asp.net - 使用 HtppWebRequest 发布的表单数据无效

Question

我遇到了一个看起来很简单的网站，我非常有信心能够使用 HttpWebRequest 读取其数据，并且能够执行 GET 和 POST 请求。 GET 请求工作正常。 POST 请求也不会生成任何错误，但发布的表单数据仍然对返回的结果没有影响。发布的表单数据具有根据日期过滤数据的字段，但无论每个必需的数据都已发布，返回的数据都不会被过滤。我已经添加了每个 header 、表单数据，并在请求中添加了 cookie。

网页的 URL 是 http://www.bseindia.com/corporates/Insider_Trading_new.aspx?expandable=0

这看起来是一个非常普通的网站，但由于它是一个 aspx 页面，并且涉及 ViewState 和事件验证，因此预计这不会很容易。

我的第一步是使用 Fiddler 分析网站的 GET 和 POST，这让我感到惊讶，因为 Fiddler 没有捕获该 url 的任何流量。我已经尝试过查尔斯，但它本身并没有捕获这个网址。除此之外，Url Fiddler 和 Charles 都在捕获其他所有内容。我还想提一下，当我使用 HttpWebRequest 从控制台应用程序调用 Url 时，Fiddler 和 Charles 都捕获了它，但他们没有从 Chrome、FireFox 和 Internet Explorer 11 捕获它。

因此，我使用 FireFox 中的开发人员工具分析了网络事件，所有内容都可见，包括( header 、参数和 Cookie)。 Chrome 中不存在 cookie。当我通过创建 HttpWebRequest 检查 cookie 并得到响应时，没有 cookie 存在。所以这个网站真的很奇怪。

我设法创建了一个简单的函数来创建请求并获取响应。我正在做的是，我首先创建一个 GET 请求，获取网站字符串并从中提取 Viewstate、EventValidation 等。我使用此信息在第二个 HttpWebRequest 中使用，这是一个帖子。现在一切正常，我得到了回应，但没有达到预期。我想要两个给定日期之间的记录，并且我已在表单数据中指定了这些日期，但 POST 请求仍然不返回过滤后的数据。我已经提到了我在下面创建的函数，我将非常感谢任何关于为什么会发生这种情况以及如何处理这种情况的建议。理解这一点对我来说是一个挑战，因为我无法理解为什么这个简单的网站没有出现在 Fiddler 中。 (这使用了 Javascript 回发)

代码可能看起来又长又吓人，但它非常简单直接。

Try

        ' First GET Request to obtain Viewstate, Eventvalidation etc
        Dim objRequest2 As Net.HttpWebRequest = DirectCast(HttpWebRequest.Create("http://www.bseindia.com/corporates/Insider_Trading_new.aspx?expandable=0"), HttpWebRequest)
        objRequest2.Method = "GET"
        objRequest2.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"
        objRequest2.Headers.Add("Accept-Encoding", "gzip, deflate")
        objRequest2.Headers.Add("Accept-Language", "en-GB,en-US;q=0.8,en;q=0.6,ur;q=0.4")
        objRequest2.KeepAlive = True
        objRequest2.ContentType = "application/x-www-form-urlencoded"
        objRequest2.Host = "www.bseindia.com"
        objRequest2.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36"

        objRequest2.AutomaticDecompression = DecompressionMethods.Deflate Or DecompressionMethods.GZip

        Dim LoginRes2 As Net.HttpWebResponse
        Dim sr2 As IO.StreamReader
        LoginRes2 = objRequest2.GetResponse()

        sr2 = New IO.StreamReader(LoginRes2.GetResponseStream)
        Dim getString As String = sr2.ReadToEnd()
        Dim getCookieCollection = objRequest2.CookieContainer

        ' get the page ViewState                
        Dim viewStateFlag As String = "id=""__VIEWSTATE"" value="""
        Dim i As Integer = getString.IndexOf(viewStateFlag) + viewStateFlag.Length
        Dim j As Integer = getString.IndexOf("""", i)
        Dim viewState As String = getString.Substring(i, j - i)

