Vb.net 按顺序相互依赖的多个httprequest

我正在将一个VBScript转换为VB.Net，我在处理web请求时挂断了

我已经读到我不需要MSXML2.XMLHTTP对象，但在VB.Net中执行webrequest似乎要复杂得多

VBScript源（未给出实际URL和post字符串）：

这样就可以工作了，并返回一个漂亮的JSON字符串和结果。需要注意的几点：

• 第一个请求“让您登录”。不知道这是怎么回事，只是在Fiddler中注意到，当你访问这个站点时，它会将你重定向到那个URL，然后你跳回去。它与我的公司单一登录有某种联系。但是，没有它脚本就无法工作
• 第二个请求实际上运行搜索
• 第三个请求以JSON字符串的形式从不同的URL提取结果，这正是我最终想要的
• 实际的“站点”由几个框架组成。一个框架是构建第二个请求的webform。另一个框架使用来自第三个请求的JSON以良好的格式拉/显示结果

我试着在这里使用这个函数：按顺序运行这些请求，但它不起作用。我认为这是因为每次调用函数时，它都会生成一个新的HTTPRequest

我认为这和cookies to有关，但也不清楚它在vb.net中是如何工作的

TL；如何将上述脚本转换为vb.net

另外，为什么在VB.Net中要复杂得多？我本以为这会更容易，哈哈。

在这个例子中尝试使用这个类。它使用WebRequest类处理您引用的示例中的大部分代码

    Dim objWebClient As New WebClient()

    objWebClient.DownloadString(sLoginUrl)

    objWebClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded")
    objWebClient.UploadString(sResultsURL, "POST", sFormData)

    objWebClient.DownloadString(sResultsHandlerURL)

---

我在我的帖子上得到了克劳科德的建议。我在帖子中的链接中修改了该函数，如下所示：

Function WRequest(URL As String, method As String, POSTdata As String, ByRef cookieJar As CookieContainer) As String
    Dim responseData As String = ""
    Try

        Dim hwrequest As Net.HttpWebRequest = Net.WebRequest.Create(URL)
        hwrequest.CookieContainer = cookieJar
        hwrequest.Accept = "*/*"
        hwrequest.AllowAutoRedirect = True
        hwrequest.UserAgent = "http_requester/0.1"
        hwrequest.Timeout = 60000
        hwrequest.Method = method
        If hwrequest.Method = "POST" Then
            hwrequest.ContentType = "application/x-www-form-urlencoded"
            Dim encoding As New ASCIIEncoding() 'Use UTF8Encoding for XML requests
            Dim postByteArray() As Byte = encoding.GetBytes(POSTdata)
            hwrequest.ContentLength = postByteArray.Length
            Dim postStream As IO.Stream = hwrequest.GetRequestStream()
            postStream.Write(postByteArray, 0, postByteArray.Length)
            postStream.Close()
        End If
        Dim hwresponse As Net.HttpWebResponse = hwrequest.GetResponse()
        If hwresponse.StatusCode = Net.HttpStatusCode.OK Then
            Dim responseStream As IO.StreamReader = _
              New IO.StreamReader(hwresponse.GetResponseStream())
            responseData = responseStream.ReadToEnd()
        End If
        hwresponse.Close()
    Catch e As Exception
        responseData = "An error occurred: " & e.Message
    End Try
    Return responseData
End Function

Dim cookieJar As New CookieContainer

WRequest(sLoginURL, "GET", "", cookieJar)
WRequest(sResultsURL, "POST", postString, cookieJar)
Debug.Print(WRequest(sResultsHandlerURL, "GET", "", cookieJar))

然后称之为：

Function WRequest(URL As String, method As String, POSTdata As String, ByRef cookieJar As CookieContainer) As String
    Dim responseData As String = ""
    Try

        Dim hwrequest As Net.HttpWebRequest = Net.WebRequest.Create(URL)
        hwrequest.CookieContainer = cookieJar
        hwrequest.Accept = "*/*"
        hwrequest.AllowAutoRedirect = True
        hwrequest.UserAgent = "http_requester/0.1"
        hwrequest.Timeout = 60000
        hwrequest.Method = method
        If hwrequest.Method = "POST" Then
            hwrequest.ContentType = "application/x-www-form-urlencoded"
            Dim encoding As New ASCIIEncoding() 'Use UTF8Encoding for XML requests
            Dim postByteArray() As Byte = encoding.GetBytes(POSTdata)
            hwrequest.ContentLength = postByteArray.Length
            Dim postStream As IO.Stream = hwrequest.GetRequestStream()
            postStream.Write(postByteArray, 0, postByteArray.Length)
            postStream.Close()
        End If
        Dim hwresponse As Net.HttpWebResponse = hwrequest.GetResponse()
        If hwresponse.StatusCode = Net.HttpStatusCode.OK Then
            Dim responseStream As IO.StreamReader = _
              New IO.StreamReader(hwresponse.GetResponseStream())
            responseData = responseStream.ReadToEnd()
        End If
        hwresponse.Close()
    Catch e As Exception
        responseData = "An error occurred: " & e.Message
    End Try
    Return responseData
End Function

Dim cookieJar As New CookieContainer

WRequest(sLoginURL, "GET", "", cookieJar)
WRequest(sResultsURL, "POST", postString, cookieJar)
Debug.Print(WRequest(sResultsHandlerURL, "GET", "", cookieJar))

---

比VBS更复杂，哈哈，但它能工作

您需要在第一个请求上设置CookieContainer，然后在发出第二个请求时使用CookieContainer的相同实例。是一个用C#演示类似事情的示例。很抱歉格式化，它并没有完全从我以前的博客中完整地出现。这就成功了，修改了我链接中的函数，向ByRef传递了一个cookie容器，它成功了。在下面发布最终解决方案。谢谢不走运。看起来应该行得通，但不行。一定是关于饼干的处理方法。我从上面听从了克劳科德的建议，结果成功了。在下面发布了完整的解决方案。