asp.net httprequest httpresponse

问题:有的网站的相关内容必须要在登录后才可以查看,其登录信息保存在session变量之中。这样,使用asphttp等组件就难以正确得到所要的信息。

解决:使用asp.net中的httprequest和httpresponse来实现。

要点:

1。 通过附加一个cookiecontainer到httprequest对象中,可以得到登录后返回的代表SESSION ID的COOKIE。 见Login方法

2。 将此COOKIE包含在一个cookiecontainer中并附加到另一个HTTPREQUEST请求中,则可以实现SESSION的还原。见getPage方法

源程序如下:

getHttpInfo.aspx:

<%@ Page language="c#" Codebehind="getHttpInfo.aspx.cs" AutoEventWireup="false" Inherits="PdfTest.getHttpInfo" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >

<HTML>

<HEAD>

<title>WebForm1</title>

<meta content="Microsoft Visual Studio 7.0" name="GENERATOR">

<meta content="C#" name="CODE_LANGUAGE">

<meta content="JavaScript" name="vs_defaultClientScript">

<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">

</HEAD>

<body>

<form >

</form>

</body>

</HTML>

getHttpInfo.aspx.cs:

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

//using System.Data.OleDb;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Net;

using System.IO;

using System.Text;

using System.Text.RegularExpressions;

using Microsoft.Data.Odbc;

namespace PdfTest

{

/// <summary>

/// Summary description for WebForm1.

/// </summary>

public class getHttpInfo : System.Web.UI.Page

{

protected static string cookieheader;

private void Page_Load(object sender, System.EventArgs e)

{

// Put user code to initialize the page here

string strResult;

if (HttpContext.Current.Application["cookieheader"] != null)

{

cookieheader = (string)HttpContext.Current.Application["cookieheader"];

}

else

{

//Login into the website and keep the cookie for the session in the application variable

string strLogin = Login("http://www.thesiteyouwanttovisit/theloginpage.asp", "Action=&USER) ;

}

strResult = getPage("http://www.thesiteyouwanttovisit/theloginpage.asp", "Action=&data=") ;

//Write the result to htm file

FileStream htmFile = new FileStream("c:\save.htm", FileMode.OpenOrCreate);

StreamWriter sw = new StreamWriter(htmFile);

sw.Write(strResult);

sw.Close();

htmFile.Close();

// output the result

Response.Write(strResult);

}

public static string Login(String url, String paramList)

{

HttpWebResponse res = null;

string strResult="";

try

{

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

req.Method = "POST";

req.ContentType = "application/x-www-form-urlencoded";

req.AllowAutoRedirect = false;

CookieContainer cookieCon = new CookieContainer();

req.CookieContainer = cookieCon;

StringBuilder UrlEncoded = new StringBuilder();

Char[] reserved = {'?', '=', '&'};

byte[] SomeBytes = null;

if (paramList != null)

{

int i=0, j;

while(i<paramList.Length)

{

j=paramList.IndexOfAny(reserved, i);

if (j==-1)

{

UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i)));

break;

}

UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i)));

UrlEncoded.Append(paramList.Substring(j,1));

i = j+1;

}

SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString());

req.ContentLength = SomeBytes.Length;

Stream newStream = req.GetRequestStream();

newStream.Write(SomeBytes, 0, SomeBytes.Length);

newStream.Close();

}

else

{

req.ContentLength = 0;

}

res = (HttpWebResponse)req.GetResponse();

cookieheader = req.CookieContainer.GetCookieHeader(new Uri(url));

HttpContext.Current.Application.Lock();

HttpContext.Current.Application["cookieheader"] = cookieheader;

HttpContext.Current.Application.UnLock();

Stream ReceiveStream = res.GetResponseStream();

Encoding encode = System.Text.Encoding.GetEncoding("utf-8");

StreamReader sr = new StreamReader( ReceiveStream, encode );

Char[] read = new Char[256];

int count = sr.Read( read, 0, 256 );

while (count > 0)

{

String str = new String(read, 0, count);

strResult += str;

count = sr.Read(read, 0, 256);

}

}

catch(Exception e)

{

strResult = e.ToString();

}

finally

{

if ( res != null )

{

res.Close();

}

}

return strResult;

}

public static string getPage(String url, String paramList)

{

HttpWebResponse res = null;

string strResult = "";

try

{

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

req.Method = "POST";

req.KeepAlive = true;

req.ContentType = "application/x-www-form-urlencoded";

CookieContainer cookieCon = new CookieContainer();

req.CookieContainer = cookieCon;

req.CookieContainer.SetCookies(new Uri(url),cookieheader);

StringBuilder UrlEncoded = new StringBuilder();

Char[] reserved = {'?', '=', '&'};

byte[] SomeBytes = null;

if (paramList != null)

{

int i=0, j;

while(i<paramList.Length)

{

j=paramList.IndexOfAny(reserved, i);

if (j==-1)

