Using SharePoint Web Services using Forms Authentication

Scenario:

Solution:
Authentication Web service. It has a method named Login that, when called, places an authentication cookie in the proxy's System.Web.Services.Protocols.HttpWebClientProtocol.CookieContainer collection. That cookie can then be used in subsequent requests to other Web services in the site that is protected by forms authentication to authenticate the request.

For purposes of creating your Web service proxies (such as adding Web references in Visual Studio), use a Windows authentication–protected site. In most cases, the Visual Studio Add Web Reference wizard does not work with a SharePoint site that is protected by forms authentication.

Add a Web reference to the Authentication Web service in the site that is protected by forms authentication; the Authentication Web service can be found in the path http://servername/_vti_bin/authentication.asmx. Name this Web reference fbaAuth.

Code:

fbaAuth.Authentication auth = new fbaAuth.Authentication();

auth.CookieContainer = new System.Net.CookieContainer();
auth.AllowAutoRedirect = true;

fbaAuth.LoginResult lr = auth.Login("myUserName", "myUserPassword");

if (lr.ErrorCode == fbaAuth.LoginErrorCode.NoError)
{
  //Now we can talk to the Lists Web service.
fbaLists.Lists lists = new fbaLists.Lists();
// This is IMPORTANT for reusing the cookie
lists.CookieContainer = auth.CookieContainer;

   XmlNode xData = lists.GetListCollection();
}

Note:
By default, a zone that is configured to use forms authentication does not enable Client Integration features. This option, which is found on the Authentication Provider page in SharePoint Central Administration, must be turned on if you want to use the SharePoint Web services. When this option is turned off, SharePoint Products and Technologies also turn off support for remote interfaces, such as Web services.

To reuse this cookie, we need to set CookieContainer property for the Lists Web service proxy equal to the CookieContainer property of the Authentication Web service proxy.