[英]How to flatten multiple queries in Vapor
我需要對不同的表進行大量查詢,並在一個響應中返回結果。 我想知道我可以展平極其嵌套的函數嗎?
final class CodeController {
internal func indexCodes(_ req: Request) throws -> EventLoopFuture<Response> {
CodeCountry.query(on: req).sort(\.name).all().flatMap { countries -> EventLoopFuture<Response> in
CodeFloor.query(on: req).sort(\.name).all().flatMap { floors -> EventLoopFuture<Response> in
CodeRegion.query(on: req).sort(\.name).all().flatMap { regions -> EventLoopFuture<Response> in
CodeObjectType.query(on: req).sort(\.name).all().flatMap { objectTypes -> EventLoopFuture<Response> in
CodePropertyType.query(on: req).sort(\.name).all().flatMap { propertyTypes -> EventLoopFuture<Response> in
CodeRooms.query(on: req).sort(\.name).all().flatMap { rooms -> EventLoopFuture<Response> in
let codes = CodesContent(
countries: countries,
floors: floors,
regions: regions,
objectTypes: objectTypes,
propertyTypes: propertyTypes,
rooms: rooms
)
return codes.encode(status: .ok, for: req)
}
}
}
}
}
}
}
}
這可能不是最好看的代碼,但我認為解決了這個問題。 我喜歡@Nick 將新數據模型作為集合引入的方法,所以也會做類似的事情。 您可以合並兩個期貨並獲得一個。 這來自 SwiftNIO
let futureThingOne: Future<ThingOne> = ...
let futureThingTwo: Future<ThingTwo> = ...
let futureBothThings: Future<(ThingOne, ThingTwo)> = futureThingOne.and(futureThingTwo)
因此,通過合並來自查詢的期貨,您可以構建一個扁平化的結構。
struct Codes: Content {
let countries: [CodeCountry]
let floors: [CodeFloor]
let regions: [CodeRegion]
let objectTypes: [CodeObjectType]
let propertyTypes: [CodePropertyType]
let rooms: [CodeRooms]
static func codes(req: Request) -> Future<Codes> {
let futureCountries = CodeCountry.query(on: req).sort(\.name).all()
let futureFloors = CodeFloor.query(on: req).sort(\.name).all()
let futureRegions = CodeRegion.query(on: req).sort(\.name).all()
let futureObjectTypes = CodeObjectType.query(on: req).sort(\.name).all()
let futurePropertyTypes = CodePropertyType.query(on: req).sort(\.name).all()
let futureRooms = CodeRooms.query(on: req).sort(\.name).all()
let combined = futureCountries.and(futureFloors).and(futureRegions).and(futureObjectTypes).and(futurePropertyTypes).and(futureRooms)
return combined.map {
Codes.init(
countries: $0.0.0.0.0.0,
floors: $0.0.0.0.0.1,
regions: $0.0.0.0.1,
objectTypes: $0.0.0.1,
propertyTypes: $0.0.1,
rooms: $0.1
)
}
}
}
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