How to pass cookies to HtmlAgilityPack or WebClient?

Question

I use this code to login:

CookieCollection cookies = new CookieCollection();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("example.com");
request.CookieContainer = new CookieContainer();
request.CookieContainer.Add(cookies);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
cookies = response.Cookies;

string getUrl = "example.com";
string postData = String.Format("my parameters");
HttpWebRequest getRequest = (HttpWebRequest)WebRequest.Create(getUrl);
getRequest.CookieContainer = new CookieContainer();
getRequest.CookieContainer.Add(cookies);
getRequest.Method = WebRequestMethods.Http.Post;
getRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0";
getRequest.AllowWriteStreamBuffering = true;
getRequest.ProtocolVersion = HttpVersion.Version11;
getRequest.AllowAutoRedirect = true;
getRequest.ContentType = "application/x-www-form-urlencoded";

byte[] byteArray = Encoding.ASCII.GetBytes(postData);
getRequest.ContentLength = byteArray.Length;
Stream newStream = getRequest.GetRequestStream();
newStream.Write(byteArray, 0, byteArray.Length);
newStream.Close();

HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
using (StreamReader sr = new StreamReader(getResponse.GetResponseStream(), Encoding.GetEncoding("windows-1251")))
{
        doc.LoadHtml(sr.ReadToEnd());
        webBrowser1.DocumentText = doc.DocumentNode.OuterHtml;
}

then I want to use HtmlWeb (HtmlAgilityPack) or Webclient to parse the HTML to HtmlDocument(HtmlAgilityPack).

My problem is that when I use:

WebClient wc = new WebClient();
webBrowser1.DocumentText = wc.DownloadString(site);

or

doc = web.Load(site);
webBrowser1.DocumentText = doc.DocumentNode.OuterHtml;

The login disappear so i think I must somehow pass the cookies.. Any suggestions?

Answer 1

Try caching cookies from previous response locally and resend them each web request as follows:

private CookieCollection cookieCollection;

...

    parserObject = new HtmlWeb
                {
                    AutoDetectEncoding = true,
                    PreRequest = request =>
                    {
                        if (cookieCollection != null)
                            cookieCollection.Cast<Cookie>()
                                .ForEach(cookie => request.CookieContainer.Add(cookie));
                        return true;
                    },
                    PostResponse = (request, response) => { cookieCollection = response.Cookies; }
                };

Answer 2

Check HtmlAgilityPack.HtmlDocument Cookies

Here is an example of what you're looking for (syntax not 100% tested, I just modified some class I usually use):

public class MyWebClient
{
    //The cookies will be here.
    private CookieContainer _cookies = new CookieContainer();

    //In case you need to clear the cookies
    public void ClearCookies() {
        _cookies = new CookieContainer();
    }

    public HtmlDocument GetPage(string url) {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "GET";

        //Set more parameters here...
        //...

        //This is the important part.
        request.CookieContainer = _cookies;

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        var stream = response.GetResponseStream();

        //When you get the response from the website, the cookies will be stored
        //automatically in "_cookies".

        using (var reader = new StreamReader(stream)) {
            string html = reader.ReadToEnd();
            var doc = new HtmlDocument();
            doc.LoadHtml(html);
            return doc;
        }
    }
}

Here is how you use it:

var client = new MyWebClient();
HtmlDocument doc = client.GetPage("http://somepage.com");

//This request will be sent with the cookies obtained from the page
doc = client.GetPage("http://somepage.com/another-page");

Note: If you also want to use POST method, just create a method similar to GetPage with the POST logic, refactor the class, etc.

Answer 3

There are some recommendations here: Using CookieContainer with WebClient class

However, it's probably just easier to keep using the HttpWebRequest and set the cookie in the CookieContainer:

• HTTPWebRequest and CookieContainer
• http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.cookiecontainer.aspx

The code looks something like this:

 // Create a HttpWebRequest
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(getUrl);

// Create the cookie container and add a cookie
request.CookieContainer = new CookieContainer();

// Add all the cookies
foreach (Cookie cookie in response.Cookies)
{
    request.CookieContainer.Add(cookie);
}

The second thing is that you don't need to download the site again, since you already have it from your web response and you're saving it here:

HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
using (StreamReader sr = new StreamReader(getResponse.GetResponseStream(), Encoding.GetEncoding("windows-1251")))
{
        webBrowser1.DocumentText = doc.DocumentNode.OuterHtml;
}

You should be able to just take the HTML and parse it with the HTML Agility Pack:

HtmlDocument doc = new HtmlDocument();
doc.LoadHtml(webBrowser1.DocumentText);

And that should do it... :)