StewartLynch · May 9, 2021 15:45 · May 9, 2021 · May 9, 2021
diff --git a/Pagination Problem b/Pagination Problem
@@ -110,6 +110,7 @@ func printAllTitles(completion: @escaping ([Items]) -> Void) {
         if nextPageToken != nil {
             // Here is where I am stuck.  I need to keep calling getAllItems until nextPageToken is no longer nil so that I can append all of the items to the allItems array and then execute the completion
             // I am forcing completion here so that you can see that I get the first 20 in the set
+            // NOTE ****** If I don't complete here, I am in an infinite loop and my daily API quota exceeds and I can't work on it again until the next day
             completion(foundItems)
         } else {
             completion(foundItems)

diff --git a/Pagination Problem b/Pagination Problem
@@ -0,0 +1,125 @@
+import Foundation
+
+// Here is the codable model that I am trying to decode the feed into
+struct Feed: Codable {
+    let items: [Items]
+    let pageInfo: PageInfo
+    let nextPageToken: String?
+}
+
+struct PageInfo: Codable {
+    let totalResults: Int
+    let resultsPerPage: Int
+}
+
+struct Items: Codable, Identifiable {
+    struct Snippet: Codable {
+        struct Thumbnails: Codable {
+            struct Default: Codable {
+                let url: URL
+            }
+            let `default`: Default?
+        }
+
+        struct ResourceId: Codable {
+            let videoId: String
+        }
+
+        let publishedAt: Date
+        let title: String
+        let description: String
+        let thumbnails: Thumbnails
+        let resourceId: ResourceId?
+        let channelId: String?
+    }
+
+    let id: String
+    let snippet: Snippet
+
+}
+
+// Here is a sample endpoint. I have specified maxResults here as 20, because I know that there are 50items in this playlist and so there will be pagination involved meaning that for the first 4 requests, the Feed object's nextPageToken will not be nil
+let endpoint = "https://www.googleapis.com/youtube/v3/playlistItems?part=snippet%2CcontentDetails&maxResults=20&playlistId=PLBn01m5Vbs4C8jeAmLZxk9kZ59lYtxnHW&key=AIzaSyAfF93xIFQEVYXjci2P3VYdhIWNFG9n7cw"
+
+// This is what I currently use for my APIServce to make a request to get the JSON
+enum APIService {
+    struct ErrorType: Identifiable {
+        let id = UUID()
+        let error: APIError
+    }
+        public enum APIError: Error {
+             case error(_ errorString: String)
+         }
+         public static func getJSON<T: Decodable>(urlString: String,
+                                    dateDecodingStategy: JSONDecoder.DateDecodingStrategy = .deferredToDate,
+                                    keyDecodingStrategy: JSONDecoder.KeyDecodingStrategy = .useDefaultKeys,
+                                    completion: @escaping (Result<T,APIError>) -> Void) {
+             guard let url = URL(string: urlString) else {
+                completion(.failure(.error("Invalid URL")))
+                 return
+             }
+             let request = URLRequest(url: url)
+             URLSession.shared.dataTask(with: request) { (data, response, error) in
+                 if let error = error {
+                     completion(.failure(.error("URLError: \(error.localizedDescription)")))
+                     return
+                 }
+                 guard let data = data else {
+                     completion(.failure(.error("Error: Data is corrupt.")))
+                     return
+                 }
+                 let decoder = JSONDecoder()
+                 decoder.dateDecodingStrategy = dateDecodingStategy
+                 decoder.keyDecodingStrategy = keyDecodingStrategy
+                 guard let decodedData = try? decoder.decode(T.self, from: data) else {
+                     completion(.failure(.error("Error: decoding data.")))
+                     return
+                 }
+                 completion(.success(decodedData))
+             }.resume()
+         }
+    }
+
+// So, when when I want to retrieve the data, I do this.
+
+var allItems = [Items]()
+// Here is a function that I use to retrieve the items and populate the allItems array
+func getAllItems(nextPageToken:String? = nil, completion: @escaping (Feed) -> Void) {
+    var urlString = endpoint
+    if let nextPageToken = nextPageToken {
+        urlString = endpoint + "&pageToken=\(nextPageToken)"
+    }
+    APIService.getJSON(urlString: urlString,dateDecodingStategy: .iso8601) {  (result: Result<Feed, APIService.APIError>) in
+        switch result {
+        case .success(let feed):
+            completion(feed)
+        case .failure(let error):
+            print(error.localizedDescription)
+        }
+    }
+}
+
+
+// Example processing of retrieved items
+
+func printAllTitles(completion: @escaping ([Items]) -> Void) {
+    var foundItems = [Items]()
+    getAllItems { feed in
+        foundItems += feed.items
+        let nextPageToken = feed.nextPageToken
+        if nextPageToken != nil {
+            // Here is where I am stuck.  I need to keep calling getAllItems until nextPageToken is no longer nil so that I can append all of the items to the allItems array and then execute the completion
+            // I am forcing completion here so that you can see that I get the first 20 in the set
+            completion(foundItems)
+        } else {
+            completion(foundItems)
+        }
+    }
+}
+
+printAllTitles { items in
+   allItems = items
+    for item in allItems {
+        print(item.snippet.title)
+    }
+}