基于角色的认证和授权

 

今天看了codeproject上面的一片文章，感觉不错。作者主要是用form authentication 实现了基于角色的认证。功能还算可以，基本可以代替MS 的Membership了，但是没有membership那么庞大。做一个基本的应用是够用了。

 

 

翻译一下大概内容，大意记录如下：

 

作者实现了4个网页，功能是：添加用户，给用户指定角色，删除角色，管理角色。

The Classes Overview

There are 4 classes: User, Role, SitePrincipal and SiteIdentity. I would like to overview the classes' methods and properties here:

The User class

User()	Default parameter less constructor to create a new user
User(int userID)	This constructor gets a userID and looks up the user details from the database
User(string email)	This constructor gets an email and looks up the user details from the database
GetUsers()	This method returns a DataSet of all the users available in the database
GetRoles()	This method returns a DataSet of roles assigned to the current user
GetUserRoles(int userID)	This static method grabs the userID and returns a roles ArrayList assigned to that user
AddToRole(int roleID)	This method assigns a role to the current user
RemoveFromRole(int roleID)	This method removes current user from the role that has been passed by the roleID.
Add()	Adds a new user to the database
Update()	Updates current user information
Delete()	Deletes current user
UserID	Gets/Sets user's id number
FullName	Gets/Sets user's full name
Email	Gets/Sets user's email
Password	Gets/Sets user's password
Biography	Gets/Sets user's biography
DateAdded	Gets/Sets user's registering date

The Role class

Role()	Default parameter less constructor to create a new role
Role(int roleID)	This constructor gets a roleID and looks up the role details from the database
GetRoles()	This method returns a DataSet of all roles available in the database
Add()	Adds a new role to the database
Update()	Updates current role information
Delete()	Deletes current role
RoleID	Gets/Sets role ID number
RoleName	Gets/Sets role name

The SitePrincipal class (implements the IIPrincipal Interface)

SitePrincipal(int userID)	This constructor gets a userID and looks up details from the database
SitePrincipal(string email)	This constructor gets an email and looks up details from the database
IsInRole()	(IIPrincipal.IsInRole()) Indicates whether a current principal is in a specific role
ValidateLogin()	Adds a new user to the database
Identity	(IIPrincipal.Identity) Gets/Sets the identity of the current principal
Roles	Gets the roles of the current principal

The SiteIdentity class (implements the IIdentity Interface)

SiteIdentity(int userID)	This constructor gets a userID and looks up the user details from the database
SiteIdentity(string email)	This constructor gets an email and looks up the user details from the database
AuthenticationType	(IIdentity.AuthenticationType) Always returns "Custom Authentication"
IsAuthenticated	(IIdentity.IsAuthenticated) Always returns true
Name	(IIdentity.Name) Gets the name of the current user
Email	Gets the email of the current user
Password	Gets the password of the current user
UserID	Gets the user ID number of the current user

Enabling Forms Authentication

为了实现ASP.NET Forms 认证,  web.config 文件配置如下:

<configuration>
     <system.web>
      <authentication mode="Forms">
            <forms name="RolesBasedAthentication" 
                path="/" 
                loginUrl="/Login.aspx" 
                protection="All" 
                timeout="30">
            </forms>
         </authentication>
     </system.web>
</configuration>

 

forms的name属性指定了浏览器的cookie名字，默认的名字是.aspxauth，但是当在相同的服务器中有好几个应用程序，就应当一个不同的名字。loginurl是登录页面。timeout指定了cookie的有效时间，单位是分钟。当然了，对于要保存的cookie就无效了。protection是cookie的保存方法：all意味着数据会被加密和验证。别的可以指定的值包括：none,encryption,validation.

 

表单认证一旦被指定，每次用户请求一个页面，表单就要检查浏览器的cookie值。如果找到了，user identify就会以FormsIdentity类的形式保存在cookie中，这个类包含了认证用户的如下信息：

AthenticationType - returns the value Forms

IsAthenticated - returns a boolean value indicating where the user was authenticated

Name - Indicates the name of an authenticated user

因为FormsIdentity类只包含了用户的name属性，但是我们往往需要大量的信息，而不止于Name。因此我就写了这个SiteIdentity类，它实现了IIdentity接口，包含了认证用户的更多信息。

 

Creating the Login Page

登录页面包含两个文本框让用户输入电子邮件和密码，也许还可以放一个选项框，让用户选择是否要保持永久cookie，最后放一个submit按钮，Onclick事件处理如下：

private void Submit_Click(object sender, System.EventArgs e)
{
      // call the ValidateLogin static method to
      // check if the email and password are correct
      // if correct the method will return a new user else return null
      SitePrincipal newUser = 
        SitePrincipal.ValidateLogin(Email.Text, Password.Text);

    if (newUser == null)
    {
        ErrorMessage.Text = "Login failed for " + Email.Text;
        ErrorMessage.Visible = true;
    }
    else
    {
        // assign the new user to the current context user
        Context.User = newUser;
        // set the cookie that contains the email address
        // the true value means the cookie will be set persisted
        FormsAuthentication.SetAuthCookie( Email.Text, true ); 
        // redirect the user to the home page
        Response.Redirect("Default.aspx");
    }
}

 

 

Authenticating User On Every Request

主要是实现了一个所有页面都要继承的基类，所有继承自它的页面都会包含我们自定义的SiteProcipal实例信息：

public class PageBase: System.Web.UI.Page
{
    public PageBase()
    {
    }

    protected override void OnInit(EventArgs e)
    {    
        base.OnInit(e);
        this.Load += new System.EventHandler(this.PageBase_Load);
    }    



    private void PageBase_Load(object sender, System.EventArgs e)
    { 
      if (Context.User.Identity.IsAuthenticated) 
      {
        if (!(Context.User is SitePrincipal))
        {
              SitePrincipal newUser = 
                new SitePrincipal( Context.User.Identity.Name );
              Context.User = newUser;
            }    
    }
    }
}

 

以后所有的页面都要继承自此页，而非System.Web.UI.Page，因此，如果此时想得到用户的信息就简单了：

if (Context.User.Identity.IsAuthenticated) 
{
    string name = ((SiteIdentity)Context.User.Identity).FullName;
    string email = ((SiteIdentity)Context.User.Identity).Email;
    string password = ((SiteIdentity)Context.User.Identity).Password;
    string userID = ((SiteIdentity)Context.User.Identity).UserID;
}

 
或者你可以查看当前用户的角色：

if (Context.User.Identity.IsAuthenticated) 
{
    // if user is not in the Site Admin role,
    // he/she will be redirected to the login page
    if (!((SitePrincipal)Context.User).IsInRole("Site Admin"))
        Response.Redirect("Login.aspx");
}
The Demo Application
下载地址如下：