简单易懂的Security Token Service实例以及介绍

首先我们来说说STS（Security Token Service）的最简生命周期，当然这是要基于WIF（Windows Identity Foundation）框架的。

一.  分析传入数据的可用性，并创建SignInRequestMessage

WSFederationMessage提供CreateFromUri以及CreateFromNameValueCollection等简单的创建入口（本例使用CreateFromUri）

二. 通过对SignInRequestMessage的解析以及确认，生成SignInResponseMessage

       1.创建SecurityTokenServiceConfiguration以驱动自定义SecurityTokenService 

                        a)自定义的SecurityTokenService需要对以下的内容进行定义：

                                         * ClaimsIdentity发布的内容（Claims的ClaimsType和Value需要搭建STS人自己定义）

                                         * Scope的定义

                         b) Scope无非是对请求STS端应用以及其他的Policy进行定义，其中SignedCertificate必须要进行定义。

       2.创建WSFederationSerializer以对SignInRequestMessage进行处理，并序列化SignInResponseMessage

       3.验证SignInRequestMessage 内容的有效性（如果STS使用的是Windows 身份验证，可以忽略此项）

       4. 获取验证过的自定义的Identity（或者系统Identity），结合SignInRequestMessage，通过自定义SecurityTokenService进行发布（Issue），获取RequestSecurityTokenResponse

       5. 获取最终的SignInResponseMessage

声明周期即以上的部分，这是最简单的方式，其余的需要进行自定义的部分，可以在这简单的实例基础上进行添加。

以下是代码部分

一. 自定义Security Token Service

public class CustomSTS : SecurityTokenService
    {
        private SigningCredentials _signingCreds;
        private EncryptingCredentials _encryptingCreds;
        public CustomSTS(SecurityTokenServiceConfiguration configuration) :base(configuration)
        {
            _signingCreds = new X509SigningCredentials(new X509Certificate2(@"C:\Users\Administrator\Desktop\ForNewSTS.pfx","1qaz2wsxE"));

            _encryptingCreds = new X509EncryptingCredentials(new X509Certificate2(@"C:\Users\Administrator\Desktop\ForNewSTS.pfx", "1qaz2wsxE"));
        }

        protected override Microsoft.IdentityModel.Claims.IClaimsIdentity GetOutputClaimsIdentity(Microsoft.IdentityModel.Claims.IClaimsPrincipal principal, Microsoft.IdentityModel.Protocols.WSTrust.RequestSecurityToken request, Scope scope)
        {
            ClaimsIdentity outputIdentity = new ClaimsIdentity();
            outputIdentity.Claims.Add(new Claim("http://test.com/c/c","/create"));
            return outputIdentity;
        }

        protected override Scope GetScope(Microsoft.IdentityModel.Claims.IClaimsPrincipal principal, Microsoft.IdentityModel.Protocols.WSTrust.RequestSecurityToken request)
        {
            Scope sc = new Scope(request.AppliesTo.Uri.AbsoluteUri, _signingCreds);
            sc.TokenEncryptionRequired = false;
            sc.ReplyToAddress = request.ReplyTo;
            return sc;
        }
    }

二. 生成SignInResponseMessage的简易流程

private SignInResponseMessage ProcessSignInRequest(SignInRequestMessage requestMessage)
        {
            // Ensure that the requestMessage has the required wtrealm parameter
            if (String.IsNullOrEmpty(requestMessage.Realm))
            {
                throw new InvalidOperationException("Missing realm");
            }

            //set the SecurityTokenService Configuration Name, this name should be unique.
            SecurityTokenServiceConfiguration stsconfig = new SecurityTokenServiceConfiguration("PassiveFlowSTS");

            // Create our STS backend
            SecurityTokenService sts = new CustomSTS(stsconfig);

            // Create the WS-Federation serializer to process the request and create the response
            WSFederationSerializer federationSerializer = new WSFederationSerializer();

            // Create RST from the request
            RequestSecurityToken request = federationSerializer.CreateRequest(requestMessage, new WSTrustSerializationContext());

            // Get RSTR from our STS backend
            RequestSecurityTokenResponse response = sts.Issue((IClaimsPrincipal)GenericAPrincipal(), request);

            // Create Response message from the RSTR
            return new SignInResponseMessage(new Uri(response.ReplyTo),
                    federationSerializer.GetResponseAsString(response, new WSTrustSerializationContext()));

        }

        public IClaimsPrincipal GenericAPrincipal() 
        {
            IClaimsIdentity localIdentity = new ClaimsIdentity("testFederation", "http://xxx.com/c/test", "somebody in STS");
           
            List list = new List();
            list.Add(localIdentity);
            ClaimsPrincipal p = new ClaimsPrincipal(list);
            return p;
        }