Support dispatching multiple events at the same time

Naive non-thread safe implementation

Author: andrewjl-mux

Sources/MuxUploadSDK/InternalUtilities/Reporting/Reporter.swift

@@ -10,7 +10,7 @@ import UIKit
 
 class Reporter: NSObject {
     var session: URLSession?
-    var pendingUploadEvent: UploadEvent?
+    var pendingEvents: [ObjectIdentifier: Codable] = [:]
 
     var jsonEncoder: JSONEncoder
 
@@ -68,7 +68,7 @@ class Reporter: NSObject {
             regionCode = locale.regionCode
         }
 
-        self.pendingUploadEvent = UploadEvent(
+        let event = UploadEvent(
             startTime: startTime,
             endTime: endTime,
             fileSize: fileSize,
@@ -83,34 +83,38 @@ class Reporter: NSObject {
             regionCode: regionCode
         )
 
-        let request = self.generateRequest(url: URL(string: "https://mobile.muxanalytics.com")!)
-
-        let dataTask = session?.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
-            self.pendingUploadEvent = nil
-        })
-        dataTask?.resume()
+        send(
+            event: event,
+            url: url
+        )
     }
 
-    func serializePendingEvent() throws -> Data {
-        return try jsonEncoder.encode(pendingUploadEvent)
-    }
+    func send<Event: Codable>(
+        event: Event,
+        url: URL
+    ) {
+        guard let httpBody = try? jsonEncoder.encode(event) else {
+            return
+        }
 
-    private func generateRequest(url: URL) -> URLRequest {
-        let request = NSMutableURLRequest(url: url,
-                                          cachePolicy: .useProtocolCachePolicy,
-                                          timeoutInterval: 10.0)
-        request.httpMethod = "POST"
-        request.setValue("application/json", forHTTPHeaderField: "Accept")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        let request = NSMutableURLRequest.make(
+            url: url,
+            httpBody: httpBody
+        )
+
+        guard let dataTask = session?.dataTask(
+            with: request as URLRequest
+        ) else {
+            return
+        }
+
+        let taskID = ObjectIdentifier(dataTask)
 
-        // FIXME: If this fails, an event without a payload
-        // is sent which probably isn't what we want
-        do {
-            let jsonData = try serializePendingEvent()
-            request.httpBody = jsonData
-        } catch _ as NSError {}
+        pendingEvents[
+            taskID
+        ] = event
 
-        return request as URLRequest
+        dataTask.resume()
     }
 }
 
@@ -245,12 +249,30 @@ extension Reporter {
 // TODO: Implement as a separate object so the URLSession
 // can become non-optional, which removes a bunch of edge cases
 extension Reporter: URLSessionDelegate, URLSessionTaskDelegate {
-    public func urlSession(_ session: URLSession, task: URLSessionTask, willPerformHTTPRedirection response: HTTPURLResponse, newRequest request: URLRequest, completionHandler: @escaping (URLRequest?) -> Swift.Void) {
-        if(self.pendingUploadEvent != nil) {
-            if let redirectUrl = request.url {
-                let request = self.generateRequest(url: redirectUrl)
-                completionHandler(request)
+    func urlSession(_ session: URLSession, task: URLSessionTask, willPerformHTTPRedirection response: HTTPURLResponse, newRequest request: URLRequest, completionHandler: @escaping (URLRequest?) -> Swift.Void) {
+
+        if let pendingEvent = pendingEvents[ObjectIdentifier(task)], let redirectURL = request.url {
+
+            guard let httpBody = try? jsonEncoder.encode(pendingEvent) else {
+                completionHandler(nil)
+                return
             }
+
+            // TODO: This can be URLRequest instead of NSMutableURLRequest
+            // test URLRequest-based construction in case
+            // for any weirdness
+            let request = NSMutableURLRequest.make(
+                url: redirectURL,
+                httpBody: httpBody
+            )
+
+            completionHandler(request as URLRequest)
         }
     }
+
+    func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
+        pendingEvents[
+            ObjectIdentifier(task)
+        ] = nil
+    }
 }