以编程方式提交表单

Question

我正在尝试以编程方式提交特定表单，但我总是会返回初始页面。 我一定是做错了什么或在这里遗漏了什么。 我发送会话 cookie 和一些 POST 数据，如 viewState（我从初始请求中解析）和 SessionID（这是我在表单中更改的值以获取其他年份的数据）。但在第二个请求中，我总是获取 Session 899 的数据，而不是我请求的那个：875。

这里是使用的代码：，非常感谢任何帮助

retrieveEdmIndexForSession(875);

 protected string retrieveEdmIndexForSession(int sessionId) {

    CookieContainer cookies;
    HttpWebRequest oRequest;
    HttpWebResponse oResponse;
    Stream sw;
    StreamReader sr;
    string pageData;
string PathRemote = @"http://edmi.parliament.uk/EDMi/EDMList.aspx";


    /*
     * download the index page so we can get Cookies and ViewState from it.
     */
    oRequest = (HttpWebRequest)WebRequest.Create(PathRemote);
    oRequest.Method = "GET";
    oRequest.AllowAutoRedirect = true;
    oRequest.CookieContainer = new CookieContainer();
    oRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    oRequest.Referer = "http://edmi.parliament.uk/EDMi/EDMList.aspx";


    oResponse =(HttpWebResponse) oRequest.GetResponse();
    sr = new StreamReader(oResponse.GetResponseStream());

    pageData = sr.ReadToEnd();

    /*
     * extract view state from pageData.
     */
    string viewState = this.ExtractViewState(pageData);


    /*
    * lets submit the form with the parameters we want
    */
    oRequest = (HttpWebRequest)WebRequest.Create(PathRemote);
    oRequest.Method = "POST";
    oRequest.AllowAutoRedirect = true;
    oRequest.ContentType = "application/x-www-form-urlencoded";
    oRequest.CookieContainer = new CookieContainer();
    oRequest.CookieContainer.Add(oResponse.Cookies);
    oRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    oRequest.Referer = "http://edmi.parliament.uk/EDMi/EDMList.aspx";

    string postdata = "__EVENTTARGET=&__EVENTARGUMENT=&__VIEWSTATE=" + viewState + "&_MenuCtrl%3AddlSession=" + sessionId + "&_MenuCtrl%3A_GoTo.x=57&_MenuCtrl%3A_GoTo.y=14&ddlStatus=1&ddlSortedBy=1";
    byte[] buffer = Encoding.UTF8.GetBytes(postdata);
    oRequest.ContentLength = buffer.Length;

    /*
     * Send post data into request stream first
     */
    sw = oRequest.GetRequestStream();
    sw.Write(buffer, 0, buffer.Length);
    sw.Flush();
    sw.Close();

    /*
     * Connect, send and get response
     */
    oResponse = (HttpWebResponse)oRequest.GetResponse();
    sr = new StreamReader(oResponse.GetResponseStream());

    //OnLogUpdated(1, "\r\nStatus Code: " + oResponse.StatusCode);
    //OnLogUpdated(1, "\r\nServer: " + oResponse.Server);

    pageData = sr.ReadToEnd();
    string result = getSessionId(pageData);
    //OnLogUpdated(1, "\r\nRestuls: [" + result + "]");
    //OnLogUpdated(1, "\r\nPage: [" + pageData + "]");


    return pageData;


}



private string ExtractViewState(string str)
{
    string viewState = "";
    string pattern = "(?<=__VIEWSTATE\" value=\")(?<val>.*?)(?=\")";

    Match match = Regex.Match(str, pattern);

    if (match.Success)
    {
        viewState = match.Groups["val"].Value;
        viewState = HttpUtility.UrlEncodeUnicode(viewState);

    }

    return viewState;
}

protected string getSessionId(string str)
{
    string sessionId = string.Empty;

    str = str.Trim();

    string pattern = @"&SESSION=([^']+)'";

