Parsing verschachtelte Array mit codable in Swift 4

Question

Ich bekomme viele zufällige Probleme. Meistens ist eine Struktur nicht decodierbar und nicht in der Lage zu verstehen, wie man eine Struktur definiert.

finden Sie den Code snipped

var JSON = """ 
{"variants":{"variant_groups":[{"group_id":"1","name":"Crust","variations":[{"name":"Thin","price":0,"default":1,"id":"1","inStock":1},{"name":"Thick","price":0,"default":0,"id":"2","inStock":1,"isVeg":1},{"name":"Cheese burst","price":100,"default":0,"id":"3","inStock":1,"isVeg":1}]},{"group_id":"2","name":"Size","variations":[{"name":"Small","price":0,"default":1,"id":"10","inStock":1,"isVeg":0},{"name":"Medium","price":100,"default":0,"id":"11","inStock":1,"isVeg":1},{"name":":Large","price":200,"default":0,"id":"12","inStock":1,"isVeg":0}]},{"group_id":"3","name":"Sauce","variations":[{"name":"Manchurian","price":20,"default":0,"id":"20","inStock":1,"isVeg":0},{"name":"Tomato","price":20,"default":0,"id":"21","inStock":1,"isVeg":1},{"name":"Mustard","price":20,"default":0,"id":"22","inStock":1,"isVeg":0}]}],"exclude_list":[[{"group_id":"1","variation_id":"3"},{"group_id":"2","variation_id":"10"}],[{"group_id":"2","variation_id":"10"},{"group_id":"3","variation_id":"22"}]]}} 
""".data(using: .utf8) 

/* 
not sure is this the right way to define Root 
*/ 
    struct Root : Codable { 

     let variants : varientStruct 
     let exclude_list : exclude_list 

    } 

    struct exclude_list : Codable{ 
     let variation_id : String 
     let group_id : String 
    } 

    struct varientStruct: Codable { 
     let variant_groups = [variant_groups_struct] 
    } 
    struct variant_groups_struct : Codable { 
     let group_id : String 
     let name :String 
     let variations: [variationsStruct] 
    } 

    struct variationsStruct :Codable { 
     let name : String 
     let price : Int 
     let selected: Int 
     let id : String 
     let inStock: Bool 

     enum CodingKeys : String, CodingKey { 
      case name 
      case price 
      case selected = "default" 
      case id 
      case inStock 
     } 
    } 
} 

do { 
    let data = Data(person.utf8) 
    let result = try JSONDecoder().decode(Root.self, from: JSON) 
    print(result) 
} catch { 
    print(error) 
} 

Answer 1

Zunächst einmal und noch einmal, entsprechen Sie in der Namenskonvention:

• struct und class Namen beginnen mit einem Groß Brief.
• Variablen- und Funktionsnamen beginnen mit einem Kleinbuchstaben Buchstaben.
• Alle Variable und struct/class Namen sind camelcased statt snake_cased.

Zweitens ist JSON sehr einfach zu lesen. Es gibt nur zwei Auflistungstypen (Array [] und Verzeichnis {}) und vier Werttypen.

Format der JSON-String der Lage sein, die Struktur bequemer die Strukturen bauen

let jsonString = """ 
{"variants":{"variant_groups":[{"group_id":"1","name":"Crust","variations": 
            [{"name":"Thin","price":0,"default":1,"id":"1","inStock":1}, 
            {"name":"Thick","price":0,"default":0,"id":"2","inStock":1,"isVeg":1}, 
            {"name":"Cheese burst","price":100,"default":0,"id":"3","inStock":1,"isVeg":1}] 
           },{"group_id":"2","name":"Size","variations": 
            [{"name":"Small","price":0,"default":1,"id":"10","inStock":1,"isVeg":0}, 
            {"name":"Medium","price":100,"default":0,"id":"11","inStock":1,"isVeg":1}, 
            {"name":":Large","price":200,"default":0,"id":"12","inStock":1,"isVeg":0}] 
           },{"group_id":"3","name":"Sauce","variations": 
            [{"name":"Manchurian","price":20,"default":0,"id":"20","inStock":1,"isVeg":0}, 
            {"name":"Tomato","price":20,"default":0,"id":"21","inStock":1,"isVeg":1}, 
            {"name":"Mustard","price":20,"default":0,"id":"22","inStock":1,"isVeg":0}] 
           }], 
      "exclude_list":[[{"group_id":"1","variation_id":"3"}, {"group_id":"2","variation_id":"10"}], 
          [{"group_id":"2","variation_id":"10"},{"group_id":"3","variation_id":"22"}]] 
      } 
} 
""" 

dann zu erkennen, entsprechend dem JSON Struktur Schritt für Schritt

struct Root : Decodable { 
    let variants : Variant 
} 

struct Variant : Decodable { 

    private enum CodingKeys : String, CodingKey { 
     case groups = "variant_groups" 
     case excludeList = "exclude_list" 
    } 

    let groups : [VariantGroup] 
    let excludeList : [[ExcludeList]] 
} 

struct VariantGroup : Decodable { 

    private enum CodingKeys : String, CodingKey { 
     case groupID = "group_id" 
     case name, variations 
    } 

    let groupID : String 
    let name : String 
    let variations : [Variation] 
} 

struct Variation : Decodable { 

    let name : String 
    let price : Int 
    let `default` : Int 
    let id : String 
    let inStock : Int 
} 


struct ExcludeList : Decodable { 
    private enum CodingKeys : String, CodingKey { 
     case groupID = "group_id" 
     case variationID = "variation_id" 
    } 

    let groupID : String 
    let variationID : String 
} 

das Zeug dann dekodieren

do { 
    let data = Data(jsonString.utf8)  
    let result = try JSONDecoder().decode(Root.self, from: data) 
    print(result) 

} catch { print(error) }