[QL] Measure API Request Latency for PayPal Flows (#1292)

* Send start_time, end_time, and endpoint to FPTI for tracking API request latency in the PayPal flow
* Add new BTCoreAnalytics enum
* Add new BTAPITimingDelegate for sending start/end timing from BTHTTP to BTAPIClient
* Update UnitTests

Co-authored-by: Sammy Cannillo <[email protected]>

Braintree.xcodeproj/project.pbxproj

@@ -110,6 +110,7 @@
 		80CD34012A604307009545F5 /* MockCardinalSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80CD33FD2A603892009545F5 /* MockCardinalSession.swift */; };
 		80CF988529DB64D400D51979 /* BTLocalPaymentError.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80CF988429DB64D400D51979 /* BTLocalPaymentError.swift */; };
 		80D1638729E75CF1001D880E /* BTThreeDSecureClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80D1638529E75766001D880E /* BTThreeDSecureClient.swift */; };
+		80D280CD2BE9354B00762D27 /* Date+MillisecondTimestamp.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80D280CC2BE9354B00762D27 /* Date+MillisecondTimestamp.swift */; };
 		80E2460F29E492DF00945A1D /* BTLocalPaymentClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80E2460E29E492DF00945A1D /* BTLocalPaymentClient.swift */; };
 		80F86FF029FC2ED6003297FF /* Encodable+Dictionary.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80F86FEF29FC2ED6003297FF /* Encodable+Dictionary.swift */; };
 		80FF7D1A25881C03001C32EF /* BTThreeDSecureV2UICustomization_Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80FF7D1925881C03001C32EF /* BTThreeDSecureV2UICustomization_Tests.swift */; };
@@ -304,6 +305,8 @@
 		BEF1089129019DB9003B2FDA /* BTAPIClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = 570B93AF2853980C0041BAFE /* BTAPIClient.swift */; };
 		BEF177A62B51C7ED004F0F35 /* SEPADebitAccountsRequest.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF177A52B51C7ED004F0F35 /* SEPADebitAccountsRequest.swift */; };
 		BEF177A82B51D6A7004F0F35 /* SEPADebitRequest.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF177A72B51D6A7004F0F35 /* SEPADebitRequest.swift */; };
+		BEF388C12BE52CD2000965C8 /* BTCoreAnalytics.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF388C02BE52CD2000965C8 /* BTCoreAnalytics.swift */; };
+		BEF388C32BE9340C000965C8 /* BTAPITimingDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF388C22BE9340C000965C8 /* BTAPITimingDelegate.swift */; };
 		BEF3F17E27CE9EDF00072467 /* BTSEPADirectDebitClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF3F17127CE9E6C00072467 /* BTSEPADirectDebitClient.swift */; };
 		BEF5D2E6294A18B300FFD56D /* BTPayPalLineItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = BEF5D2E5294A18B300FFD56D /* BTPayPalLineItem.swift */; };
 		BEFD1AF4284F92130070076E /* PPRiskMagnes.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 9C36BD4226B30AA600F0A559 /* PPRiskMagnes.xcframework */; };
@@ -748,6 +751,7 @@
 		80CD33FF2A6042FC009545F5 /* CardinalSessionTestable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CardinalSessionTestable.swift; sourceTree = "<group>"; };
 		80CF988429DB64D400D51979 /* BTLocalPaymentError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTLocalPaymentError.swift; sourceTree = "<group>"; };
 		80D1638529E75766001D880E /* BTThreeDSecureClient.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTThreeDSecureClient.swift; sourceTree = "<group>"; };
+		80D280CC2BE9354B00762D27 /* Date+MillisecondTimestamp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Date+MillisecondTimestamp.swift"; sourceTree = "<group>"; };
 		80DBE69423A931A600373230 /* Helpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Helpers.swift; sourceTree = "<group>"; };
 		80E2460E29E492DF00945A1D /* BTLocalPaymentClient.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTLocalPaymentClient.swift; sourceTree = "<group>"; };
 		80F86FEF29FC2ED6003297FF /* Encodable+Dictionary.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Encodable+Dictionary.swift"; sourceTree = "<group>"; };
@@ -930,6 +934,8 @@
 		BEEB565A2AE9B3030029F264 /* BTIntegrationTestsConstants.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTIntegrationTestsConstants.swift; sourceTree = "<group>"; };
 		BEF177A52B51C7ED004F0F35 /* SEPADebitAccountsRequest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SEPADebitAccountsRequest.swift; sourceTree = "<group>"; };
