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Using cookies with HttpWebRequest

Posted on 2004-03-20
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Last Modified: 2007-12-19
I'm working on building a program that will log into a web site using cookies and extract data from the page. I'm using HttpWebRequest. I know there is a CookieContainer property but I haven't quite figured out how to get this to work yet. Ideally I'd like to be able to load the cookie data from a file on my computer and access the page using HttpWebRequest. Does anybody have some code samples I could try?
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Question by:alc
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LVL 12

Expert Comment

by:esteban_felipe
ID: 10643010
Hi alc,

You will have to follow these steps

1.- Make an HttpWebRequest and set yourRequest.CookieContainer = new CookieContainer.
2.- Point the request the login page and post login/password info.
3.- Set your httpwebresponse.cookies to request.CookieContainer.GetCookies(request.RequestUri)
4.- Store the cookies somewhere for later use
5.- For future requests add your stored cookies in the cookieContainer object of your request.



Esteban Felipe
www.estebanf.com
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Author Comment

by:alc
ID: 10643055
Esteban,

In step 2 you say to post the login/password info. I'm not quite sure how to do this. When I review the cookies on my computer I can see my user name and the encrypted password. Where does this information go in the Cookie? The Cookie object has a Value property but I'm not sure how this is used. Can you post some sample code that does this?
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LVL 12

Expert Comment

by:esteban_felipe
ID: 10643131
To post data you will need to:

string strPost="login=yourlogin&password=yourpassword";
HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(thetargeturlloginpage);
objRequest.CookieContainer = new CookieContainer();
objRequest.Method = "POST";
objRequest.ContentLength = strPost.Length;
objRequest.ContentType = "application/x-www-form-urlencoded";
StreamWriter writer = new StreamWriter(objRequest.GetRequestStream());
writer.write(strPost);
writer.close();
HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
objResponse.Cookies = objRequest.CookieContainer.GetCookies(objRequest.RequestUri);
foreach(Cookie cookie in objResponse.Cookies)
{
//Save to cookies. I would binary serialize to disk, but any method should work
}


the actual string to post will depend of your target page. You are supposed to send all data that would be send by a html form. So, check out the html source code and find what values it's expecting. For example if you find that the source code have something like:
Login = <input type="text" id="username">
password = <input type="password" id="userpassword">
remember me <input type="checkbox" id="rememberme">

you will have to post something like ="username=YOURUSERNAME&userpassword=YOURPASSWORd&rememberme=true"

In later request you would do


HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(thetargetpageurlthatrequireloggeduser);
objRequest.CookieContainer = new CookieContainer();
objRequest.CookieContainer.Add(YOURSAVEDCOOKIES); //if there's more than one, add them all
HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
//Work with objResponse from here.

Esteban Felipe
www.estebanf.com
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Author Comment

by:alc
ID: 10644213
Esteban,

That helped, but I'm still not getting the response I expected. I can see that I'm now getting cookies in the response. However, the response stream is empty. I'm not sure why this is. Any ideas?
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LVL 12

Expert Comment

by:esteban_felipe
ID: 10644600
Can i see your code please?
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Author Comment

by:alc
ID: 10645401
try
{

      HttpWebRequest oReq =
            (HttpWebRequest)WebRequest.Create("http://www.investors.com/login.asp?/register/default.asp?location=/member/checkup/checkup.asp?t=ge&ss=yes&survey=falsewinname=registrationend:;");
      oReq.CookieContainer = new CookieContainer();
      string strPost = "htmUserName=<username>&htmPassword=<password>";                  oReq.Method = "POST";
      oReq.ContentLength = strPost.Length;
      oReq.ContentType = "application/x-www-form-urlencoded";
      StreamWriter writer = new StreamWriter(oReq.GetRequestStream());
      writer.Write(strPost);
      writer.Close();

      HttpWebResponse oResp = (HttpWebResponse)oReq.GetResponse();
      oResp.Cookies = oReq.CookieContainer.GetCookies(oReq.RequestUri);

      // Print the properties of each cookie.
      foreach (Cookie cook in oResp.Cookies)
      {
            Debug.WriteLine("Cookie:");
            Debug.WriteLine(cook.Name + " = " + cook.Value);
            Debug.WriteLine("Domain: " + cook.Domain);
            Debug.WriteLine("Path: " + cook.Path);
            Debug.WriteLine("Port: " + cook.Port);
            Debug.WriteLine("Secure: " + cook.Secure);
   
            Debug.WriteLine("When issued: " + cook.TimeStamp);
            Debug.WriteLine("Expires: " + cook.Expires + " (expired? " + cook.Expired + ")");
            Debug.WriteLine("Don't save: " + cook.Discard);    
            Debug.WriteLine("Comment: " + cook.Comment);
            Debug.WriteLine("Uri for comments: " + cook.CommentUri);
            Debug.WriteLine("Version: RFC " + (cook.Version == 1 ? "2109" : "2965"));

            // Show the string representation of the cookie.
            Debug.WriteLine ("String: " + cook.ToString());
      }

      Stream oStream = oResp.GetResponseStream();
      Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
      StreamReader oStreamRead = new StreamReader( oStream, encode );

      WriteStream(oStreamRead);

      oResp.Close();
      oStreamRead.Close();
      oStream.Close();
}
catch(WebException e)
{
      Debug.WriteLine("Web Exception"+
            "\n\nException Message :" + e.Message);
      if(e.Status == WebExceptionStatus.ProtocolError)
      {
            Debug.WriteLine("Status Code : " + ((HttpWebResponse)e.Response).StatusCode);
            Debug.WriteLine("Status Description : " + ((HttpWebResponse)e.Response).StatusDescription);
      }
}

private void WriteStream(StreamReader oStreamRead)
{
      string strLine;

      while ((strLine = oStreamRead.ReadLine()) != null)
      {
            Debug.WriteLine(strLine);
      }

}
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LVL 12

Expert Comment

by:esteban_felipe
ID: 10646212
Questions:
1.- Do you get any cookie printed?
2.- What response are you getting and what response are you expecting to get?
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Author Comment

by:alc
ID: 10646432
1 - Yes, I get one cookie in the response.
2 - There is nothing in the Response Stream. The first ReadLine() is null.
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LVL 12

Expert Comment

by:esteban_felipe
ID: 10646454
uhmm... weird... Tell me something, ¿what's the normal behavior of that page? Is theres any chance that after you login you get a response.redirect?.
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Author Comment

by:alc
ID: 10646512
Yes, I think it is doing a response redirect. The URL changes once I login and another IE window is loaded with the page I want.
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Accepted Solution

by:
esteban_felipe earned 500 total points
ID: 10646525
Yeah, I saw it (I opened an account there for testing). Now I'm trying to figure out how to "get aware" of the redirect.

But this may be getting off topic. You have the cookie now, you should be able to access a "logged" page now. Did you tried that?
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Author Comment

by:alc
ID: 10646530
Yes, I tried accessing the page directly once I had the cookies but for some reason it didn't have any HTML. It only had a bunch of Javascript.
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