebResponse) Request.GetResponse();
// ** Save cookies the server sends
if (this.bHandleCookies)
{
if (Response.Cookies.Count > 0)
{
if (this.oCookies == null)
{
this.oCookies = Response.Cookies;
}
else
{
// ** If we already have cookies update the list
foreach (Cookie oRespCookie in Response.Cookies)
{
bool bMatch = false;
foreach(Cookie oReqCookie in this.oCookies)
{
if (oReqCookie.Name == oRespCookie.Name)
{
oReqCookie.Value = oRespCookie.Name;
bMatch = true;
break; //
}
} // for each ReqCookies
if (!bMatch)
this.oCookies.Add(oRespCookie);
} // for each Response.Cookies
} // this.Cookies == null
} // if Response.Cookie.Count > 0
} // if this.bHandleCookies = 0
// *** Save the response object for external access
this.oWebResponse = Response;
Encoding enc;
try
{
if (Response.ContentEncoding.Length > 0)
enc = Encoding.GetEncoding(Response.ContentEncoding);
else
enc = Encoding.GetEncoding(1252);
}
catch
{
// *** Invalid encoding passed
enc = Encoding.GetEncoding(1252);
}
// *** drag to a stream
StreamReader strResponse =
new StreamReader(Response.GetResponseStream(),enc);
return strResponse;
}
catch(Exception e)
{
if (this.bThrowExceptions)
throw e;
this.cErrorMsg = e.Message;
this.bError = true;
return null;
}
}
/// <summary>
/// Return a the result from an HTTP Url into a StreamReader.
/// Client code should call Close() on the returned object when done reading.
/// </summary>
/// <param name="Url">Url to retrieve.</param>
/// <returns></returns>
public StreamReader GetUrlStream(string Url)
{
HttpWebRequest oHttpWebRequest = null;
return this.GetUrlStream(Url,oHttpWebRequest);
}
/// <summary>
/// Return a the result from an HTTP Url into a StreamReader.
/// Client code should call Close() on the returned object when done reading.
/// </summary>
/// <param name="Request">A Request object</param>
/// <returns></returns>
public StreamReader GetUrlStream(HttpWebRequest Request)
{
return this.GetUrlStream(Request.RequestUri.AbsoluteUri,Request);
}
/// <summary>
/// Return a the result from an HTTP Url into a string.
/// </summary>
/// <param name="Url">Url to retrieve.</param>
/// <returns></returns>
public string GetUrl(string Url)
{
StreamReader oHttpResponse = this.GetUrlStream(Url);
if (oHttpResponse == null)
return "";
string lcResult = oHttpResponse.ReadToEnd();
oHttpResponse.Close();
return lcResult;
}
/// <summary>
/// Return a the result from an HTTP Url into a string.
/// </summary>
/// <param name="Url">Url to retrieve.</param>
/// <returns></returns>
public byte[] GetUrlBytes(string Url)
{
StreamReader oHttpResponse = this.GetUrlStream(Url);
if (oHttpResponse == null)
{
return null;
}
string lcResult = oHttpResponse.ReadToEnd();
oHttpResponse.Close();
return null;
}
/// <summary>
/// Retrieves URL with events in the OnReceiveData event.
/// </summary>
/// <param name="Url"></param>
/// <param name="BufferSize"></param>
/// <returns></returns>
public string GetUrlEvents(string Url,long BufferSize)
{
StreamReader oHttpResponse = this.GetUrlStream(Url);
if (oHttpResponse == null)
return "";
long lnSize = BufferSize;
if (this.oWebResponse.ContentLength > 0)
lnSize = this.oWebResponse.ContentLength;
else
lnSize = 0;
Encoding enc = Encoding.GetEncoding(1252);
StringBuilder loWriter = new StringBuilder((int) lnSize);
char[] lcTemp = new char[BufferSize];
OnReceiveDataEventArgs oArgs = new OnReceiveDataEventArgs();
oArgs.TotalBytes = lnSize;
lnSize = 1;
int lnCount = 0;
long lnTotalBytes = 0;
while (lnSize > 0)
{
lnSize = oHttpResponse.Read(lcTemp,0,(int) BufferSize);
if (lnSize > 0)
{
loWriter.Append( lcTemp,0,(int) lnSize );
lnCount++;
lnTotalBytes += lnSize;
// *** Raise an event if hooked up
if (this.OnReceiveData != null)
{
/// *** Update the event handler
oArgs.CurrentByteCount = lnTotalBytes;
oArgs.NumberOfReads = lnCount;
oArgs.CurrentChunk = lcTemp;
this.OnReceiveData(this,oArgs);
// *** Check for cancelled flag
if (oArgs.Cancel)
goto CloseDown;
}
}
} // while
CloseDown:
oHttpResponse.Close();
// *** Send Done notification
if (this.OnReceiveData != null && !oArgs.Cancel)
{
// *** Update the event handler
oArgs.Done = true;
this.OnReceiveData(this,oArgs);
}
// return lcHtml;
return loWriter.ToString();
}
public delegate void OnReceiveDataHandler(object sender, OnReceiveDataEventArgs e);
public class OnReceiveDataEventArgs
{
public long CurrentByteCount=0;
public long TotalBytes = 0;
public int NumberOfReads = 0;
public char[] CurrentChunk;
public bool Done = false;
public bool Cancel = false;
}
}
在wwHttp這個類裡面，不僅僅可以傳送檔案AddPostFile方法，還可以傳送變數AddPostKey方法。
這樣，如果我們要通過代理伺服器傳送檔案，就可以編寫如下的程式碼了：
wwHttp ww = new wwHttp();
ww.ProxyAddress = "202.132.156.124";
ww.PostMode = 2;
ww.AddPostKey("testKey","test");
ww.AddPostFile("myfile",@"D:/Temp/Java/JavaStart/JavaStart2.jar");
string shtml = ww.GetUrlEvents("http://localhost/UploadFileWeb/WebForm1.aspx",409600);
Console.Write(shtml);
小結：
（1）通過Web Services傳檔案。
（2）如果不需要使用代理，使用WebClient類
（3）如果需要使用代理，使用擴充套件得到的類wwHttp