 		BEF177A72B51D6A7004F0F35 /* SEPADebitRequest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SEPADebitRequest.swift; sourceTree = "<group>"; };
+		BEF388C02BE52CD2000965C8 /* BTCoreAnalytics.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTCoreAnalytics.swift; sourceTree = "<group>"; };
+		BEF388C22BE9340C000965C8 /* BTAPITimingDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTAPITimingDelegate.swift; sourceTree = "<group>"; };
 		BEF3F17127CE9E6C00072467 /* BTSEPADirectDebitClient.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTSEPADirectDebitClient.swift; sourceTree = "<group>"; };
 		BEF3F17C27CE9EC600072467 /* BraintreeSEPADirectDebit.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = BraintreeSEPADirectDebit.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		BEF5D2E5294A18B300FFD56D /* BTPayPalLineItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BTPayPalLineItem.swift; sourceTree = "<group>"; };
@@ -1206,12 +1212,14 @@
 			isa = PBXGroup;
 			children = (
 				80F4F4D529F8A628003EACB1 /* Analytics */,
+				BEBC6E5D2927CF59004E25A0 /* Braintree.h */,
 				570B93AF2853980C0041BAFE /* BTAPIClient.swift */,
 				BE24C67428E7491E0067B11A /* BTAPIClientAuthorization.swift */,
 				BE24C66D28E49A730067B11A /* BTAPIClientError.swift */,
 				BE24C67228E73E810067B11A /* BTAPIClientHTTPType.swift */,
 				BE9EC0972899CF040022EC63 /* BTAPIPinnedCertificates.swift */,
 				8075CBED2B1B735200CA6265 /* BTAPIRequest.swift */,
+				BEF388C22BE9340C000965C8 /* BTAPITimingDelegate.swift */,
 				579DAEC6286E064500FCE87F /* BTAppContextSwitchClient.swift */,
 				579DAEC4286E04A700FCE87F /* BTAppContextSwitcher.swift */,
 				BED00CAD28A5419900D74AEC /* BTBinData.swift */,
@@ -1243,12 +1251,12 @@
 				BEBD05212A1FE8BE0003C15C /* BTWebAuthenticationSession.swift */,
 				BEB9BF522A26872B00A3673E /* BTWebAuthenticationSessionClient.swift */,
 				BE698EA128AA8EEA001D9B10 /* ConfigurationCache.swift */,
+				80D280CC2BE9354B00762D27 /* Date+MillisecondTimestamp.swift */,
 				80F86FEF29FC2ED6003297FF /* Encodable+Dictionary.swift */,
-				80A6C6182B21205900416D50 /* UIApplication+URLOpener.swift */,
-				8053F05829FB2F700076F988 /* URL+IsPayPal.swift */,
 				BE7FA4C5291AC9B6003C6B63 /* Info.plist */,
-				BEBC6E5D2927CF59004E25A0 /* Braintree.h */,
 				62A746402B9255AC003D32FF /* PrivacyInfo.xcprivacy */,
+				80A6C6182B21205900416D50 /* UIApplication+URLOpener.swift */,
+				8053F05829FB2F700076F988 /* URL+IsPayPal.swift */,
 			);
 			path = BraintreeCore;
 			sourceTree = "<group>";
@@ -1329,6 +1337,7 @@
 			children = (
 				BEE2E4E329007FF100C03FDD /* BTAnalyticsService.swift */,
 				BEE2E4E5290080BD00C03FDD /* BTAnalyticsServiceError.swift */,
+				BEF388C02BE52CD2000965C8 /* BTCoreAnalytics.swift */,
 				800E78C329E0DD5300D1B0FC /* FPTIBatchData.swift */,
 			);
 			path = Analytics;
@@ -2816,6 +2825,7 @@
 				579DAEC7286E064500FCE87F /* BTAppContextSwitchClient.swift in Sources */,
 				8053F05929FB2F700076F988 /* URL+IsPayPal.swift in Sources */,
 				BEC3F11328A4401E0074DF0F /* BTHTTPError.swift in Sources */,
+				80D280CD2BE9354B00762D27 /* Date+MillisecondTimestamp.swift in Sources */,
 				574891EB286F7E4F0020DA36 /* BTClientMetadataIntegration.swift in Sources */,
 				8075CBEE2B1B735200CA6265 /* BTAPIRequest.swift in Sources */,
 				BE698EA428AD2C10001D9B10 /* BTCoreConstants.swift in Sources */,
@@ -2833,12 +2843,14 @@
 				BE24C67328E73E810067B11A /* BTAPIClientHTTPType.swift in Sources */,
 				BE9EC0982899CF040022EC63 /* BTAPIPinnedCertificates.swift in Sources */,
 				BEF1089029019CAE003B2FDA /* BTAnalyticsService.swift in Sources */,
+				BEF388C32BE9340C000965C8 /* BTAPITimingDelegate.swift in Sources */,
 				574891E9286F7D300020DA36 /* BTClientMetadataSource.swift in Sources */,
 				BED7493628579BAC0074C818 /* BTURLUtils.swift in Sources */,
 				BEBD05222A1FE8BE0003C15C /* BTWebAuthenticationSession.swift in Sources */,
 				BE698EA028AA8DCB001D9B10 /* BTHTTP.swift in Sources */,
 				BC17F9B428D23C5C004B18CC /* BTGraphQLMultiErrorNode.swift in Sources */,
 				5708E0A828809BC6007946B9 /* BTJSONError.swift in Sources */,
+				BEF388C12BE52CD2000965C8 /* BTCoreAnalytics.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

