feat: support calibrate local timestamp (#57)

Co-authored-by: xiaoweii <xiaoweii@amazom.com>

Sources/Clickstream/Network/NetRequest.swift

@@ -33,6 +33,7 @@ enum NetRequest {
             URLQueryItem(name: "appId", value: configuration.appId),
             URLQueryItem(name: "compression", value: compression),
             URLQueryItem(name: "event_bundle_sequence_id", value: String(describing: bundleSequenceId)),
+            URLQueryItem(name: "upload_timestamp", value: String(describing: Date().millisecondsSince1970)),
             URLQueryItem(name: "hashCode", value: requestData.hashCode())
         ]
 

Tests/ClickstreamTests/Clickstream/EventRecorderTest.swift

@@ -16,6 +16,7 @@ class EventRecorderTest: XCTestCase {
     let testFailEndpoint = "http://localhost:8080/collect/fail"
     let testSuccessWithDelayEndpoint = "http://localhost:8080/collect/success/delay"
     let testHashCodeEndpoint = "http://localhost:8080/collect/hashcode"
+    let testUploadTimestampEndpoint = "http://localhost:8080/collect/timestamp"
     var dbUtil: ClickstreamDBProtocol!
     var clickstreamEvent: ClickstreamEvent!
     var eventRecorder: EventRecorder!
@@ -426,6 +427,22 @@ class EventRecorderTest: XCTestCase {
         let result = NetRequest.uploadEventWithURLSession(eventsJson: eventJson, configuration: clickstream.configuration, bundleSequenceId: 1)
         XCTAssertTrue(result)
     }
+
+    func testVerifyUploadTimestampInRequestParameter() {
+        clickstream.configuration.endpoint = testUploadTimestampEndpoint
+        server["/collect/timestamp"] = { request in
+            let queryParams = request.queryParams
+            // swift lambda for get the upload_timestamp value in queryParams dictionary
+            let uploadTimestamp = queryParams.first(where: { $0.0 == "upload_timestamp" })?.1
+            let requestUploadTimestamp = Int64(uploadTimestamp!)!
+            if Date().millisecondsSince1970 - requestUploadTimestamp < 5_000 {
+                return .ok(.text("Success"))
+            }
+            return .badRequest(.text("Fail"))
+        }
+        let result = NetRequest.uploadEventWithURLSession(eventsJson: "[]", configuration: clickstream.configuration, bundleSequenceId: 1)
+        XCTAssertTrue(result)
+    }
 }
 
 extension String {