带有 LINQ to SQL 的 ASP.NET MVC：如何实现对存储库中实体的授权？

Question

考虑到领域驱动设计，您将如何在存储库中实现用户授权？具体来说，您将如何限制用户提供的登录名可以看到哪些数据？

假设我们有一个存储产品的电子商务商城，其中只有部分产品由任何给定的商店经理维护。在这种情况下，任何给定的登录名都不应看到所有产品。

问题：

1. 您会选择存储库中的所有产品，然后使用过滤器来限制退回的产品吗？ 像 GetProducts("keyword:boat").restrictBy("myusername") 一样？
2. 您会从存储库中的控制器上下文中读取登录信息并被动地过滤结果吗？
3. 您将如何存储用户角色与其可以访问的实体之间的关系？您是否会简单地将实体键和角色存储在多对多表中，并为每个商店经理可以访问的每种产品保留一条记录？

代码示例或代码示例的链接会很棒。谢谢。

Answer 1

我采取的策略是在控制器操作上使用属性，该属性检查当前用户与所请求的实体之间的关系，然后根据查找结果允许或禁止该操作。我有几个不同的属性，具体取决于它是通过连接表还是具有直接关系。它使用反射来获取和检查值是否匹配，在我的例子中是数据上下文，但在您的存储库中。我将包含下面的代码（我已经做了一些努力来通用化，因此它可能无法编译）。请注意，您可以扩展它以包含一些权限概念（在连接表中）。

直接关系属性的代码。它验证当前用户是否是该记录的所有者（路由参数中指定的“id”属性与用户表中当前用户的id匹配）。

[AttributeUsage( AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false )]
public class RoleOrOwnerAuthorizationAttribute : AuthorizationAttribute
{
    private IDataContextFactory ContextFactory { get; set; }

    private string routeParameter = "id";
    /// <summary>
    /// The name of the routing parameter to use to identify the owner of the data (participant id) in question.  Default is "id".
    /// </summary>
    public string RouteParameter
    {
        get { return this.routeParameter; }
        set { this.routeParameter = value; }
    }

    public RoleOrOwnerAuthorizationAttribute()
        : this( null )
    {
    }

    // this is for unit testing support
    public RoleOrOwnerAuthorizationAttribute( IDataContextFactory factory )
    {
        this.ContextFactory = factory ?? DefaultFactory();
    }

    public override void OnAuthorization( AuthorizationContext filterContext )
    {
        if (filterContext == null)
        {
            throw new ArgumentNullException( "filterContext" );
        }

        if (AuthorizeCore( filterContext.HttpContext ))
        {
            SetCachePolicy( filterContext );
        }
        else if (!filterContext.HttpContext.User.Identity.IsAuthenticated)
        {
            // auth failed, redirect to login page
            filterContext.Result = new HttpUnauthorizedResult();
        }
        else if (filterContext.HttpContext.User.IsInRole( "SuperUser" ) || IsOwner( filterContext ))
        {
            SetCachePolicy( filterContext );
        }
        else
        {
            ViewDataDictionary viewData = new ViewDataDictionary();
            viewData.Add( "Message", "You do not have sufficient privileges for this operation." );
            filterContext.Result = new ViewResult { MasterName = this.MasterName, ViewName = this.ViewName, ViewData = viewData };
        }

    }

    private bool IsOwner( AuthorizationContext filterContext )
    {
        using (var dc = this.ContextFactory.GetDataContextWrapper())
        {
            int id = -1;
            if (filterContext.RouteData.Values.ContainsKey( this.RouteParameter ))
            {
                id = Convert.ToInt32( filterContext.RouteData.Values[this.RouteParameter] );
            }

            string userName = filterContext.HttpContext.User.Identity.Name;

            return dc.Table<UserTable>().Where( p => p.UserName == userName && p.ParticipantID == id ).Any();
        }

    }

}

这是关联属性的代码，即路由参数中的id 和用户表中的用户id 在连接表中存在关联。请注意，存在对 VS2008 示例 中的 System.Linq.Dynamic 代码的依赖性。

[AttributeUsage( AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false )]
public class RoleOrOwnerAssociatedAuthorizationAttribute : MasterEventAuthorizationAttribute
{
    private IDataContextFactory ContextFactory { get; set; }

    public RoleOrOwnerAssociatedAuthorizationAttribute()
        : this( null )
    {
    }

