Swift custom decoding including another custom decoded model - ios

Question

I am currently building a food app using Yelp Fusion API. There are two models called Business and BusinessDatail in my project. To list up restaurants in a tableView, I fetch a restaurant list from backend and custom decode it as an array of Business, [Business]. And then, when a tableViewCell of Business is clicked, I fetch detailed business info and custom decode it as a BusinessDetail.
struct Business {
let id: String
let name: String
let rating: Float?
let price: String?
let displayPhone: String?
let imageUrl: URL
let category: String
let reviewCount: Int
let coordinates: Coordinates
let address: Address
}
struct BusinessDetail {
let id: String
let name: String
let rating: Float?
let price: String?
let displayPhone: String?
let imageUrl: URL
let category: String
let reviewCount: Int
let coordinates: Coordinates
let address: Address
let isClaimed: Bool
let isClosed: Bool
let url: URL
let phone: String?
let photoURLs: [URL]
var hours: [Hours]?
}
Both Business and BusinessDetail are custom decoded models and they are currently initialised this way.
extension Business: Decodable {
enum CodingKeys: String, CodingKey {
case id
case name
case rating
case price
case displayPhone = "display_phone"
case imageUrl = "image_url"
case category = "categories"
case reviewCount = "review_count"
case coordinates
case address = "location"
enum CategoryCodingKeys: String, CodingKey {
case title
}
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
id = try container.decode(String.self, forKey: .id)
name = try container.decode(String.self, forKey: .name)
rating = try container.decode(Float.self, forKey: .rating)
price = try container.decodeIfPresent(String.self, forKey: .price)
displayPhone = try container.decodeIfPresent(String.self, forKey: .displayPhone)
imageUrl = try container.decode(URL.self, forKey: .imageUrl)
var categoriesContainer = try container.nestedUnkeyedContainer(forKey: .category)
var tempCategory = ""
while !categoriesContainer.isAtEnd {
let categoryContainer = try categoriesContainer.nestedContainer(keyedBy: CodingKeys.CategoryCodingKeys.self)
let title = try categoryContainer.decode(String.self, forKey: .title)
tempCategory += tempCategory == "" ? title: ", \(title)"
}
category = tempCategory
reviewCount = try container.decode(Int.self, forKey: .reviewCount)
coordinates = try container.decode(Coordinates.self, forKey: .coordinates)
address = try container.decode(Address.self, forKey: .address)
}
}
extension PlaceDetail: Decodable {
enum CodingKeys: String, CodingKey {
case id
case name
case rating
case price
case displayPhone = "display_phone"
case imageUrl = "image_url"
case category = "categories"
case reviewCount = "review_count"
case coordinates
case address = "location"
enum CategoryCodingKeys: String, CodingKey {
case title
}
case isClaimed = "is_claimed"
case isClosed = "is_closed"
case url
case phone
case photoURLs = "photos"
case hours
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
id = try container.decode(String.self, forKey: .id)
name = try container.decode(String.self, forKey: .name)
rating = try container.decode(Float.self, forKey: .rating)
price = try container.decodeIfPresent(String.self, forKey: .price)
displayPhone = try container.decode(String.self, forKey: .displayPhone)
imageUrl = try container.decode(URL.self, forKey: .imageUrl)
var categoriesContainer = try container.nestedUnkeyedContainer(forKey: .category)
var tempCategory = ""
while !categoriesContainer.isAtEnd {
let categoryContainer = try categoriesContainer.nestedContainer(keyedBy: CodingKeys.CategoryCodingKeys.self)
let title = try categoryContainer.decode(String.self, forKey: .title)
tempCategory += tempCategory == "" ? title: ", \(title)"
}
category = tempCategory
reviewCount = try container.decode(Int.self, forKey: .reviewCount)
coordinates = try container.decode(Coordinates.self, forKey: .coordinates)
address = try container.decode(Address.self, forKey: .address)
isClaimed = try container.decode(Bool.self, forKey: .isClaimed)
isClosed = try container.decode(Bool.self, forKey: .isClosed)
url = try container.decode(URL.self, forKey: .url)
phone = try container.decode(String.self, forKey: .phone)
photoURLs = try container.decode([URL].self, forKey: .photoURLs)
hours = try container.decodeIfPresent([Hours].self, forKey: .hours)
}
}
Here is the json for a business list.
{
"businesses": [
{
"id": "I1D8NHvMWf8oMYceTyLlHg",
"name": "John Mills Himself",
"image_url": "https://s3-media3.fl.yelpcdn.com/bphoto/OH84e6eP8zpzBECF0WvTXA/o.jpg",
"is_closed": false,
"url": "https://www.yelp.com/biz/john-mills-himself-brisbane?adjust_creative=0mCaOEYvfM9_oOaXgMuW6A&utm_campaign=yelp_api_v3&utm_medium=api_v3_business_search&utm_source=0mCaOEYvfM9_oOaXgMuW6A",
