如何从 Vapor 中的数组制作 "future"?

How to make "future" from an array in Vapor?

有以下代码:

router.get("/fetchOngoingReleases", String.parameter) { (request) -> Future<[ReleaseWithUser]> in
    return Release.query(on: request).filter(\.inProgress == true).all().flatMap { (ra) -> EventLoopFuture<[ReleaseWithUser]> in
        let userId = try request.parameters.next(String.self)
        return User.query(on: request).filter(\.fbId == userId).first().flatMap { (user) -> EventLoopFuture<[ReleaseWithUser]> in
            let a = ra.map { (r) -> ReleaseWithUser in
                // some condition and logic here
            }

            return a. //need this to make future
        }
    }
}

我检查了所有可能的方法调用,但 none of 将 [ReleaseWithUser] 转换为 Future<[ReleaseWithUser]>。你有什么想法吗?

解决方案是:

ra.map { (r) -> ReleaseWithUser in
// some condition and logic here
}.flatten(on: request)

数组可以通过flatten()转换为未来的数组。