Swiftで、URLSessionを用いたHTTP通信がうまくいかない

前提・実現したいこと

URLSessionを使ってホットペッパーAPIから店舗情報をJSON形式で取得し、デコードしてインスタンスに入れたい。

発生している問題・エラーメッセージ

print関数にインスタンスを渡しても、何も出力されない。エラーは出ていない。

該当のソースコード

Swift
1import UIKit
2import MapKit
3import Foundation
4
5class MapController: UIViewController {
6    
7    var searchText:String = String() //遷移前の画面で入力されたテキスト。これを位置情報として扱う
8    
9    var geocoder = CLGeocoder()
10    
11    @IBOutlet weak var mapView: MKMapView!
12    
13    @IBOutlet weak var tableView: UITableView!
14    
15    override func viewDidLoad() {
16        super.viewDidLoad()
17
18        // Do any additional setup after loading the view.
19        
20        geocoder.geocodeAddressString(searchText, completionHandler:{(placemarks, error) in
21            
22            if let center = placemarks?.first?.location?.coordinate {
23                
24                let latitude = String(center.latitude).addingPercentEncoding(withAllowedCharacters:.urlQueryAllowed) //searchTextに入力された位置の緯度
25                
26                let longitude = String(center.longitude).addingPercentEncoding(withAllowedCharacters:.urlQueryAllowed) //searchTextに入力された位置の経度
27                
28                if let url = URL(string:"https://webservice.recruit.co.jp/hotpepper/gourmet/v1/?key=e506073f251a9ca1&keyword=("カラオケ".addingPercentEncoding(withAllowedCharacters:.urlQueryAllowed))&lat=(latitude)&lng=( longitude)&range=3&format=json") { //searchTextに入力された位置情報から半径1km以内のカラオケ店を検索
29                    
30                    let request = URLRequest(url:url)
31                    
32                    let session = URLSession(configuration:.default, delegate:nil, delegateQueue:OperationQueue.main)
33                    
34                    let download = session.dataTask(with:request, completionHandler:{(data, response, error) in
35                        
36                        session.finishTasksAndInvalidate()
37                        
38                        do {
39                        
40                        let decoder = JSONDecoder()
41                        
42                            let karaoke = try decoder.decode(Karaoke.self, from:data!)
43                            
44                            print(karaoke) //karaokeの内容が出力されない
45                            
46                        } catch {
47                            
48                            print("エラーが発生しました")
49                            
50                        }
51                        
52                    })
53                    
54                    download.resume()
55                    
56                }
57                
58            }
59            
60            
61        })
62        
63
64        
65        
66
67        
68    }
69    
70
71    /*
72    // MARK: - Navigation
73
74    // In a storyboard-based application, you will often want to do a little preparation before navigation
75    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
76        // Get the new view controller using segue.destination.
77        // Pass the selected object to the new view controller.
78    }
79    */
80
81}
82
83struct Karaoke:Codable {
84    
85    let result:Result?
86    
87    struct Result:Codable {
88        
89        let shop:[Shop]?
90     
91        struct Shop:Codable {
92            
93            let access:String?
94            
95            let address:String?
96            
97            let budget:Budget?
98            
99            let budget_memo:String?
100            
101            let capacity:Int?
102            
103            let card:String?
104            
105            let `catch`:String?
106            
107            let free_drink:String?
108            
109            let free_food:String?
110            
111            let genre:Genre?
112            
113            let id:String?
114            
115            let large_Area:LargeArea?
116            
117            let lat:Int?
118            
119            let lng:Int?
120            
121            let logo_image:String?
122            
123            let middle_image:MiddleImage?
124            
125            let mobile_access:String?
126            
127            let name:String?
128            
129            let name_kana:String?
130            
131            let non_smoking:String?
132            
133            let open:String?
134            
135            let parking:String?
136            
137            let photo:Photo?
138            
139            let private_room:String?
140            
141            let small_area:SmallArea?
142            
143            let station_name:String?
144            
145            let wifi:String?
146            
147            struct Budget:Codable {
148                
149                let average:String?
150                
151                let name:String?
152                
153            }
154            
155            struct Genre:Codable {
156                
157                let `catch`:String?
158                
159            }
160            
161            struct LargeArea:Codable {
162                
163                let name:String?
164                
165            }
166            
167            struct MiddleImage:Codable {
168                
169                let name:String?
170                
171            }
172            
173            struct Photo:Codable {
174                
175                let mobile:Mobile?
176                
177                struct Mobile:Codable {
178                    
179                    let l:String?
180                    
181                    let s:String?
182                    
183                }
184                
185            }
186            
187            struct SmallArea:Codable {
188                
189                let name:String?
190                
191            }
192            
193        }
194        
195    }
196    
197}