CHANGELOG.md

@@ -6,6 +6,8 @@
 ## 6.18.1 (2024-05-06)
 * Remove throttle delay in accessing configuration, added in v5.9.0
   * Move from URLCache to NSCache for configuration caching
+* BraintreePayPal
+  * Send `start_time`, `end_time`, and `endpoint` to FPTI for tracking API request latency
 
 ## 6.18.0 (2024-04-25)
 * BraintreePayPalNativeCheckout

Sources/BraintreeCore/Analytics/BTAnalyticsService.swift

@@ -30,17 +30,23 @@ class BTAnalyticsService: Equatable {
     func sendAnalyticsEvent(
         _ eventName: String,
         correlationID: String? = nil,
+        endpoint: String? = nil,
+        endTime: Int? = nil,
         errorDescription: String? = nil,
         linkType: String? = nil,
-        payPalContextID: String? = nil
+        payPalContextID: String? = nil,
+        startTime: Int? = nil
     ) {
         Task(priority: .background) {
             await performEventRequest(
                 eventName,
                 correlationID: correlationID,
+                endpoint: endpoint,
+                endTime: endTime,
                 errorDescription: errorDescription,
                 linkType: linkType,
-                payPalContextID: payPalContextID
+                payPalContextID: payPalContextID,
+                startTime: startTime
             )
         }
     }
@@ -49,17 +55,23 @@ class BTAnalyticsService: Equatable {
     func performEventRequest(
         _ eventName: String,
         correlationID: String? = nil,
+        endpoint: String? = nil,
+        endTime: Int? = nil,
         errorDescription: String? = nil,
         linkType: String? = nil,
-        payPalContextID: String? = nil
+        payPalContextID: String? = nil,
+        startTime: Int? = nil
     ) async {
-        let timestampInMilliseconds = Int(round(Date().timeIntervalSince1970 * 1000))
+        let timestampInMilliseconds = Date().utcTimestampMilliseconds
         let event = FPTIBatchData.Event(
             correlationID: correlationID,
+            endpoint: endpoint,
+            endTime: endTime,
             errorDescription: errorDescription,
             eventName: eventName,
             linkType: linkType,
             payPalContextID: payPalContextID,
+            startTime: startTime,
             timestamp: String(timestampInMilliseconds)
         )
 

Sources/BraintreeCore/Analytics/BTCoreAnalytics.swift

@@ -0,0 +1,6 @@
+import Foundation
+
+enum BTCoreAnalytics {
+
+    static let apiRequestLatency = "core:api-request-latency"
+}

Sources/BraintreeCore/Analytics/FPTIBatchData.swift

@@ -28,13 +28,16 @@ struct FPTIBatchData: Codable {
     struct Event: Codable {
 
         let correlationID: String?
+        let endpoint: String?
+        let endTime: Int?
         let errorDescription: String?
         let eventName: String
         /// The type of link the SDK will be handling, currently deeplink or universal
         let linkType: String?
         /// Used for linking events from the client to server side request
         /// This value will be PayPal Order ID, Payment Token, EC token, Billing Agreement, or Venmo Context ID depending on the flow
         let payPalContextID: String?
+        let startTime: Int?
         let timestamp: String
         let tenantName: String = "Braintree"
         let venmoInstalled: Bool = isVenmoAppInstalled()
@@ -47,6 +50,9 @@ struct FPTIBatchData: Codable {
             case payPalContextID = "paypal_context_id"
             case timestamp = "t"
             case tenantName = "tenant_name"
+            case startTime = "start_time"
+            case endTime = "end_time"
+            case endpoint = "endpoint"
             case venmoInstalled = "venmo_installed"
         }
     }