        ' get page EventValidation                
        Dim eventValidationFlag As String = "id=""__EVENTVALIDATION"" value="""
        i = getString.IndexOf(eventValidationFlag) + eventValidationFlag.Length
        j = getString.IndexOf("""", i)
        Dim eventValidation As String = getString.Substring(i, j - i)

        ' get page EventValidation                
        Dim viewstateGeneratorFlag As String = "id=""__VIEWSTATEGENERATOR"" value="""
        i = getString.IndexOf(viewstateGeneratorFlag) + viewstateGeneratorFlag.Length
        j = getString.IndexOf("""", i)
        Dim viewStateGenerator As String = getString.Substring(i, j - i)

        viewState = System.Web.HttpUtility.UrlEncode(viewState)
        eventValidation = System.Web.HttpUtility.UrlEncode(eventValidation)

        Dim LoginRes As Net.HttpWebResponse
        Dim sr As IO.StreamReader
        Dim objRequest As Net.HttpWebRequest

        ' Second POST request to post the form data along with cookies
        objRequest = DirectCast(HttpWebRequest.Create("http://www.bseindia.com/corporates/Insider_Trading_new.aspx?expandable=0"), HttpWebRequest)

        Dim formDataCollection As New NameValueCollection

        formDataCollection.Add("__EVENTTARGET", "")
        formDataCollection.Add("__EVENTARGUMENT", "")
        formDataCollection.Add("__VIEWSTATE", viewState)
        formDataCollection.Add("__VIEWSTATEGENERATOR", viewStateGenerator)
        formDataCollection.Add("__EVENTVALIDATION", eventValidation)
        formDataCollection.Add("fmdate", "20160104")
        formDataCollection.Add("eddate", "20160204")
        formDataCollection.Add("hidCurrentDate", "2016/02/04")
        formDataCollection.Add("ctl00_ContentPlaceHolder1_hdnCode", "")
        formDataCollection.Add("txtDate", "04/01/2016")
        formDataCollection.Add("ddlCalMonthDiv3", "1")
        formDataCollection.Add("ddlCalYearDiv3", "2016")
        formDataCollection.Add("txtTodate", "04/02/2016")
        formDataCollection.Add("ddlCalMonthDiv4", "2")
        formDataCollection.Add("ddlCalYearDiv4", "2016")
        formDataCollection.Add("Hidden1", "")
        formDataCollection.Add("ctl00_ContentPlaceHolder1_GetQuote1_smartSearch", "Enter Security Name / Code / ID")
        formDataCollection.Add("btnSubmit.x", "44")
        formDataCollection.Add("btnSubmit.y", "2")

        Dim strFormdata As String = formDataCollection.ToString()
        Dim encoding As New ASCIIEncoding
        Dim postBytes As Byte() = encoding.GetBytes(strFormdata)

        objRequest.Method = "POST"
        objRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"
        objRequest.Headers.Add("Accept-Encoding", "gzip, deflate")
        objRequest.Headers.Add("Accept-Language", "en-GB,en-US;q=0.8,en;q=0.6,ur;q=0.4")
        objRequest.Headers.Add("Cache-Control", "private, max-age=60")
        objRequest.KeepAlive = True
        objRequest.ContentType = "application/x-www-form-urlencoded"
        objRequest.Host = "www.bseindia.com"
        objRequest.Headers.Add("Origin", "http://www.bseindia.com")
        objRequest.Referer = "http://www.bseindia.com/corporates/Insider_Trading_new.aspx?expandable=0"
        objRequest.Headers.Add("Upgrade-Insecure-Requests", "1")
        objRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36"

        objRequest.ContentType = "text/html; charset=utf-8"
        objRequest.Date = "Thu, 04 Feb 2016 13:42:04 GMT"
        objRequest.Headers.Add("Server", "Microsoft-IIS/8.0")
        objRequest.Headers.Add("Vary", "Accept-Encoding")
        objRequest.Headers.Add("X-AspNet-Version", "2.0.50727")
        objRequest.Headers.Add("ASP.NET", "ASP.NET")

        objRequest.AutomaticDecompression = DecompressionMethods.Deflate Or DecompressionMethods.GZip

