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Access a Forms Based SharePoint Site's Web Service

, 10 Mar 2008 CPOL
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This article describes how to access the Web Services of a Forms baed authenticated SharePoint site.


SharePoint site provides built-in Web Services with which we can access the SharePoint Object Model. To access those Web Services, we need to provide credentials to the Web Service. But if the SharePoint site uses Form based authentication, you may get the error: “The request failed with HTTP status 403: Forbidden”. It’s because Form based authentication works in a different way than others. To work this problem out, you need to use another authentication mechanism in SharePoint which is cookie based.


To get the list of available Web Services, go to IIS and expand the SharePoint web application. Then, under the node _vti_bin:

In a Form based SharePoint site, to invoke a Web Service, the user must be authenticated with the Authentication.asmx Web Service. The Web Service will return the LoginResult object which specifies the authentication status. The Web Service will not generate any exception if the authentication fails; rather the return object LoginResult will contain the login status. If authentication is successful, then the Web Service will put the credential key in the Web Services’ cookie. But to put the credential to the Web Service’s cookie, we need to initialize the cookie container of the Web Service as:

AuthenticationWSObject.CookieContainer = new CookieContainer();

You can get the cookie as follows:

Cookie cookie = cookies[loginResult.CookieName];

If the Web Service is invoked after initializing the cookie container property, the cookie will be filled with the credential token. Now, we can set the cookie in another Web Service’s cookie to access the site.

The process is shown in the following figure:


Using the code

The given example is a desktop application with two web references to the SharePoint Web Services Authnectincation.asmx and Lists.asmx. So, put the two Web Service addresses in the textbox:



I faced a problem in accessing a SharePoint site with Forms based authentication. My ex-team lead Moim Hossain helped me to figure out the solution. So I personally thank him. I have taken for granted that someone will face the same problem and they may get help form this article.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Architect ImpleVista Aps
Denmark Denmark
Sohel has more than six years of experience in professional software development with extensive involvement in Web based Object-Oriented, Multi-Tiered application design and development. He's Familiar with Test Driven Development (TDD) and refactoring techniques as well as having expertise in architecturing large enterprise applications. He has Experience in working with Content Management System and Portal Management System tools like SharePoint, DotNetNuke, Ektron.
Over last few years, he’s involved in development with projects on Microsoft SharePoint and received Microsoft MVP for SharePoint Server Development in the year 2011 and 2012. Currently he's working in a software company located Copenhagen,Denmark on a project integrating SharePoint and SAP. You can read his popular blog at:

Comments and Discussions

QuestionSite in Windows Authentication PinmemberUdayaraju8-Feb-12 5:02 
Authentication auth = new Authentication();
AuthenticationMode authmode = auth.Mode();
LoginResult x = auth.Login("username", "password");
Here Mode is returning "Windows", and in x it says ErrorCode:NotInFormsAuthentication..
Can you please suggest how can we proceed further if it is the case?
GeneralMy vote of 5 PinmemberIlka Guigova13-Jan-12 12:24 
Questionsoap webservice refernce PinmemberAmit99097-Aug-11 21:02 
AnswerRe: soap webservice refernce Pinmemberdxs75316-Apr-14 0:23 
Questionhttps problem Pinmemberfleschgordon17-Apr-09 4:48 
AnswerRe: https problem PinmemberSohel_Rana17-Apr-09 6:46 
GeneralRe: https problem Pinmemberfleschgordon19-Apr-09 21:10 
GeneralRe: https problem Pinmemberfleschgordon24-Apr-09 4:40 
QuestionProblems while authenticating other web services PinmemberMember 30575614-Jun-08 3:30 
AnswerRe: Problems while authenticating other web services PinmemberSohel_Rana4-Jun-08 18:34 
GeneralRe: Problems while authenticating other web services PinmemberMember 30575614-Jun-08 20:05 
GeneralRe: Problems while authenticating other web services PinmemberSohel_Rana5-Jun-08 1:42 
GeneralRe: Problems while authenticating other web services Pinmembervenukata11-May-10 1:13 
GeneralRe: Problems while authenticating other web services PinmemberSohel_Rana11-May-10 1:26 
GeneralThanks PinmemberPrabs29-Apr-08 17:47 
GeneralGood Job!!! PinmemberMember 437329311-Apr-08 19:39 
GeneralNot able to redirect to login or any specified page Pinmembersonashish26-Mar-08 17:19 
GeneralRe: Not able to redirect to login or any specified page Pinmembersonashish27-Mar-08 20:22 
GeneralRe: Not able to redirect to login or any specified page PinmemberSohel_Rana30-Mar-08 22:30 
GeneralConnection Error PinmemberJohn Dooner10-Mar-08 7:28 
GeneralRe: Connection Error PinmemberSohel_Rana12-Mar-08 5:54 

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