"review_count": 55,
"categories": [
{
"alias": "coffee",
"title": "Coffee & Tea"
},
{
"alias": "bakeries",
"title": "Bakeries"
},
{
"alias": "wine_bars",
"title": "Wine Bars"
}
],
"rating": 4.5,
"coordinates": {
"latitude": -27.47151,
"longitude": 153.025654
},
"transactions": [],
"price": "$",
"location": {
"address1": "40 Charlotte St",
"address2": "",
"address3": "",
"city": "Brisbane",
"zip_code": "4000",
"country": "AU",
"state": "QLD",
"display_address": [
"40 Charlotte St",
"Brisbane Queensland 4000",
"Australia"
]
},
"phone": "",
"display_phone": "",
"distance": 383.2254392716822
},
{
"id": "KaIoCOg-IZJtLdN39Cw__Q",
"alias": "strauss-brisbane",
"name": "Strauss",
"image_url": "https://s3-media2.fl.yelpcdn.com/bphoto/eYKx68uOaEY5k9Jt4TrQPw/o.jpg",
"is_closed": false,
"url": "https://www.yelp.com/biz/strauss-brisbane?adjust_creative=0mCaOEYvfM9_oOaXgMuW6A&utm_campaign=yelp_api_v3&utm_medium=api_v3_business_search&utm_source=0mCaOEYvfM9_oOaXgMuW6A",
"review_count": 33,
"categories": [
{
"alias": "cafes",
"title": "Cafes"
}
],
"rating": 4.5,
"coordinates": {
"latitude": -27.469804,
"longitude": 153.027384
},
"transactions": [],
"price": "$",
"location": {
"address1": "189 Elizabeth St",
"address2": "",
"address3": "",
"city": "Brisbane",
"zip_code": "4000",
"country": "AU",
"state": "QLD",
"display_address": [
"189 Elizabeth St",
"Brisbane Queensland 4000",
"Australia"
]
},
"phone": "[phone]",
"display_phone": "[phone]",
"distance": 247.3760157828213
}
}
And this is json response for individual BusinessDetail.
{
"id": "I1D8NHvMWf8oMYceTyLlHg",
"name": "John Mills Himself",
"image_url": "https://s3-media3.fl.yelpcdn.com/bphoto/OH84e6eP8zpzBECF0WvTXA/o.jpg",
"is_claimed": false,
"is_closed": false,
"url": "https://www.yelp.com/biz/john-mills-himself-brisbane?adjust_creative=0mCaOEYvfM9_oOaXgMuW6A&utm_campaign=yelp_api_v3&utm_medium=api_v3_business_lookup&utm_source=0mCaOEYvfM9_oOaXgMuW6A",
"phone": "",
"display_phone": "",
"review_count": 55,
"categories": [
{
"alias": "coffee",
"title": "Coffee & Tea"
},
{
"alias": "bakeries",
"title": "Bakeries"
},
{
"alias": "wine_bars",
"title": "Wine Bars"
}
],
"rating": 4.5,
"location": {
"address1": "40 Charlotte St",
"address2": "",
"address3": "",
"city": "Brisbane",
"zip_code": "4000",
"country": "AU",
"state": "QLD",
"display_address": [
"40 Charlotte St",
"Brisbane Queensland 4000",
"Australia"
],
"cross_streets": ""
},
"coordinates": {
"latitude": -27.47151,
"longitude": 153.025654
},
"photos": [
"https://s3-media3.fl.yelpcdn.com/bphoto/OH84e6eP8zpzBECF0WvTXA/o.jpg",
"https://s3-media1.fl.yelpcdn.com/bphoto/L8dJYv1GCW1m5IvD0M3qXw/o.jpg",
"https://s3-media4.fl.yelpcdn.com/bphoto/oUH4cJmPRuAs_jv_xRtXQg/o.jpg"
],
"price": "$",
"hours": [
{
"open": [
{
"is_overnight": false,
"start": "0630",
"end": "1530",
"day": 0
},
{
"is_overnight": false,
"start": "0630",
"end": "1530",
"day": 1
},
{
"is_overnight": false,
"start": "1600",
"end": "2100",
"day": 1
},
{
"is_overnight": false,
"start": "0630",
"end": "1530",
"day": 2
},
{
"is_overnight": false,
"start": "1600",
"end": "2100",
"day": 2
},
{
"is_overnight": false,
"start": "0630",
"end": "1530",
"day": 3
},
{
"is_overnight": false,
"start": "1600",
"end": "2330",
"day": 3
},
{
"is_overnight": false,
"start": "0630",
"end": "1530",
"day": 4
},
{
"is_overnight": false,
"start": "1600",
"end": "2330",
"day": 4
},
{
"is_overnight": false,
"start": "1600",
"end": "2330",
"day": 5
}
],
"hours_type": "REGULAR",
"is_open_now": true
}
]
}
As you can see, BusinessDetail has exactly same info as Business at the top and I'd like to change BusinessDetail like below.
struct BusinessDetail {
let business: Business
let isClaimed: Bool
let isClosed: Bool
let url: URL
let phone: String?
let photoURLs: [URL]
var hours: [Hours]?
}
However, I am not sure if it is technically possible.

Answer 1

Here's a conceptual example, but you can apply the same principle to your case, with the following JSON:
{ "a": 1, "b": 2, "c": "three" }
and these models:
struct Smaller: Decodable {
var a, b: Int
}
struct Larger: Decodable {
var smaller: Smaller
var c: String
}
Decoding Smaller doesn't need any extra work (i.e. no need to manually implement the init(from: Decoder) initializer):
let decoder = JSONDecoder()
let small = try! decoder.decode(Smaller.self, from: jsonData)
But with Larger, you need to manually do this:
struct Larger: Decodable {
var smaller: Smaller
var c: String
enum CodingKeys: CodingKey {
case c
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
self.smaller = try Smaller.init(from: decoder)
self.c = try container.decode(String.self, forKey: .c)
}
}