如何查询更多记录并使用Vapor进行处理？

Question

路由器在 JSON 中收到更多 ID。需要为每个 Id 执行一个查询。然后对原始数据和 return 进行一些操作。但是我得到了一些错误。以及如何管理Futures？每个查询都会return一个独特的未来？我需要检查所有 Futures 何时完成？我是否需要使用 DispathGroup，或者如何使用？

我是这样制作的：

router.post([Page].self, at: "/releases") { (request, pages) -> [Page] in
    for page in pages {
        for event in page.events {
            let release = Release.query(on: request).filter(\.fbId == event.id).first().flatMap { (release) -> EventLoopFuture<Release?> in
                return request.future(release)
            }
            if let release2 = release {
                event.started = release2.started
            }
        }
    }
    return pages
}

但它引发了一些错误：

使用了以下 JSON：

[
    {
        "id": "107120697426006",
        "name": "Teszt Színház",
        "events": [
            {
                "id": "802128100247740",
                "name": "Teszt Esemény"
            },
            {
                "id": "1378145475685730",
                "name": "Teszt Esemény 2"
            }
        ]
    }
]

Answer 1

类似的东西应该可以工作

router.post([Page].self, at: "/releases") { (req, pages) -> Future<[Page]> in
    var result: [Page] = []
    return pages.map { p in
        var page = p
        var pageEvents: [Event] = []
        return page.events.map { e in
            var event = e
            return Release.query(on: req).filter(\.fbId == event.id).first().map { release in
                if let release = release {
                    event.started = release.started
                }
                pageEvents.append(event)
            }
        }.flatten(on: req).map {
            page.events = pageEvents
            result.append(page)
        }
    }.flatten(on: req).transform(to: result)
}

或者调用一次数据库会更好

import FluentSQL // for `~~` operator

router.post([Page].self, at: "/releases") { (req, pages) -> Future<[Page]> in
    let eventIds = pages.map { [=11=].events }.flatMap { [=11=] }.map { [=11=].id }
    return Release.query(on: req).filter(\.fbId ~~ eventIds).all().map { releases in
        var result: [Page] = []
        for p in pages {
            var page = p
            var pageEvents: [Event] = []
            for e in p.events {
                var event = e
                if let release = releases.first(where: { [=11=].fbId == e.id }) {
                    event.started = release.started
                }
                pageEvents.append(event)
            }
            page.events = pageEvents
            result.append(page)
        }
        return result
    }
}

如何查询更多记录并使用Vapor进行处理？

How to query more records and process them with Vapor?

grand-central-dispatch

vapor