More essential user interaction topics

Week02/doRequestFunction.swift

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+// Web API requestor, returns a "Courses" object (or nil)
+// This is simple example, and is NOT a best practice
+// The function is synchronous and will block the UI
+// Students can use this code as-is,
+// but it assumes the "package" struct is named "PackageCourses"
+func doRequest(url: URL) -> PackageCourses? {
+
+    // A do-catch statement handles errors
+    // For the following, if there is an error, "catch" returns nil
+    do {
+
+        // Attempt to get the data from the web API
+        let data = try Data(contentsOf: url)
+
+        // Create and configure a JSON decoder
+        let decoder = JSONDecoder()
+        decoder.dateDecodingStrategy = .iso8601
+
+        // Attempt to decode the data into a "PackageCourses" object
+        let result = try decoder.decode(PackageCourses.self, from: data)
+
+        // If it gets this far, it has been successful
+        return result
+    }
+    catch {
+        // Uh oh, error
+        print("Request error: \(error.localizedDescription)")
+        return nil
+    }
+}