    Match match = Regex.Match(str, pattern, RegexOptions.IgnoreCase);
    if (match.Success)
    {
        sessionId = match.Groups[1].ToString(); ;

    }

    return sessionId;
}

这是 .NET 脚本发送的 RAW 请求。

POST /EDMi/EDMList.aspx HTTP/1.1 内容类型： 应用程序/x-www-form-urlencoded 接受： text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8 推荐人： http://edmi.parliament.uk/EDMi/EDMList.aspx 用户代理：.NET Framework 客户端 主持人：edmi.parliament.uk Cookie： ASP.NET_SessionId=k55fqarvx2oszp2wxhtrol45 内容长度：2431 期望： 100-继续

__ EVENTTARGET =＆__ EVENTARGUMENT =＆__ VIEWSTATE = dDwxMDgyNzIxNDQ2O3Q8O2w8aTwzPjs％2bO2w8dDw7bDxpPDE％2bO2k8Mz47aTw1PjtpPDExPjs％2bO2w8dDw7bDxpPDEzPjtpPDE3Pjs％2bO2w8dDx0PHA8cDxsPERhdGFWYWx1ZUZpZWxkO0RhdGFUZXh0RmllbGQ7PjtsPFNFU1NJT05JRDtJVEVNX1ZBTFVFOz4％2bOz47dDxpPDIwPjtAPDA4LTA5OzA3LTA4OzA2LTA3OzA1LTA2OzA0LTA1OzAzLTA0OzAyLTAzOzAxLTAyOzAwLTAxOzk5LTAwOzk4LTk5Ozk3LTk4Ozk2LTk3Ozk1LTk2Ozk0LTk1OzkzLTk0OzkyLTkzOzkxLTkyOzkwLTkxOzg5LTkwOz47QDw4OTk7ODkxOzg4NTs4NzU7ODczOzY4Mjs2ODE7NjgwOzY3OTs3MDM7NzAyOzcwMTs3MDA7Njk5OzY5ODs2OTc7Njk2OzY5NTs2OTQ7NjkzOz4％2bOz47Oz47dDxwPGw8VGV4dDs％2bO2w8TGlzdCBPZiBFYXJseSBEYXkgTW90aW9uczs％2bPjs7Pjs％2bPjt0PDtsPGk8MT47aTwzPjs％2bO2w8dDx0PDs7bDxpPDA％2bOz4％2bOzs％2bO3Q8dDw7O2w8aTwwPjs％2bPjs7Pjs％2bPjt0PDtsPGk8MT47aTwzPjs％2bO2w8dDw7bDxpPDE％2bO2k8Mz47aTw1PjtpPDc％2bOz47bDx0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztFbmFibGVkO18hU0I7PjtsPDA7UGFnZUZpcnN0RGlzYWJsZWQ7bzxmPjtpPDI％2bOz4％2bOz47Oz47dDxwPHA8bDxDb21tYW5kQXJndW1lbnQ7Q3NzQ2xhc3M7RW5hYmxlZDtfIVNCOz47bDwtMTtQYWdlUHJldkRpc2FibGVkO 288Zj47aTwyPjs％2bPjs％2bOzs％2bO3Q8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO18hU0I7PjtsPDE7UGFnZU5leHRFbmFibGVkO2k8Mj47Pj47Pjs7Pjt0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztfIVNCOz47bDw0MjtQYWdlTGFzdEVuYWJsZWQ7aTwyPjs％2bPjs％2bOzs％2bOz4％2bO3Q8O2w8aTwxPjtpPDM％2bO2k8NT47aTw3Pjs％2bO2w8dDxwPHA8bDxUZXh0Oz47bDwyMTA5Oz4％2bOz47Oz47dDxwPHA8bDxUZXh0Oz47bDxFRE1zIGFuZCBBbWVuZG1lbnRzOz4％2bOz47Oz47dDxwPHA8bDxUZXh0Oz47bDwxOz4％2bOz47Oz47dDxwPHA8bDxUZXh0Oz47bDw1MDs％2bPjs％2bOzs％2bOz4％2bOz4％2bO3Q8O2w8aTwxPjtpPDM％2bOz47bDx0PDtsPGk8MT47aTwzPjtpPDU％2bO2k8Nz47PjtsPHQ8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO0VuYWJsZWQ7XyFTQjs％2bO2w8MDtQYWdlRmlyc3REaXNhYmxlZDtvPGY％2bO2k8Mj47Pj47Pjs7Pjt0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztFbmFibGVkO18hU0I7PjtsPC0xO1BhZ2VQcmV2RGlzYWJsZWQ7bzxmPjtpPDI％2bOz4％2bOz47Oz47dDxwPHA8bDxDb21tYW5kQXJndW1lbnQ7Q3NzQ2xhc3M7XyFTQjs％2bO2w8MTtQYWdlTmV4dEVuYWJsZWQ7aTwyPjs％ 2bPjs%2bOzs%2bO3Q8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO18hU0I7PjtsPDQyO1BhZ2VMYXN0RW5hYmxlZDtpPDI%2bOz4%2bOz47Oz47Pj4 7dDxwPHA8bDxWaXNpYmxlOz47bDxvPGY％2bOz4％2bOz47bDxpPDE％2bO2k8Mz47aTw1PjtpPDc％2bOz47bDx0PHA8cDxsPFRleHQ7PjtsPDIxMDk7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPEVETXMgYW5kIEFtZW5kbWVudHM7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPDE7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPDUwOz4％2bOz47Oz47Pj47Pj47Pj47Pj47bDxfTWVudUN0cmw6X0dvVG87Pj5NHcFbPBNzNuwxs7sYLdUE2omkjw％3D％3D＆_MenuCtrl％3AddlSession = 875＆_MenuCtrl％3A_GoTo.x = 57＆_MenuCtrl％3A_GoTo.y = 14＆ddlStatus = 1＆ddlSortedBy = 1 P>

