JSON Parsing Decodable in Swift 4 - json

Question

With the json below, is it possible to get those keys under "fields" and print out one by one using for loop. (path, public_key, icon, name, description)
{
"fields" : {
"path" : { "type" : "text", "source" : "path" },
"public_key" : { "type" : "text", "source" : "public_key" },
"icon" : { "type" : "image", "source" : "icon" },
"name" : { "type" : "text", "source" : "name" },
"description" : { "type" : "text", "source" : "description" }
},
"parName" : "myapps",
"method" : 103,
"table" : "appslist",
"callBackID" : "25b4599a-eead-6f6c-894e-e4de05b1364b"
}
My object model
struct params: Decodable {
let fields: fields?
let parName: String?
let method: Int?
let table: String?
let callBackID: String?
}
struct fields: Decodable {
let name: properties?
let description: properties?
let public_key: properties?
let path: properties?
let icon: properties?
let imagelist: properties?
let templatepath: properties?
let thumbnail: properties?
}
struct properties: Decodable {
let source: String?
let type: String?
}

Answer 1

If you want a loop and the keys are dynamic decode the fields as [String:Properties]
First of all declare the structs with capitalized names and declare only those properties as optional which can be nil.
struct Params: Decodable {
let fields: [String:Properties]
let parName: String
let method: Int
let table: String
let callBackID: String
}
struct Properties: Decodable {
let source: String
let type: String
}
Then decode the JSON, define an array of key paths and enumerate the array (data is the Data instance representing the JSON)
do {
let result = try JSONDecoder().decode(Params.self, from: data)
let fields = result.fields
for (key, _) in result.fields {
print(key)
}
} catch {
print("error: ", error)
}