Merge pull request #44 from RocketCommunicationsInc/cache-improvements

Cache improvements
RocketCommunicationsInc · Jul 7, 2023 · a5a00f0 · a5a00f0
2 parents a4d71f5 + 26320e3
commit a5a00f0
Showing 1 changed file with 26 additions and 6 deletions.
diff --git a/Shared/Data/NetworkManager.swift b/Shared/Data/NetworkManager.swift
@@ -106,17 +106,32 @@ class NetworkManager:ObservableObject
     // Convert into an array of Launch objects
     private func loadLaunches(_ timePeriod:TimePeriod) async
     {
-        // if the cached data is usable process that data, otherwise download new data
-        if cacheIsUsable(timePeriod){
-            if launchesEmpty(timePeriod) // no need to reload existing cached data
+        // if no data is available, probably startup or first run
+        if launchesEmpty(timePeriod)
+        {
+            // if ANY cache is available, even if old
+            if cacheIsAvailable(timePeriod)
             {
+                // load the cache, even if old
                 loadFromCache(timePeriod)
             }
         }
-        else {
+
+        // check if cache is old, begin to load from network
+        if !cacheIsUsable(timePeriod)
+        {
             await loadFromNetwork(timePeriod)
         }
     }
+
+    // return true if there is some data in the cache
+    func cacheIsAvailable(_ timePeriod:TimePeriod)->Bool {
+
+        let cacheSize = timePeriod == .upcoming ? upcomingDataCache.count : recentDataCache.count
+
+        return cacheSize > 1
+    }
+
 
     // return true if the cache for timePeriod is less than refreshInterval minutes old, and there is some data in the cache
     func cacheIsUsable(_ timePeriod:TimePeriod)->Bool {
@@ -129,7 +144,6 @@ class NetworkManager:ObservableObject
 
     // load from cached data for timePeriod
     func loadFromCache(_ timePeriod:TimePeriod) {
-        print("good cache found")
         let data = timePeriod == .upcoming ? upcomingDataCache : recentDataCache
         let myLaunches = try! JSONDecoder().decode(LaunchReplies.self, from: data)
 
@@ -164,7 +178,13 @@ class NetworkManager:ObservableObject
             guard (200...299).contains(status) else {
                 if (status == 429) {
                     // handle "Too Many Requests" error
-                    self.prepareAlert(title: "Too Many Requests", message: HTTPURLResponse.localizedString(forStatusCode: status))
+                    // Do not show an alert for this error. Because launches uses the free version
+                    // of the API, this error can rise often with multiple users on the same IP address.
+                    // Instead, just fail silently, hopefully displaying some cached data.
+                    // A better solution would be to show a small note somewhere in the display
+                    // indicating that the data is stale.
+                    // Even better, paying for API access.
+                    //self.prepareAlert(title: "Too Many Requests", message: HTTPURLResponse.localizedString(forStatusCode: status))
                 }
                 else {
                     // handle generic error