嵌套的Alamofire请求

Question

I am making a nested Alamofire requests and populating my class property objects with the returned data. The first Alamofire request works and I am able to inject data to my class object in the first Alamofire request, but the second request, although I see data returned from my API, I am unable to append the data to my class property which is an array if cities.

 // Get States
getStatesByUserID(userID) {
    (result)->() in
    var states = JSON(result)
    for index in 0... states.count - 1 {
        let statesID: Int = states[index]["stateID"].intValue
        let statesName: String = states[index]["title"].stringValue


        // Get Cities by State ID
        self.getCities(stateID) {
            (result) -> () in
            let cities = JSON(result)
            for index in 0...cities.count - 1 {
                let cityID: Int = cities[index]["cityID"].intValue
                let cityName: String = cities[index]["title"].stringValue

                //Append a single city into cities array
                self.city.append(City(id: cityID, name: cityName))
            }
        }

        // Append a single state that contains cities and zips into states array
        self.state.append(State(id: stateID, name: stateName, city:self.city ))
    }
}
self.tableView.reloadData()
}

Answer 1

Alamofire works asynchronously, if your second request depends of the first one and your trying to append your data in the same callback probably your asking for data that hasn't been retrieved yet. if this is the case you could await until the first request finish his job for example:

   public func SendPicAndSig(ip: String, enerImg: EnerImage, callBack:((JSONData:JSON)->Void)?){
    let address:String = "http://\(ip)/Enercard.Service/api/UploadFiles"

    let serial =  JSONSerializer.toJson(enerImg)
    let _parametros = JSONSerializer.toDictionary(serial) as! [String : AnyObject]

    debugPrint(_parametros)
    Alamofire.request(.POST,address, parameters: _parametros, encoding:.JSON)
        .responseJSON { _,_,result in
            switch result
            {
            case .Success(let data):
                //posible handling de error de parte del servidor
                debugPrint(result.data)
                  callBack?(JSONData: JSON(data))
            default:()
                break
            }
    }
}

here i have an example function that I use to send and object and I have CallBack used as a parameters, this callback method will run only when the data is successfully retrieved so I could later call this function as

SendPicAndSif("10.11.1.217" , Image("random-path"),SecondRequest)

where "SecondRequest" is going to be the function that i will run if I retrieve the data of the first request so

SecondRequest(jsonarray:JSON)
{
  //second  Alamofire request
}