使用HttpMoudle和IPrincipal实现自定义身份及权限认证

HttpContext.Current.User用户对象表示用户的安全上下文，代码当前即以该用户的名义运行，包括用户的标识（IIdentity）和它们所属的任何角色。所有用户对象都需要实现 IPrincipal 接口。(MSDN)

创建一个User类实现IIdentity接口 重写相应的方法
public class User : IIdentity
{
private int _id;
private string _userName;
private string _password;
private bool _isAuthenticated;
#region properties
public virtual int Id
{
get { return this._id; }
set { this._id = value; }
}
public virtual string UserName
{
get { return this._userName; }
set { this._userName = value; }
}
public virtual string Password
{
get { return this._password; }
set { this._password = value; }
}
//是否通过认证
public virtual bool IsAuthenticated
{
get { return this._isAuthenticated; }
set { this._isAuthenticated = value; }
}
//重写为用户ID
public virtual string Name
{
get
{
if (this._isAuthenticated)
return this._id.ToString();
else
return "";
}
}
public virtual string AuthenticationType
{
get { return "CuyahogaAuthentication"; }
}
public User()
{
this._id = -1;
this._isAuthenticated = false;
}
}

创建一个CuyahogaPrincipal类实现IPrincipal接口
public class CuyahogaPrincipal : IPrincipal
{
private User _user;
// 返回一个现实IIdentity接口的user对象
public IIdentity Identity
{
get { return this._user; }
}
// 当前用户是否属于指定角色 在以后的权限认证中可以使用 也可以使用User类中的相关方法来代替
public bool IsInRole(string role)
{
foreach (Role roleObject in this._user.Roles)
{
if (roleObject.Name.Equals(role))
return true;
}
return false;
}
///初始化 若user通过授权则创建
public CuyahogaPrincipal(User user)
{
if (user != null && user.IsAuthenticated)
{
this._user = user;
}
else
{
throw new SecurityException("Cannot create a principal without u valid user");
}
}
}

创建一个实现IHttpModule的AuthenticationModule类
public class AuthenticationModule : IHttpModule
{
private const int AUTHENTICATION_TIMEOUT = 20;

public AuthenticationModule()
{
}

public void Init(HttpApplication context)
{
context.AuthenticateRequest += new EventHandler(Context_AuthenticateRequest);
}

public void Dispose()
{
// Nothing here
}

//登录时 验证用户时使用
public bool AuthenticateUser(string username, string password, bool persistLogin)
{
//数据访问类
CoreRepository cr = (CoreRepository)HttpContext.Current.Items["CoreRepository"];
string hashedPassword = Encryption.StringToMD5Hash(password);
try
{
//通过用户名密码得到用户对象
User user = cr.GetUserByUsernameAndPassword(username, hashedPassword);
if (user != null)
{
user.IsAuthenticated = true;
//string currentIp = HttpContext.Current.Request.UserHostAddress;
//user.LastLogin = DateTime.Now;
//user.LastIp = currentIp;
// Save login date and IP 记录相关信息
cr.UpdateObject(user);更新用户授权通过信息
// Create the authentication ticket
HttpContext.Current.User = new CuyahogaPrincipal(user);  //通过授权
FormsAuthentication.SetAuthCookie(user.Name, persistLogin);
return true;
}
else
{
//log.Warn(String.Format("Invalid username-password combination: {0}:{1}.", username, password));
return false;
}
}
catch (Exception ex)
{
throw new Exception(String.Format("Unable to log in user '{0}': " + ex.Message, username), ex);
}
}

/// <summary>
/// Log out the current user.注销用户
/// </summary>
public void Logout()
{
if (HttpContext.Current.User != null && HttpContext.Current.User.Identity.IsAuthenticated)
{
FormsAuthentication.SignOut();
}
}

private void Context_AuthenticateRequest(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
if (app.Context.User != null && app.Context.User.Identity.IsAuthenticated)//若用户已经通过认证
{
CoreRepository cr = (CoreRepository)HttpContext.Current.Items["CoreRepository"];
int userId = Int32.Parse(app.Context.User.Identity.Name);
User cuyahogaUser = (User)cr.GetObjectById(typeof(User), userId);//得到对应的cuyahogaUser对象
cuyahogaUser.IsAuthenticated = true;
app.Context.User = new CuyahogaPrincipal(cuyahogaUser);//将通过标准窗体认证的user替换成CuyahogaUser, cuyahogaUser包含更多的信息
}
}
}

登录时
protected void btnLogin_Click(object sender, System.EventArgs e)
{
AuthenticationModule am = (AuthenticationModule)Context.ApplicationInstance.Modules["AuthenticationModule"];
if (this.txtUsername.Text.Trim().Length > 0 && this.txtPassword.Text.Trim().Length > 0)
{
try
{
if (am.AuthenticateUser(this.txtUsername.Text, this.txtPassword.Text, this.chkPersistLogin.Checked))
{
//通过认证
Context.Response.Redirect(Context.Request.RawUrl);
}
else
{
//认证失败
}
}
catch (Exception ex)
{
}
}
}

退出登录用
protected void btnLogout_Click(object sender, System.EventArgs e)
{
AuthenticationModule am = (AuthenticationModule)Context.ApplicationInstance.Modules["AuthenticationModule"];
am.Logout();
Context.Response.Redirect(Context.Request.RawUrl);
}

这样就实现了身份认证功能

然后可以方便的实现权限认证
在User类中实现相应的权限逻辑 如: 表示当前用户是否有权限浏览指定的节点
public bool CanView(Node node)
{
foreach (Permission p in node.NodePermissions)
{
if (p.ViewAllowed && IsInRole(p.Role))
{
return true;
}
}
return false;
}

在Page代码中嵌入验证代码即可
User CuyahogaUser =  this.User.Identity as User;
if(CuyahogaUser.CanView())
{
}

权限认证模块还是挺简单.
别忘了在web.config中对AuthenticationModule进行注册