Https form post using Httpwebrequest brings back the same page.

  • Thread starter Thread starter nganapat
  • Start date Start date
N

nganapat

I am trying to post form values to a https web page programmatically
using Httpwebrequest but no matter what I do the same login page is
returned instead of the next page. I would very much appreciate if
someone could show me what is it that I am doing wrong. Below is the
code that I am using.

string viewstate = HttpUtility.UrlEncode(viewstatevalue);
StringBuilder data = new StringBuilder();
data.Append("VAM_Group=");
data.Append("&__VIEWSTATE=" + viewstate);
data.Append("&ctlSignon:txtUserID=userid");
data.Append("&ctlSignon:txtPassword=password");
data.Append("&ctlSignon:ddlSignonDestination=");
data.Append("&ctlSignon:chkMakeDefaultPage=on");
data.Append("&ctlSignon:btnLogin=Login");
data.Append("&TestJavaScript=OK");

byte[] bBuffer;
bBuffer = Encoding.UTF8.GetBytes(data.ToString());

HttpWebRequest req =

(HttpWebRequest)WebRequest.Create("https://online.texanscu.org/texans/login.aspx");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = bBuffer.Length;
req.Credentials = CredentialCache.DefaultCredentials;
req.KeepAlive = true;
req.CookieContainer = new CookieContainer();

Stream swOut = req.GetRequestStream();
swOut.Write(bBuffer,0,bBuffer.Length);

HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
Stream sr = resp.GetResponseStream();
string result = new StreamReader(sr).ReadToEnd();

return result;
 
Thus wrote (e-mail address removed),
I am trying to post form values to a https web page programmatically
using Httpwebrequest but no matter what I do the same login page is
returned instead of the next page. I would very much appreciate if
someone could show me what is it that I am doing wrong. Below is the
code that I am using. [...]
(HttpWebRequest)WebRequest.Create("https://online.texanscu.org/texans/
login.aspx");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = bBuffer.Length;
req.Credentials = CredentialCache.DefaultCredentials;
Click to expand...

This is only meaningful for Windows Authentication. Your site seems to be
using Forms Authentication -- you already send username and password as form
data.
req.KeepAlive = true;
req.CookieContainer = new CookieContainer();
Click to expand...

Note that you should one CookieContainer instance throughout the entire HTTP
message exchange. If you create a CookieContainer for each request, you throw
away your previously received session and authentication cookies.


Cheers,
 
Joerg,

Thanks a lot for your reply. I understand that when I write
req.CookieContainer = new CookieContainer(); it creates a new
CookieContainer for each request. I am new to this. I would very much
appreciate if you could show me how to create one CookieContainer
instance throughout the entire HTTP message exchange. Thank you once
again.

NeelG

Joerg said:
Thus wrote (e-mail address removed),
I am trying to post form values to a https web page programmatically
using Httpwebrequest but no matter what I do the same login page is
returned instead of the next page. I would very much appreciate if
someone could show me what is it that I am doing wrong. Below is the
code that I am using. [...]
(HttpWebRequest)WebRequest.Create("https://online.texanscu.org/texans/
login.aspx");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = bBuffer.Length;
req.Credentials = CredentialCache.DefaultCredentials;
Click to expand...

This is only meaningful for Windows Authentication. Your site seems to be
using Forms Authentication -- you already send username and password as form
data.
req.KeepAlive = true;
req.CookieContainer = new CookieContainer();
Click to expand...

Note that you should one CookieContainer instance throughout the entire HTTP
message exchange. If you create a CookieContainer for each request, you throw
away your previously received session and authentication cookies.


Cheers,
Click to expand...
 
Thus wrote (e-mail address removed),
Joerg,

Thanks a lot for your reply. I understand that when I write
req.CookieContainer = new CookieContainer(); it creates a new
CookieContainer for each request. I am new to this. I would very much
appreciate if you could show me how to create one CookieContainer
instance throughout the entire HTTP message exchange. Thank you once
again.
Click to expand...

Simply make that CookieContainer a field of your HTTP client class, e.g.

class HttpClient
{
private CookieContainer cookieContainer = new CookieContainer();

// Your methods...
}

In your method, assign this.cookieContainer to HttpWebReqest.CookieContainer
for each request you send.

Cheers,
 
I tried what you suggested and that did not work. I am inserting the
whole code that I have in my form (I have created a windows application
- the form has a textbox and a button). Please let me know what I have
done wrong.

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private CookieContainer cookiejar = new CookieContainer();

public string ScrapeURL(string URL)
{
string viewstate = HttpUtility.UrlEncode(viewstatevalue);
StringBuilder data = new StringBuilder();
data.Append("VAM_Group=");
data.Append("&__VIEWSTATE=" + viewstate);
data.Append("&ctlSignon:txtUserID=userid");
data.Append("&ctlSignon:txtPassword=password");
data.Append("&ctlSignon:ddlSignonDestination=");
data.Append("&ctlSignon:chkMakeDefaultPage=on");
data.Append("&ctlSignon:btnLogin=Login");
data.Append("&TestJavaScript=OK");

byte[] bBuffer;

bBuffer = Encoding.UTF8.GetBytes(data.ToString());

HttpWebRequest req =
(HttpWebRequest)WebRequest.Create(URL);
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = bBuffer.Length;
req.Credentials = CredentialCache.DefaultCredentials;
req.KeepAlive = true;
req.CookieContainer = this.cookiejar;

Stream swOut = req.GetRequestStream();
swOut.Write(bBuffer,0,bBuffer.Length);

HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
Stream sr = resp.GetResponseStream();
string result = new StreamReader(sr).ReadToEnd();

return result;
}

private void button1_Click(object sender, EventArgs e)
{
textBox1.Text =
ScrapeURL("https://online.texanscu.org/texans/login.aspx");
}
}

I appreciate your help.

Thanks,
NeelG
 
Thus wrote (e-mail address removed),
I tried what you suggested and that did not work. I am inserting the
whole code that I have in my form (I have created a windows
application - the form has a textbox and a button). Please let me know
what I have done wrong.
Click to expand...

You should capture the HTTP traffic between browser and server using a browser
plugin and program your web requests accordingly. Maybe you're missing a
cookie that the web site issues before you hit the login page, or maybe the
site expects you to to send a User-Agent header, etc.

And sending a previously captured ASP.NET view state in your first requests
seems pretty wrong. You should send the view state received at runtime

Cheers,
 
Thanks for your help. I figured it out, I had to urlencode the field
names and now it works.

Thanks,
NeelG
 
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