这是 IE 发送的 RAW 请求：

POST /EDMi/EDMList.aspx HTTP/1.1 接受：图片/gif、图片/jpeg、 图像/pjpeg，图像/pjpeg， 应用程序/x-shockwave-flash, 应用程序/xaml+xml， 应用程序/vnd.ms-xps 文档， 应用程序/x-ms-xbap， 应用程序/x-ms-应用程序， 应用程序/vnd.ms-excel， 应用程序/vnd.ms-powerpoint， 应用程序/msword，/ 引用者： http://edmi.parliament.uk/EDMi/EDMList.aspx 接受语言：en-gb 用户代理： Mozilla/4.0（兼容；MSIE 8.0； 视窗 NT 5.1；三叉戟/4.0； .NET CLR 1.1.4322； .NET CLR 2.0.50727； .NET CLR 3.0.04506.30； InfoPath.1； .NET CLR 3.0.04506.648； OfficeLiveConnector.1.3； OfficeLivePatch.0.0； .NET CLR 3.0.4506.2152； .NET CLR 3.5.30729) 内容类型： 应用程序/x-www-form-urlencoded 接受编码：gzip，放气主机： edmi.parliament.uk 内容长度： 2431 连接：保持活动编译指示： 无缓存 Cookie： WT_FPC=id=83.217.99.254-2364242496.30021299:lv=1249572414567:ss=1249572414567; ASP.NET_SessionId=vwxgo4rlex1j5m55l0bivrqo

