Aggregation-App-1.swift

struct RGB: Decodable {
    var red: Int
    var green: Int
    var blue: Int
}

struct Colour: Decodable {
    var id: String
    var name: String
    var hex: String
    var rgb: RGB
}

struct Item: Decodable {
    var id: String
    var name: String
}

struct ColourWithItems {
    var colour: Colour
    var items: [Item]
}

private func loadColours() {
    struct ColourDto: Decodable {
        var colours: [Colour]
    }
    struct ItemDto: Decodable {
        var items: [Item]
    }

    let myColoursUrl = URL(string: "http://localhost:8081/my-colours")!
    var request = URLRequest(url: myColoursUrl)
    request.setValue("application/json", forHTTPHeaderField: "Accept")

    URLSession.shared.dataTask(with: request) { [weak self] (data, response, error) in
        guard error == nil else {
            print("Error getting colours")
            return
        }
        guard let content = data else {
            print("Couldn't get any colours")
            return
        }

        do {
            let colourData = try JSONDecoder().decode(ColourDto.self, from: content)
            for colour in colourData.colours {
                let itemsUrl = URL(string: "http://localhost:8082/items/\(colour.id)")!
                URLSession.shared.dataTask(with: itemsUrl) { [weak self] (data, response, error) in
                    guard error == nil else {
                        print("Error getting items for \(colour.id)")
                        return
                    }
                    guard let content = data else {
                        print("Couldn't get any items for \(colour.id)")
                        return
                    }

                    do {
                        let itemData = try JSONDecoder().decode(ItemDto.self, from: content)
                        self?.colours.append(ColourWithItems(colour: colour, items: itemData.items))

                        DispatchQueue.main.async {
                            self?.tableView?.reloadData()
                        }
                    } catch let err {
                        print("Error decoding item json", err)
                    }
                }.resume()
            }

        } catch let err {
            print("Error decoding colour json", err)
        }
    }.resume()
}