asp.net-mvc-3 - "user may do X is user owns object Y": Implement logic in Model Validation or Controller logic?

Question

例如，考虑逻辑“用户只能编辑或删除该用户发表的评论”。

My Controller Actions会重复检查当前登录用户是否可以影响评论的逻辑。示例

[Authorize]
public ActionResult DeleteComment(int comment_id)
{
    var comment = CommentsRepository.getCommentById(comment_id);
    if(comment == null) 
        // Cannot find comment, return bad input
        return new HttpStatusCodeResult(400); 
    if(comment.author != User.Identity.Name)
        // User not allowed to delete this comment, return Forbidden
        return new HttpStatusCodeResult(403);
    // Error checking passed, continue with delete action
    return new HttpStatusCodeResult(200);
}

当然，我可以将该逻辑捆绑在一个方法中，这样我就不会复制/粘贴该片段；但是，将该代码从 Controller 中取出并将其放入 ValidationAttribute 中可以使我的 Action 更小并且更容易为其编写测试。示例

public class MustBeCommentAuthorAttribute : ValidationAttribute
{
    // Import attribute for Dependency Injection
    [Import]
    ICommentRepository CommentRepository { get; set; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        int comment_id = (int)value;
        var comment = CommentsRepository.getCommentById(comment_id);
        if(comment == null) 
            return new ValidationResult("No comment with that ID"); 
        if(comment.author != HttpContext.Current.User.Identity.Name)
            return new ValidationResult("Cannot edit this comment");
        // No errors
        return ValidationResult.Success;
     }
}

public class DeleteCommentModel
{
    [MustBeCommentAuthor]
    public int comment_id { get; set; }
}

模型验证是否适合这项工作？我喜欢从 Controller Action 中消除这种担忧；但在这种情况下，它可能会使事情进一步复杂化。当您认为此操作是 RESTful API 的一部分并且需要根据 ModelState 中的验证错误返回不同的 HTTP 状态代码时，尤其如此。

在这种情况下是否有“最佳实践”？

Answer 1

就我个人而言，我认为它看起来不错，但您会被注释冲昏头脑。我认为这不属于您的表示层，应该由您的服务层处理。

我想说的是:

[Authorize] 
public ActionResult DeleteComment(int comment_id) 
{ 
    try
    {
       var result = CommentsService.GetComment(comment_id, Auth.Username);

       // Show success to the user
    }
    catch(Exception e)
    {
       // Handle by displaying relevant message to the user
    }
}