__ EVENTTARGET =＆__ EVENTARGUMENT =＆__ VIEWSTATE = dDwxMDgyNzIxNDQ2O3Q8O2w8aTwzPjs％2BO2w8dDw7bDxpPDE％2BO2k8Mz47aTw1PjtpPDExPjs％2BO2w8dDw7bDxpPDEzPjtpPDE3Pjs％2BO2w8dDx0PHA8cDxsPERhdGFWYWx1ZUZpZWxkO0RhdGFUZXh0RmllbGQ7PjtsPFNFU1NJT05JRDtJVEVNX1ZBTFVFOz4％2BOz47dDxpPDIwPjtAPDA4LTA5OzA3LTA4OzA2LTA3OzA1LTA2OzA0LTA1OzAzLTA0OzAyLTAzOzAxLTAyOzAwLTAxOzk5LTAwOzk4LTk5Ozk3LTk4Ozk2LTk3Ozk1LTk2Ozk0LTk1OzkzLTk0OzkyLTkzOzkxLTkyOzkwLTkxOzg5LTkwOz47QDw4OTk7ODkxOzg4NTs4NzU7ODczOzY4Mjs2ODE7NjgwOzY3OTs3MDM7NzAyOzcwMTs3MDA7Njk5OzY5ODs2OTc7Njk2OzY5NTs2OTQ7NjkzOz4％2BOz47Oz47dDxwPGw8VGV4dDs％2BO2w8TGlzdCBPZiBFYXJseSBEYXkgTW90aW9uczs％2BPjs7Pjs％2BPjt0PDtsPGk8MT47aTwzPjs％2BO2w8dDx0PDs7bDxpPDA％2BOz4％2BOzs％2BO3Q8dDw7O2w8aTwwPjs％2BPjs7Pjs％2BPjt0PDtsPGk8MT47aTwzPjs％2BO2w8dDw7bDxpPDE％2BO2k8Mz47aTw1PjtpPDc％2BOz47bDx0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztFbmFibGVkO18hU0I7PjtsPDA7UGFnZUZpcnN0RGlzYWJsZWQ7bzxmPjtpPDI％2BOz4％2BOz47Oz47dDxwPHA8bDxDb21tYW5kQXJndW1lbnQ7Q3NzQ2xhc3M7RW5hYmxlZDtfIVNCOz47bDwtMTtQYWdlUHJldkRpc2FibGVkO 288Zj47aTwyPjs％2BPjs％2BOzs％2BO3Q8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO18hU0I7PjtsPDE7UGFnZU5leHRFbmFibGVkO2k8Mj47Pj47Pjs7Pjt0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztfIVNCOz47bDw0MjtQYWdlTGFzdEVuYWJsZWQ7aTwyPjs％2BPjs％2BOzs％2BOz4％2BO3Q8O2w8aTwxPjtpPDM％2BO2k8NT47aTw3Pjs％2BO2w8dDxwPHA8bDxUZXh0Oz47bDwyMTA5Oz4％2BOz47Oz47dDxwPHA8bDxUZXh0Oz47bDxFRE1zIGFuZCBBbWVuZG1lbnRzOz4％2BOz47Oz47dDxwPHA8bDxUZXh0Oz47bDwxOz4％2BOz47Oz47dDxwPHA8bDxUZXh0Oz47bDw1MDs％2BPjs％2BOzs％2BOz4％2BOz4％2BO3Q8O2w8aTwxPjtpPDM％2BOz47bDx0PDtsPGk8MT47aTwzPjtpPDU％2BO2k8Nz47PjtsPHQ8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO0VuYWJsZWQ7XyFTQjs％2BO2w8MDtQYWdlRmlyc3REaXNhYmxlZDtvPGY％2BO2k8Mj47Pj47Pjs7Pjt0PHA8cDxsPENvbW1hbmRBcmd1bWVudDtDc3NDbGFzcztFbmFibGVkO18hU0I7PjtsPC0xO1BhZ2VQcmV2RGlzYWJsZWQ7bzxmPjtpPDI％2BOz4％2BOz47Oz47dDxwPHA8bDxDb21tYW5kQXJndW1lbnQ7Q3NzQ2xhc3M7XyFTQjs％2BO2w8MTtQYWdlTmV4dEVuYWJsZWQ7aTwyPjs％ 2BPjs%2BOzs%2BO3Q8cDxwPGw8Q29tbWFuZEFyZ3VtZW50O0Nzc0NsYXNzO18hU0I7PjtsPDQyO1BhZ2VMYXN0RW5hYmxlZDtpPDI%2BOz4%2BOz47Oz47Pj4 7dDxwPHA8bDxWaXNpYmxlOz47bDxvPGY％2BOz4％2BOz47bDxpPDE％2BO2k8Mz47aTw1PjtpPDc％2BOz47bDx0PHA8cDxsPFRleHQ7PjtsPDIxMDk7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPEVETXMgYW5kIEFtZW5kbWVudHM7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPDE7Pj47Pjs7Pjt0PHA8cDxsPFRleHQ7PjtsPDUwOz4％2BOz47Oz47Pj47Pj47Pj47Pj47bDxfTWVudUN0cmw6X0dvVG87Pj5NHcFbPBNzNuwxs7sYLdUE2omkjw％3D％3D＆_MenuCtrl％3AddlSession = 885＆ddlStatus = 0＆ddlSortedBy = 1＆_MenuCtrl％3A_GoTo.x = 37＆_MenuCtrl％3A_GoTo.y = 12 P>

