From ee14ea94d7170cf8838683812c15c550a8867bbc Mon Sep 17 00:00:00 2001
From: Chris Leonavicius <chris.leonavicius@amplitude.com>
Date: Thu, 15 Aug 2024 12:14:05 -0700
Subject: [PATCH] fix: set offline when receiving certain error responses

---
 Sources/Amplitude/Utilities/HttpClient.swift  | 15 ++++++++++---
 .../Utilities/HttpClientTests.swift           | 21 +++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/Sources/Amplitude/Utilities/HttpClient.swift b/Sources/Amplitude/Utilities/HttpClient.swift
index 1e8e7cc4..72964e2e 100644
--- a/Sources/Amplitude/Utilities/HttpClient.swift
+++ b/Sources/Amplitude/Utilities/HttpClient.swift
@@ -37,10 +37,19 @@ class HttpClient {
             let request = try getRequest()
             let requestData = getRequestData(events: events)
 
-            sessionTask = session.uploadTask(with: request, from: requestData) { [callbackQueue] data, response, error in
+            sessionTask = session.uploadTask(with: request, from: requestData) { [callbackQueue, configuration] data, response, error in
                 callbackQueue.async {
-                    if error != nil {
-                        completion(.failure(error!))
+                    if let error = error {
+                        let nsError = error as NSError
+                        if nsError.domain == NSURLErrorDomain {
+                            switch nsError.code {
+                            case NSURLErrorCannotConnectToHost, NSURLErrorNetworkConnectionLost, NSURLErrorCannotFindHost, NSURLErrorAppTransportSecurityRequiresSecureConnection:
+                                configuration.offline = true
+                            default:
+                                break
+                            }
+                        }
+                        completion(.failure(error))
                     } else if let httpResponse = response as? HTTPURLResponse {
                         switch httpResponse.statusCode {
                         case 1..<300:
diff --git a/Tests/AmplitudeTests/Utilities/HttpClientTests.swift b/Tests/AmplitudeTests/Utilities/HttpClientTests.swift
index 3af5c5c0..63159ac2 100644
--- a/Tests/AmplitudeTests/Utilities/HttpClientTests.swift
+++ b/Tests/AmplitudeTests/Utilities/HttpClientTests.swift
@@ -86,4 +86,25 @@ final class HttpClientTests: XCTestCase {
         }
         _ = XCTWaiter.wait(for: [asyncExpectation], timeout: 5)
     }
+
+    func testUploadWithCannotConnectToHostError() {
+        let config = Configuration(apiKey: "fake", serverUrl: "http://localhost:3000", offline: false)
+        let httpClient = HttpClient(configuration: config, diagnostics: diagonostics)
+        let uploadExpectation = expectation(description: "Did Call Upload")
+        let event = BaseEvent(userId: "unit-test user", eventType: "unit-test event")
+
+        _ = httpClient.upload(events: "[\(event.toString())]") { result in
+            switch result {
+            case .success:
+                XCTFail("Expected failure")
+            case .failure(let error):
+                XCTAssertEqual((error as NSError).code, NSURLErrorCannotConnectToHost)
+            }
+
+            uploadExpectation.fulfill()
+        }
+
+        waitForExpectations(timeout: 5)
+        XCTAssertEqual(config.offline, true)
+    }
 }