Sources/BraintreeCore/BTAPIClient.swift

@@ -2,7 +2,7 @@ import Foundation
 
 /// This class acts as the entry point for accessing the Braintree APIs via common HTTP methods performed on API endpoints.
 /// - Note: It also manages authentication via tokenization key and provides access to a merchant's gateway configuration.
-@objcMembers public class BTAPIClient: NSObject {
+@objcMembers public class BTAPIClient: NSObject, BTHTTPNetworkTiming {
 
     /// :nodoc: This typealias is exposed for internal Braintree use only. Do not use. It is not covered by Semantic Versioning and may change or be removed at any time.
     @_documentation(visibility: private)
@@ -19,6 +19,10 @@ import Foundation
     /// Client metadata that is used for tracking the client session
     public private(set) var metadata: BTClientMetadata
 
+    /// :nodoc: This property is exposed for internal Braintree use only. Do not use. It is not covered by Semantic Versioning and may change or be removed at any time.
+    @_documentation(visibility: private)
+    public var shouldSendAPIRequestLatency: Bool = false
+
     // MARK: - Internal Properties
 
     var configurationHTTP: BTHTTP?
@@ -65,12 +69,14 @@ import Foundation
 
             tokenizationKey = authorization
             configurationHTTP = BTHTTP(url: baseURL, tokenizationKey: authorization)
+            configurationHTTP?.networkTimingDelegate = self
         case .clientToken:
             do {
                 clientToken = try BTClientToken(clientToken: authorization)
 
                 guard let clientToken else { return nil }
                 configurationHTTP = try BTHTTP(clientToken: clientToken)
+                configurationHTTP?.networkTimingDelegate = self
             } catch {
                 print(errorString + " Missing analytics session metadata - will not send event " + error.localizedDescription)
                 return nil
@@ -470,6 +476,8 @@ import Foundation
             } else if let tokenizationKey, let baseURL {
                 http = BTHTTP(url: baseURL, tokenizationKey: tokenizationKey)
             }
+
+            http?.networkTimingDelegate = self
         }
 
         if graphQLHTTP == nil {
@@ -482,4 +490,19 @@ import Foundation
             }
         }
     }
+
+    // MARK: BTAPITimingDelegate conformance
+
+    func fetchAPITiming(path: String, startTime: Int, endTime: Int) {
+        let cleanedPath = path.replacingOccurrences(of: "/merchants/([A-Za-z0-9]+)/client_api", with: "", options: .regularExpression)
+
+        if (shouldSendAPIRequestLatency || path.contains("v1/configuration")) && cleanedPath != "/v1/tracking/batch/events" {
+            analyticsService?.sendAnalyticsEvent(
+                BTCoreAnalytics.apiRequestLatency,
+                endpoint: cleanedPath,
+                endTime: endTime,
+                startTime: startTime
+            )
+        }
+    }
 }

Sources/BraintreeCore/BTAPITimingDelegate.swift

@@ -0,0 +1,5 @@
+import Foundation
+
+protocol BTHTTPNetworkTiming: AnyObject {
+    func fetchAPITiming(path: String, startTime: Int, endTime: Int)
+}

Sources/BraintreeCore/BTHTTP.swift

@@ -2,7 +2,7 @@ import Foundation
 import Security
 
 /// Performs HTTP methods on the Braintree Client API
-class BTHTTP: NSObject, NSCopying, URLSessionDelegate {
+class BTHTTP: NSObject, NSCopying, URLSessionTaskDelegate {
 
     typealias RequestCompletion = (BTJSON?, HTTPURLResponse?, Error?) -> Void
 
@@ -14,12 +14,14 @@ class BTHTTP: NSObject, NSCopying, URLSessionDelegate {
 
     /// An array of pinned certificates, each an NSData instance consisting of DER encoded x509 certificates
     let pinnedCertificates: [NSData] = BTAPIPinnedCertificates.trustedCertificates()
+    let baseURL: URL
 
     /// DispatchQueue on which asynchronous code will be executed. Defaults to `DispatchQueue.main`.
     var dispatchQueue: DispatchQueue = DispatchQueue.main
-    let baseURL: URL
     var clientAuthorization: ClientAuthorization?
 