IE Header 似乎有一个额外的 cookie(WT_FPC=id=83.217.99.254-2364242496.30021299:lv=1249572414567:ss=1249572414567;) 女巫似乎通过 WebTrends Cookie 插件跟踪使用 cookie 的访问者。两个 POST 请求都返回 HTTP 状态代码 302 并重定向到返回状态 200 的 GET 请求。

有什么想法吗？

Answer 1

您每次都在创建一个新的 CookieContainer。 尝试使用索引页面请求的 CookieContainer 作为表单提交的容器，它应该包含额外的 cookie。或者，除了表单之外的其他东西可能会传递额外的 cookie。使用 IEinspector 的 HttpAnalyzer 或 Firefox 的 Firebug 检查页面何时加载，以确保其他表单元素（如图像）没有通过 cookie。

Answer 2

我已经破解了。 .NET 服务器似乎不喜欢我同时更改状态和会话。 如果我将“ddlStatus”更改为：

字符串 postdata = "__EVENTTARGET=&__EVENTARGUMENT=&__VIEWSTATE=" + viewState + "&_MenuCtrl%3AddlSession=" + sessionId + "&_MenuCtrl%3A_GoTo.x=57&_MenuCtrl%3A_GoTo.y=14&ddlStatus=1&ddlSortedBy=1";

到这里：

字符串 postdata = "__EVENTTARGET=&__EVENTARGUMENT=&__VIEWSTATE=" + viewState + "&_MenuCtrl%3AddlSession=" + sessionId + "&_MenuCtrl%3A_GoTo.x=57&_MenuCtrl%3A_GoTo.y=14&ddlStatus=0&ddlSortedBy=1";

我将不得不在第二个 POST 请求中更改 ddlStatus，对于表单中的每个更改，依此类推。 .NET 似乎受过很好的教育，一次只能吃一个甜食。

感谢大家的帮助:)

Answer 3

也许这与您的问题无关，但有时当您抓取网站时，远程服务器会识别出正在浏览的人是脚本并阻止某些操作。我通常通过将 UserAgent 属性设置为请求来解决此问题。这是一个糟糕的安全措施，但在我的经验中经常使用。

Here you can find some sample user agent strings.

Answer 4

该请求中唯一让我感到奇怪的是Expect 标头。 Apparently it's caused problems for people in the past。要停止这种情况，您可以使用以下行：

System.Net.ServicePointManager.Expect100Continue = false;

如果这是问题所在，可能值得将该属性设置回原来的状态，因为它是一个全局变量，很可能会影响代码的其他部分。