Data Handling in Swift

Question

I have a custom class whose values are taken from the following data Structure

{
  key1 = value1 ;
  key2 = value2;
  ...}

I can handle this data structure . With another request, i have the following data structure :

{
 rootKey = {
   key1 = value1;
   key2 = value2;
   ..};`enter code here`
 }

i would like to parse it or use another method to get the result as in the first structure. Having a java background and little swift experience, i couldn t find a easy and fast way to do it.

You need more detail in the question. Is this coming from JSON? Do you have actual class or struct definitions for either type made? — jnpdx, Mar 15 '21 at 17:36
this is coming from datasnapshot in firebase . The first struct allows me to use a decoder to retrieve an instance of a custom class . From firebase requests , i couldn t have a precise answser just too loop again and again to have the mandatory values Since the elements to be removed always have the same strcuture , i would prefer just removing the unecessary data in order to have a clean solution instead of loops — it75, Mar 15 '21 at 17:58
https://stackoverflow.com/questions/66630825/request-result-structure-firebasedatabase-swift — it75, Mar 15 '21 at 18:02

score 0 · Answer 1 · answered Mar 15 '21 at 19:21

If you use Decodable structs, you must define 2 data structures:

struct First: Decodable {
    let key1: String
    let key2: String
}

struct Second: Decodable {
    let rootKey: First
}

Then you can perform two different data requests, obtain different json Data objects. For the first case you try to decode First object:

func request1(completion: (Result<First, Error>) -> Void) {
    // make async request for data
    let data = Data()

    // decode result and call your completion handler in request completion
    do {
        let model = try JSONDecoder().decode(First.self, from: data)
        completion(.success(model))
    } catch {
        completion(.failure(error))
    }
}

For the second one, you try to decode the Second object, but take only the First object from rootKey:

func request2(completion: (Result<First, Error>) -> Void) {
    // make async request for data
    let data = Data()

    // decode result and call your completion handler in request completion
    do {
        let model = try JSONDecoder().decode(Second.self, from: data)
        // take the First object from decoded result
        completion(.success(model.rootKey))
    } catch {
        completion(.failure(error))
    }
}

Hello, thank you . I m not sure i got it right for the second decodable . I need the first one only. In the description i made , i attached the link to the same problem but from a firebase point of view . I use firebase decode which is i guess the same kind of Json decoder . using firebase decoder or json decoder on the provided data, i get an error. Without the rootkey part, it works fine, i just don t know how to get rid of the rootkey from the data.Having several requests from a query that only takes one request in java is what i want to avoid — it75, Mar 15 '21 at 20:06

Data Handling in Swift

1 Answers1