+    weak var networkTimingDelegate: BTHTTPNetworkTiming?
+
     /// Session exposed for testing
     lazy var session: URLSession = {
         let configuration: URLSessionConfiguration = URLSessionConfiguration.ephemeral
@@ -425,7 +427,7 @@ class BTHTTP: NSObject, NSCopying, URLSessionDelegate {
         }
     }
 
-    // MARK: - URLSessionDelegate conformance
+    // MARK: - URLSessionTaskDelegate conformance
 
     func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
         if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {
@@ -449,4 +451,18 @@ class BTHTTP: NSObject, NSCopying, URLSessionDelegate {
             completionHandler(.performDefaultHandling, nil)
         }
     }
+
+    func urlSession(_ session: URLSession, task: URLSessionTask, didFinishCollecting metrics: URLSessionTaskMetrics) {
+        metrics.transactionMetrics.forEach { transaction in
+            if let startDate = transaction.fetchStartDate,
+               let endDate = transaction.responseEndDate,
+               let path = transaction.request.url?.path {
+                networkTimingDelegate?.fetchAPITiming(
+                    path: path,
+                    startTime: startDate.utcTimestampMilliseconds,
+                    endTime: endDate.utcTimestampMilliseconds
+                )
+            }
+        }
+    }
 }

Sources/BraintreeCore/Date+MillisecondTimestamp.swift

@@ -0,0 +1,8 @@
+import Foundation
+
+extension Date {
+
+    var utcTimestampMilliseconds: Int {
+        Int(round(timeIntervalSince1970 * 1000))
+    }
+}

Sources/BraintreePayPal/BTPayPalClient.swift

@@ -45,6 +45,8 @@ import BraintreeDataCollector
     /// - Parameter apiClient: The API Client
     @objc(initWithAPIClient:)
     public init(apiClient: BTAPIClient) {
+        apiClient.shouldSendAPIRequestLatency = true
+
         self.apiClient = apiClient
         self.webAuthenticationSession = BTWebAuthenticationSession()
 

UnitTests/BraintreeCoreTests/Analytics/FPTIBatchData_Tests.swift

@@ -18,18 +18,24 @@ final class FPTIBatchData_Tests: XCTestCase {
     let eventParams = [
         FPTIBatchData.Event(
             correlationID: "fake-correlation-id-1",
+            endpoint: "/v1/paypal_hermes/setup_billing_agreement",
+            endTime: 111222333444555,
             errorDescription: "fake-error-description-1",
             eventName: "fake-event-1",
             linkType: "universal",
             payPalContextID: "fake-order-id",
+            startTime: 999888777666,
             timestamp: "fake-time-1"
         ),
         FPTIBatchData.Event(
             correlationID: nil,
+            endpoint: nil,
+            endTime: nil,
             errorDescription: nil,
             eventName: "fake-event-2",
             linkType: nil,
             payPalContextID: "fake-order-id-2",
+            startTime: nil,
             timestamp: "fake-time-2"
         )
     ]
@@ -93,5 +99,13 @@ final class FPTIBatchData_Tests: XCTestCase {
         XCTAssertNil(eventParams[1]["error_desc"])
         XCTAssertEqual(eventParams[0]["correlation_id"] as? String, "fake-correlation-id-1")
         XCTAssertNil(eventParams[1]["correlation_id"])
+        XCTAssertEqual(eventParams[0]["endpoint"] as? String, "/v1/paypal_hermes/setup_billing_agreement")
+        XCTAssertNil(eventParams[1]["endpoint"])
+        XCTAssertEqual(eventParams[0]["end_time"] as? Int, 111222333444555)
+        XCTAssertNil(eventParams[1]["end_time"])
+        XCTAssertEqual(eventParams[0]["start_time"] as? Int, 999888777666)
+        XCTAssertNil(eventParams[1]["start_time"])
     }
 }
+
+

UnitTests/BraintreeCoreTests/Analytics/FakeAnalyticsService.swift

@@ -2,15 +2,20 @@ import Foundation
 @testable import BraintreeCore
 
 class FakeAnalyticsService: BTAnalyticsService {
-    var lastEvent: String = ""
+    var lastEvent: String? = nil
+    var endpoint: String? = nil
 
     override func sendAnalyticsEvent(
         _ eventName: String,
         correlationID: String? = nil,
+        endpoint: String? = nil,
+        endTime: Int? = nil,
         errorDescription: String? = nil,
         linkType: String? = nil,
-        payPalContextID: String? = nil
+        payPalContextID: String? = nil,
+        startTime: Int? = nil
     ) {
         self.lastEvent = eventName
+        self.endpoint = endpoint
     }
 }