如何使用 child 保存模型并使用 child 返回保存的模型作为 Vapor 3 中的响应

Question

我正在尝试编写一个控制器函数来同时插入一个带有 child 模型的模型，并在 return 中获得相同的 JSON 响应，但填充了从数据库添加的数据（即自动生成的id）。

对于下面的简化示例，JSON 请求正文如下所示：

{
    "field1": "blabla",
    "subContent": {
        "field2": "lalala"
    }
}

我期待以下回复：

{
    "id": 5,
    "field1": "blabla",
    "subContent": {
        "id": 44,
        "field2": "lalala"
    }
}

不幸的是，下面的代码无法编译，错误消息显示“无法将类型 'EventLoopFuture' 的表达式转换为 return 类型 'Response'。这发生在行

return subModel.create(on: req).flatMap { savedSubModel ->

代码如下：

struct MainContent: Content {
    var id: UUID?
    var field1: String
    var subContent: SubContent
}

struct SubContent: Content {
    var id: UUID?
    var field2: String
}

final class Controller {
    func create(_ req: Request) throws -> EventLoopFuture<Response> {
        return try req.content.decode(MainContent.self).map { request in
            let subModel = SubModel(
                field2: request.subContent.field2
            )
            return subModel.create(on: req).flatMap { savedSubModel -> EventLoopFuture<Response> in
                let mainModel = mainModel(
                    subModelId: savedSubModel.id!,
                    field1: request.field1
                )
                return mainModel.create(on: req).flatMap { savedMainModel -> EventLoopFuture<Response> in
                    let content = MainContent(
                        id: savedMainModel.id,
                        field1: savedMainModel.field1,
                        subContent: SubContent(
                            id: savedSubContent.id,
                            field2: savedSubContent.field2
                        )
                    )
                    return content.encode(status: .created, for: req)
                }
            }
        }
    }
}

Answer 1

struct MainContent: Content {
    var id: UUID?
    var field1: String
    var subContent: SubContent
}

struct SubContent: Content {
    var id: UUID?
    var field2: String
}

final class Controller {
    func create(_ req: Request) throws -> EventLoopFuture<Response> {
        return try req.content.decode(MainContent.self).flatMap { request in
            let subModel = SubModel(
                field2: payload.subContent.field2
            )
            return subModel.create(on: req)
        }.flatMap { savedSubModel in
            let mainModel = mainModel(
                subModelId: try savedSubModel.requireID(),
                field1: request.field1
            )
            return mainModel.create(on: req).flatMap { savedMainModel in
                let content = MainContent(
                    id: try savedMainModel.requireID(),
                    field1: savedMainModel.field1,
                    subContent: SubContent(
                        id: try savedSubModel.requireID(),
                        field2: savedSubModel.field2
                    )
                )
                return content.encode(status: .created, for: req)
            }
        }
    }
}

如何使用 child 保存模型并使用 child 返回保存的模型作为 Vapor 3 中的响应

How to save a model with a child and get the saved model with child back as a response in Vapor 3

swift

vapor