        Dim gaCookies As New CookieContainer()

        Dim cookie1 As New Cookie("__asc", "f673f0d5152a823bc335f575d34")
        cookie1.Domain = ".bseindia.com"
        cookie1.Path = "/"
        gaCookies.Add(cookie1)

        Dim cookie2 As New Cookie("__auc", "f673f0d5152a823bc335f575d34")
        cookie2.Domain = ".bseindia.com"
        cookie2.Path = "/"
        gaCookies.Add(cookie2)

        Dim cookie3 As New Cookie("__utma", "253454874.280640365.1454519857.1454519865.1454519865.1")
        cookie3.Domain = ".bseindia.com"
        cookie3.Path = "/"
        gaCookies.Add(cookie3)

        Dim cookie4 As New Cookie("__utmb", "253454874.1.10.1454519865")
        cookie4.Domain = ".bseindia.com"
        cookie4.Path = "/"
        gaCookies.Add(cookie4)

        Dim cookie5 As New Cookie("__utmc", "253454874")
        cookie5.Domain = ".bseindia.com"
        cookie5.Path = "/"
        gaCookies.Add(cookie5)

        Dim cookie6 As New Cookie("__utmt", "1")
        cookie6.Domain = ".bseindia.com"
        cookie6.Path = "/"
        gaCookies.Add(cookie6)

        Dim cookie7 As New Cookie("__utmz", "253454874.1454519865.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)")
        cookie7.Domain = ".bseindia.com"
        cookie7.Path = "/"
        gaCookies.Add(cookie7)

        Dim cookie8 As New Cookie("_ga", "GA1.2.280640365.1454519857")
        cookie8.Domain = ".bseindia.com"
        cookie8.Path = "/"
        gaCookies.Add(cookie8)

        Dim cookie9 As New Cookie("_gat", "1")
        cookie9.Domain = ".bseindia.com"
        cookie9.Path = "/"
        gaCookies.Add(cookie9)

        Dim postStream As Stream = objRequest.GetRequestStream()
        postStream.Write(postBytes, 0, postBytes.Length)
        postStream.Flush()
        postStream.Close()

        LoginRes = objRequest.GetResponse()
        sr = New IO.StreamReader(LoginRes.GetResponseStream)

        ReadWebsite = sr.ReadToEnd()

        sr.Close()
        sr = Nothing
        LoginRes.Close()
        LoginRes = Nothing
        objRequest = Nothing
        Exit Function

    Catch ex As Exception
        ReadWebsite = Nothing
    End Try

注意:(没有 View 状态和事件验证的日期的原始表单数据)

日期:20160130编辑日期:20160205hid当前日期:2016/02/05ctl00_ContentPlaceHolder1_hdn代码:txt日期:04/01/2016ddlCalMonthDiv3:1ddlCalYearDiv3:2016txt日期:04/02/2016ddlCalMonthDiv4:2ddlCalYearDiv4:2016隐藏1:ctl00_ContentPlaceHolder1_GetQuote1_smartSearch:输入证券名称/代码/IDbtnSubmit.x:55btnSubmit.y:13

Answer 1

您可以考虑在浏览器中运行站点并使用工具来控制浏览器，而不是直接发出 GET/POST 请求。这可能比您当前的方法更容易、更稳健。

例如Selenium Web 驱动程序 http://www.seleniumhq.org/projects/webdriver/

您将加载页面，设置表单字段的值(使用 css 样式选择器查找适当的字段)，然后单击按钮。您可以自动化所有这些并获取页面源(不幸的是，我认为在 javascript 运行后，您无法获取当前状态下的完整 html，但您可能可以使用 api 来获取所需的元素)。

API文档:http://seleniumhq.github.io/selenium/docs/api/dotnet/