WinRT WebView and Cookies

Turns out that WebView Control in WinRT is much more limited than it’s counterpart in WPF/Silverlight.

There are some great articles out there in how to extend the control in order for it to support navigation events and some other features.

For a personal project I'm working on, I needed to grab cookies a Web Site generated for the user. Basically, after a user authenticated to a Web Site I needed to get the authentication cookies and generate some extra requests on her behalf.

In order to do so, I’ve found this great article about a similar case using SharePoint and Azure ACS.

The secret is to use a p/invoke to native InternetGetCookieEx to get cookies for the current URL displayed in the WebView control.

 

void WebView_LoadCompleted(object sender, NavigationEventArgs e)
{
    var urlPattern = "http://someserver.com/somefolder";
    if (e.Uri.ToString().StartsWith(urlPattern))
    {
        var cookies = InternetGetCookieEx(e.Uri.ToString());

        // Do something with the cookies
    }
}

static string InternetGetCookieEx(string url)
{
    uint sizeInBytes = 0;

    // Gets capacity length first
    InternetGetCookieEx(url, null, null, ref sizeInBytes, INTERNET_COOKIE_HTTPONLY, IntPtr.Zero);

    uint bufferCapacityInChars = (uint)Encoding.Unicode.GetMaxCharCount((int)sizeInBytes);

    // Now get cookie data
    var cookieData = new StringBuilder((int)bufferCapacityInChars);
    InternetGetCookieEx(url, null, cookieData, ref bufferCapacityInChars, INTERNET_COOKIE_HTTPONLY, IntPtr.Zero);

    return cookieData.ToString();
}

 

Function import using p/invoke follows:

const int INTERNET_COOKIE_HTTPONLY = 0x00002000;

[DllImport("wininet.dll", CharSet = CharSet.Unicode, SetLastError = true)]
static extern bool InternetGetCookieEx(string pchURL, string pchCookieName, StringBuilder pchCookieData, ref System.UInt32 pcchCookieData, int dwFlags, IntPtr lpReserved);

Enjoy!

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