Swift closure with Alamofire

Question

I am making API calls to a server. I am leveraging Alamofire to handle this. I\'m trying to create a function that uses Alamofire\'s GET function to return an object based

Answer 1

The code between the {} is the equivalent of block in objective-C : this is a chunk of code that gets executed asynchronously.

The error you made is where you put your return statement : when you launch your request, the code in {} is not executed until the framework received a response, so when the return statement is reached, chances are, there is still no response. You could simply move the line :

return responsePackage

inside the closure, so the func return only when it has received a response. This is a simple way, but it's not really optimal : your code will get stuck at waiting for the answers. The best way you can do this is by using closure, too. This would look something like :

   func get(apiEndPoint: NSString, completion: (response: ResponsePackage) -> ()) -> Bool {

        let responsePackage = ResponsePackage()
        Alamofire
            .request(.GET, apiEndPoint)
            .responseJSON {(request, response, JSON, error) in
                responsePackage.response = JSON
                responsePackage.success = true
                responsePackage.error = error

                completion(response: responsePackage)
        }
    }

Answer 2

I make an example follow your question about responseJSON with closures:

Follow this little steps:

First of all you can create your custom types in a general class (for example a Constants.swift class):

typealias apiSuccess = (result: NSDictionary?) -> Void
typealias apiProgress = (result: NSDictionary?) -> Void // when you want to download or upload using Alamofire..
typealias apiFailure = (error: NSDictionary?) -> Void

Then in your class:

// Normal http request with JSON response..
func callJSONrequest(url:String, params:[String: AnyObject]?, success successBlock :apiSuccess,
    failure failureBlock :apiFailure) {

        Alamofire.request(.GET, url, parameters: params, encoding: ParameterEncoding.URL)
            .responseJSON { response in
                print("\(response.request?.URL)")  // original URL request
                //print(response.response) // URL response
                //print(response.data)     // server data
                //print(response.result)   // result of response serialization
                if response.result.isSuccess {
                    let jsonDic = response.result.value as! NSDictionary
                    successBlock(result: jsonDic)

                } else {
                    let httpError: NSError = response.result.error!
                    let statusCode = httpError.code
                    let error:NSDictionary = ["error" : httpError,"statusCode" : statusCode]
                        failureBlock(error: error)
                    }
                }
        }
}

func myCommonFunction() {
   let myApiSuccess: apiSuccess = {(result: NSDictionary?) -> Void in 
      print ("Api Success : result is:\n \(result)")
      // Here you can make whatever you want with result dictionary
   }
   let myApiFailure: apiFailure = {(error: NSDictionary?) -> Void in 
      print ("Api Failure : error is:\n \(error)")
      // Here you can check the errors with error dictionary looking for http error type or http status code
   }
   var params :[String: AnyObject]?
   let name : String! = "this is my name"
   let id : String! = "000a"
   params = ["name" : name, "id" : id]
   let url : String! = "https://etc..."
   callJSONrequest(url, params:params, success: myApiSuccess, failure: myApiFailure)
}