HttpRequest獲取網站信息的程序示例

2019-11-18 19:52:06

字體：大中小

來源：轉載

供稿：網友

問題：有的網站的相關內容必須要在登錄后才可以查看，其登錄信息保存在session變量之中。這樣，使用asphttp等組件就難以正確得到所要的信息。

解決：使用asp.net中的httPRequest和httpresponse來實現。

要點：
1。通過附加一個cookiecontainer到httprequest對象中，可以得到登錄后返回的代表SESSION ID的COOKIE。見Login方法
2。將此COOKIE包含在一個cookiecontainer中并附加到另一個HTTPREQUEST請求中，則可以實現SESSION的還原。見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="javaScr<meta content="</HEAD>
<body>
<form id="Form1" method="post" runat="server">
</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("Word=") ;
}

strResult = getPage("

//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;
}