GroupBy后GroupBy

Question

我有以下DTO：

class Permission
{
    public string ObjectId { get; set; }
    public string ObjectType { get; set; }
    public string Scope { get; set; }
    public string? AccountId { get; set; }
    public string? GroupId { get; set; }
}

var permissions = new List<Permission>()
{
    new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = "1", GroupId = null },
    new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = "2", GroupId = null },
    new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = null, GroupId = "1" },
    new(){ ObjectId = "1", ObjectType = "link", Scope = "link:write", AccountId = "2", GroupId = null },
    new(){ ObjectId = "2", ObjectType = "link", Scope = "link:read", AccountId = "1", GroupId = null },
};

我希望得到以下结果：

{[
    "1": {
        "read": {
            "accounts": ["1", "2"],
            "groups": ["1", "2", "3"]
        },
        "write": {
            "accounts": ["1", "2"],
            "groups": ["1", "2", "3"]
        }
  }
]}

基本上是Permission的一个对象数组，按其ObjectId属性分组，然后按每个包含AccountId或GroupId属性数组的Scope进行分组。

每个Permission可以有相同的ObjectId，但是有不同的Scope、AccountId和GroupId。

我尝试使用GroupBy，但这给了我一个IGrouping，我不知道如何继续。

Answer 1

您需要的不仅仅是嵌套的组bys。在您的输出JSON中，您有键作为属性名。您还需要使用ToDictionary将值转换为属性键。

var permissions = new List<Permission>()
        {
            new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = "1", GroupId = null },
            new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = "2", GroupId = null },
            new(){ ObjectId = "1", ObjectType = "link", Scope = "link:read", AccountId = null, GroupId = "1" },
            new(){ ObjectId = "1", ObjectType = "link", Scope = "link:write", AccountId = "2", GroupId = null },
            new(){ ObjectId = "2", ObjectType = "link", Scope = "link:read", AccountId = "1", GroupId = null },
        };
        var result = permissions.GroupBy(r=> r.ObjectId).Select(r=> new {
            r.Key,
            InnerGroups = r.GroupBy(q=> q.Scope.Replace("link:","")).Select(q=> new {
                Scope = q.Key,
                Accounts =  q.Where(z=> z.AccountId != null).Select(z=> z.AccountId).ToArray(),
                Groups = q.Where(z=> z.GroupId != null).Select(z=> z.GroupId).ToArray()
            })
        })
            .ToDictionary(r=> r.Key,r=> r.InnerGroups.ToDictionary(q=> q.Scope,q=> new {q.Accounts,q.Groups}));
        
        var serialized = JsonSerializer.Serialize(result,new JsonSerializerOptions{ WriteIndented=true });

这是输出：

 {
  "1": {
    "read": {
      "Accounts": [
        "1",
        "2"
      ],
      "Groups": [
        "1"
      ]
    },
    "write": {
      "Accounts": [
        "2"
      ],
      "Groups": []
    }
  },
  "2": {
    "read": {
      "Accounts": [
        "1"
      ],
      "Groups": []
    }
  }
}

小提琴

Answer 2

您必须使用嵌套的GroupBy来实现这一点，然后将结果转换为字典：

var result = permissions
    .GroupBy(p => p.ObjectId)
    .ToDictionary(g => g.Key, g => g.GroupBy(g => g.Scope)
    .ToDictionary(g => g.Key, g => new
    {
        accounts = g.Select(per => per.AccountId).Distinct().ToList(),
        groups = g.Select(per => per.GroupId).Distinct().ToList()
    }));