    // this supports unit testing
    public RoleOrOwnerAssociatedAuthorizationAttribute( IDataContextFactory factory )
    {
        this.ContextFactory = factory ?? new DefaultDataContextFactory();
    }

    /// <summary>
    /// The table in which to find the current user by name.
    /// </summary>
    public string UserTable { get; set; }
    /// <summary>
    /// The name of the property in the UserTable that holds the user's name to match against
    /// the current context's user name.
    /// </summary>
    public string UserNameProperty { get; set; }
    /// <summary>
    /// The property to select from the UserTable to match against the UserEntityProperty on the JoinTable
    /// to determine membership.
    /// </summary>
    public string UserSelectionProperty { get; set; }
    /// <summary>
    /// The join table that links users and the entity table.  An entry in this table indicates
    /// an association between the user and the entity.
    /// </summary>
    public string JoinTable { get; set; }
    /// <summary>
    /// The property on the JoinTable used to hold the entity's key.
    /// </summary>
    public string EntityProperty { get; set; }
    /// <summary>
    /// The property on the JoinTable used to hold the user's key.
    /// </summary>
    public string UserEntityProperty { get; set; }
    /// <summary>
    /// The name of the route data parameter which holds the group's key being requested.
    /// </summary>
    public string RouteParameter { get; set; }

    public override void OnAuthorization( AuthorizationContext filterContext )
    {
        using (var dc = this.ContextFactory.GetDataContextWrapper())
        {
            if (filterContext == null)
            {
                throw new ArgumentNullException( "filterContext" );
            }

            if (AuthorizeCore( filterContext.HttpContext ))
            {
                SetCachePolicy( filterContext );
            }
            else if (!filterContext.HttpContext.User.Identity.IsAuthenticated)
            {
                // auth failed, redirect to login page
                filterContext.Result = new HttpUnauthorizedResult();
            }
            else if (filterContext.HttpContext.User.IsInRole( "SuperUser" )
                     || IsRelated( filterContext, this.GetTable( dc, this.JoinTable ), this.GetTable( dc, this.UserTable ) ))
            {
                SetCachePolicy( filterContext );
            }
            else
            {
                ViewDataDictionary viewData = new ViewDataDictionary();
                viewData.Add( "Message", "You do not have sufficient privileges for this operation." );
                filterContext.Result = new ViewResult { MasterName = this.MasterName, ViewName = this.ViewName, ViewData = viewData };
            }
        }
    }

    protected bool IsRelated( AuthorizationContext filterContext, IQueryable joinTable, IQueryable userTable )
    {
        bool result = false;
        try
        {
            int entityIdentifier = Convert.ToInt32( filterContext.RouteData.Values[this.RouteParameter] );
            int userIdentifier = this.GetUserIdentifer( filterContext, userTable );

            result = joinTable.Where( this.EntityProperty + "=@0 and " + this.UserEntityProperty + "=@1",
                                      entityIdentifier,
                                      userIdentifier )
                              .Count() > 0;
        }
        catch (NullReferenceException) { }
        catch (ArgumentNullException) { }
        return result;
    }

    private int GetUserIdentifer( AuthorizationContext filterContext, IQueryable userTable )
    {
        string userName = filterContext.HttpContext.User.Identity.Name;

        var query = userTable.Where( this.UserNameProperty + "=@0", userName )
                             .Select( this.UserSelectionProperty );

        int userIdentifer = -1;
        foreach (var value in query)
        {
            userIdentifer = Convert.ToInt32( value );
            break;
        }
        return userIdentifer;
    }

    private IQueryable GetTable( IDataContextWrapper dc, string name )
    {
        IQueryable result = null;
        if (!string.IsNullOrEmpty( name ))
        {
            DataContext context = dc.GetContext<DefaultDataContext>();
            PropertyInfo info = context.GetType().GetProperty( name );
            if (info != null)
            {
                result = info.GetValue( context, null ) as IQueryable;
            }
        }
        return result;
    }
}

Answer 2

我在 类似问题 ="http://groups.google.com/group/sharp-architecture" rel="nofollow noreferrer">S#arp Architecture 新闻组，其中 Tom Cabanski 建议了一个 AOP 框架，例如 PostSharp 。这看起来是满足我需求的可行解决方案，因此我计划更深入地研究它。不幸的是，这并不是您问题的完整答案，因为我没有可以分享的代码示例。