Delete Cookies from a Different Domain

Question

I am working on a web automation tool. After the tool is run once the associated website creates cookies that break the automation if I try to run it again. Because of this I would like to delete the cookies before the automation starts. I do not have access to the domain that actually creates the cookies. Is this possible? I know how to manipulate cookies, but all of that logic fails when you try to access cookies from a different website.

Additionally, I do not want to create a WebBrowser control if I can avoid it. I am trying to do everything with httpWebRequests so that it looks nicer.

Answer 1

If your test environment is running on a Windows system (and it sounds like it is) you can use pInvoke to manipulate the cache. The following four methods are needed. Unfortunately the code is owned by the company I work for, not me, so I can't paste it all here. It involves iterating over entries in the cache using "FindFirstUrlCacheEntry" and "FindNextUrlCacheEntry". Check the cache entry to see if it is a cookie and if it belongs to the domain you're interested in, if it is you can delete it.

[DllImport (@"wininet", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr FindFirstUrlCacheEntry ([MarshalAs (UnmanagedType.LPTStr)] string searchPattern, IntPtr ptrCacheEntryInfo, ref int cacheEntryInfoSize);

[DllImport (@"wininet", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern bool FindNextUrlCacheEntry (IntPtr ptrCacheHandler, IntPtr ptrCacheEntryInfo, ref int cacheEntryInfoSize);

[DllImport (@"wininet", SetLastError = true, CallingConvention = CallingConvention.StdCall)]
private static extern bool FindCloseUrlCache (IntPtr ptrCacheEntryInfo);

[DllImport ("wininet.dll", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern bool DeleteUrlCacheEntry (IntPtr lpszUrlName);

Answer 2

You should not be able to remove the cookie put by a website X using a http request comming from somewhere else than X.

You have 2 possibilities:

• You use the automatation tool to automate the removal of the cookie from the browser UI.
• You fake beeing the website X by changing the ip related to the x domain in your local cache (or by another mean).

Answer 3

I ended up just clearing all the cookies. There shouldn't be many the way that the server is set up, so it really will not be an issue. Running through every cookie was the only way that it worked for me. I get errors about my privilege level when I just try to delete the folder.

    private void ClearCookies()
    {
        string[] theCookies = System.IO.Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.Cookies));

        foreach (string currentFile in theCookies)
        {
            try
            {
                System.IO.File.Delete(currentFile);
            }
            catch (Exception ex) { }
        }
    }