表示深层资源树的最佳方式？

Question

是否有一种简单的方法可以重用路由“段”以及用于验证和使用段中参数的控制器逻辑？

例如，我想像这样表示我的资源：

• 房屋
  • {住宅地址}
    • 架构
      • 屋顶
      • 壁板
    • 房间
      • 生活
        • 门
        • 窗户
      • 餐饮
        • 门
        • 窗户
      • 厨房
        • 门
        • 窗户
      • 卧室
        • [0]
          • 门
          • 窗户
        • [1]
          • 门
          • 窗户

以下是一种可行的方法。 有什么更好的方法？

[Route("[controller]")]
[ApiController]
class HousesController : ControllerBase
{
    [HttpGet]
    public IEnumerable<House> Get() => _housesRepo.GetAll();

    [HttpGet("{houseId}")]
    public ActionResult<House> Get(string houseId)
    {
        if (!_housesRepo.TryGetHouse(houseId, out var house))
            return NotFound("Bad house ID");
    }
}

class RoomsController : ControllerBase
{
    [HttpGet("~houses/{houseId}/rooms/bedrooms/{bedroomId}")]
    public ActionResult<Room> GetBedroom(string houseId, int bedroomId)
    {
        if (!_housesRepo.TryGetHouse(houseId, out var house))
            return NotFound("Bad house ID");
        var bedrooms = house.Bedrooms;
        if (bedroomId < 0 || bedroomId >= bedrooms.Length)
            return NotFound("Bad bedroom ID");
        return bedrooms[bedroomId];
    }

    [HttpGet("~houses/{houseId}/rooms/{roomClass}")]
    public ActionResult<Room> GetRoom(string houseId, string roomClass)
    {
        if (!_housesRepo.TryGetHouse(houseId, out var house))
            return NotFound("Bad house ID");
        var roomsByClass = house.RoomsByClass;
        if (!roomsByClass.TryGetValue(roomClass, out var room))
            return NotFound("Bad room class");
        return room;
    }
}

class ArchitectureController : ControllerBase
{
    [HttpGet("~houses/{houseId}/architecture")]
    public ActionResult<string[]> Get(string houseId)
    {
        if (!_housesRepo.TryGetHouse(houseId, out _))
            return NotFound("Bad house ID");
        return new [] { "roof", "siding" };
    }

    [HttpGet("~houses/{houseId}/architecture/roof")]
    public ActionResult<Roof> GetRoof(string houseId)
    {
        if (!_housesRepo.TryGetHouse(houseId, out var house))
            return NotFound("Bad house ID");
        return house.Architecture.Roof;
    }

    [HttpGet("~houses/{houseId}/architecture/siding")]
    public ActionResult<Siding> GetSiding(string houseId)
    {
        if (!_housesRepo.TryGetHouse(houseId, out var house))
            return NotFound("Bad house ID");
        return house.Architecture.Siding;
    }
}

但请注意有多少重复：

• ~houses/{houseId}路段
• 验证houseId 并检索关联的House

随着资源变得越来越复杂，重复只会变得更糟。

微软似乎在推动人们拥有一个非常扁平的层次结构。例如：

• ~houses/{houseId}
• ~architecture/{architectureId}
• ~rooms/{roomId}

但这只会隐藏问题。例如，Room 仅作为House 的组成部分才有意义，因此{roomId} 还必须包含有关房屋ID 的信息。然后我需要解析roomId 以提取houseId 以验证和提取关联的House 资源。

如果我能有这个就好了：

[Segment("HOUSE")]
[HttpGet("houses/{houseId}")]
public ActionResult<House> GetHouse(string houseId) => _housesRepo
    .TryGetValue(houseId, out var house)
    ? new ActionResult<House>(house)
    : NotFound("Bad house ID");

[HttpGet("[HOUSE]/architecture")]
public string[] GetArchitectureCategories(House house) => new [] { "roof", "siding" };

[HttpGet("[HOUSE]/architecture/roof")]
public Roof GetRoof(House house) => house.Architecture.Roof;

[HttpGet("[HOUSE]/architecture/siding")]
public Siding GetSiding(House house) => house.Architecture.Siding;

[Segment("BEDROOM")]
[HttpGet("[HOUSE]/rooms/bedrooms/{bedroomId}")]
public Room GetBedroom(House house, int bedroomId) => house.Bedrooms[bedroomId];

[Segment("ROOM")]
[HttpGet("[HOUSE]/rooms/{roomClass}")]
public ActionResult<Room> GetRoom(House house, string roomClass) => house
    .RoomsByClass
    .TryGetValue(roomClass, out var room)
    ? new ActionResult<Room>(room)
    : NotFound("Bad room class");

这将很容易建立。例如，我可以快速添加门窗控制器：

[HttpGet("[ROOM|BEDROOM]/doors")]
public Door[] GetDoors(Room room) => room.Doors;

[HttpGet("[ROOM|BEDROOM]/windows")]
public Window[] GetWindows(Room room) => room.Windows;

Answer 1

正如您所说，这是不可能的，但仍然可以实现。首先，您希望依赖应用于控制器类本身的路​​由前缀。换句话说，而不是：

[HttpGet("~houses/{houseId}/rooms/bedrooms/{bedroomId}")]
public ActionResult<Room> GetBedroom(string houseId, int bedroomId)

用途：

[Route("houses/{houseId}/rooms")]
public class RoomsController : ControllerBase
{
    [HttpGet("bedrooms/{bedroomId}")]
    public ActionResult<Room> GetBedroom(int bedroomId)

然后，还要注意我在那里取出了houseId 参数。这个逻辑可以移出到OnActionExecutionAsync的覆盖中：

private House House { get; set; }

public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
    if (context.RouteData.Values.TryGetValue("houseId", out var houseId))
    {
        House = await _context.Set<House>().FindAsync(houseId);
        if (House == null)
            context.Result = NotFound();
    }

    await base.OnActionExecutionAsync(context, next);
}

这看起来有点复杂，但所做的只是从路径中拉出houseId 参数并尝试找到相关联的房子。如果没有找到，则立即返回 404，否则，控制器上的 House 属性将设置为该房屋。因此，您在此控制器中的每个操作现在都可以依赖可用的 House 属性并可以相应地使用它，而只需关注自己的特定行为。