{

UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i)));

break;

}

UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i)));

UrlEncoded.Append(paramList.Substring(j,1));

i = j+1;

}

SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString());

req.ContentLength = SomeBytes.Length;

Stream newStream = req.GetRequestStream();

newStream.Write(SomeBytes, 0, SomeBytes.Length);

newStream.Close();

}

else

{

req.ContentLength = 0;

}

res = (HttpWebResponse)req.GetResponse();

Stream ReceiveStream = res.GetResponseStream();

Encoding encode = System.Text.Encoding.GetEncoding("utf-8");

StreamReader sr = new StreamReader( ReceiveStream, encode );

Char[] read = new Char[256];

int count = sr.Read( read, 0, 256 );

while (count > 0)

{

String str = new String(read, 0, count);

strResult += str;

count = sr.Read(read, 0, 256);

}

}

catch(Exception e)

{

strResult = e.ToString();

}

finally

{

if ( res != null )

{

res.Close();

}

}

return strResult;

}

#region Web Form Designer generated code

override protected void OnInit(EventArgs e)

{

//

// CODEGEN: This call is required by the ASP.NET Web Form Designer.

//

InitializeComponent();

base.OnInit(e);

}

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.Load += new System.EventHandler(this.Page_Load);

}

#endregion

}

}

//通过Post发送的数据

string payload="chkbook=book&keyword=管理";

WebRequest req = WebRequest.Create("http://localhost/pceo/Search.aspx");

req.Method = "POST";

req.ContentType = "application/x-www-form-urlencoded";

StringBuilder UrlEncoded = new StringBuilder();

Char[] reserved = {'?', '=', '&'};

byte[] SomeBytes = null;

if (payload != null)

{

int i=0, j;

while(i<payload.Length)

{

j=payload.IndexOfAny(reserved, i);

if (j==-1)

{

UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, payload.Length-i),System.Text .Encoding .GetEncoding ("gb2312")));

break;

}

UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, j-i),System.Text .Encoding .GetEncoding ("gb2312")));

UrlEncoded.Append(payload.Substring(j,1));

i = j+1;

}

SomeBytes = Encoding.Default.GetBytes(UrlEncoded.ToString());

req.ContentLength = SomeBytes.Length;

Stream newStream = req.GetRequestStream();

newStream.Write(SomeBytes, 0, SomeBytes.Length);

newStream.Close();

}

else

{

req.ContentLength = 0;

}

try

{

WebResponse result = req.GetResponse();

Stream ReceiveStream = result.GetResponseStream();

Byte[] read = new Byte[512];

int bytes = ReceiveStream.Read(read, 0, 512);

txtHTML.InnerHtml = "";

while (bytes > 0)

{

// 注意:

// 下面假定响应使用 UTF-8 作为编码方式。

// 如果内容以 ANSI 代码页形式(例如,932)发送,则使用类似下面的语句:

// Encoding encode = System.Text.Encoding.GetEncoding("shift-jis");

Encoding encode = System.Text.Encoding.GetEncoding("gb2312");

txtHTML.InnerHtml = txtHTML.InnerHtml + encode.GetString(read, 0, bytes);

bytes = ReceiveStream.Read(read, 0, 512);

}

}

catch(Exception)

{

txtHTML.InnerHtml = "检索页时出错";

}

最近有个朋友离开IT行业二年的朋友说要实现用程序向某个网站的页面上传数据,他是意思是每天有几十条数据要在网站页面上填写,很烦,最好用程序来写。网站页面是用POST传递的,同时没有验证码之类的东东,只有一点限制就是5分种内不能填写二次记录。这一切都好办。

using System.Web;

using System.Net;

using System.Text;

using System.IO;

//创建对某个网站页面的请求

HttpWebRequest myRequest = (HttpWebRequest )WebRequest.Create("http://www.knowsky.com/a.asp")

//上传的数据,”TextBox1“这些东东是网站页面里的控件ID,如果要上传多个值也是用&来分隔

string postData="TextBox1="+this.textBox1.Text+"&TextBox2="+this.textBox2.Text+"

&TextBox3="+this.textBox3.Text+"&TextBox4="+this.textBox4.Text;

ASCIIEncoding encoding=new ASCIIEncoding();

byte[] byte1=encoding.GetBytes(postData);//最终编码后要上传的数据

// Set the content type of the data being posted.

myRequest.ContentType="application/x-www-form-urlencoded";

myRequest.Method="post";//post上传方式

// Set the content length of the string being posted.

myRequest.ContentLength=postData.Length;

Stream newStream=myRequest.GetRequestStream();

newStream.Write(byte1,0,byte1.Length);

一切就OK了,如果你想上传后看到网站的内容的话,可以在程序里放一个IE控件,使用

axWebBrowser1.Navigate("http://www.knowsky.com/a.asp");

axWebBrowser1.Refresh2();