Merge pull request #1474 from stripe-ios/kg-addstatuscode

StripeCore: added support for seeing HTTP response status code as part of StripeServiceError.

StripeCore/StripeCore/Source/API Bindings/STPAPIClient.swift

@@ -433,16 +433,17 @@ extension STPAPIClient {
         request: URLRequest,
         completion: @escaping (Result<T, Error>) -> Void
     ) {
-        urlSession.stp_performDataTask(with: request, completionHandler: { (data, _, error) in
+        urlSession.stp_performDataTask(with: request, completionHandler: { (data, response, error) in
             DispatchQueue.main.async {
-                completion(STPAPIClient.decodeResponse(data: data, error: error))
+                completion(STPAPIClient.decodeResponse(data: data, error: error, response: response))
             }
         })
     }
 
     @_spi(STP) public static func decodeResponse<T: Decodable>(
         data: Data?,
-        error: Error?
+        error: Error?,
+        response: URLResponse?
     ) -> Result<T, Error> {
         if let error = error {
             return .failure(error)
@@ -454,15 +455,15 @@ extension STPAPIClient {
         do {
             /// HACK: We must first check if EmptyResponses contain an error since it'll always parse successfully.
             if T.self == EmptyResponse.self,
-               let decodedStripeError = decodeStripeErrorResponse(data: data) {
+               let decodedStripeError = decodeStripeErrorResponse(data: data, response: response) {
                 return .failure(decodedStripeError)
             }
 
             let decodedObject: T = try StripeJSONDecoder.decode(jsonData: data)
             return .success(decodedObject)
         } catch {
             // Try decoding the error from the service if one is available
-            if let decodedStripeError = decodeStripeErrorResponse(data: data) {
+            if let decodedStripeError = decodeStripeErrorResponse(data: data, response: response) {
                 return .failure(decodedStripeError)
             } else {
                 // Return decoding error directly
@@ -472,11 +473,12 @@ extension STPAPIClient {
     }
 
     /// Decodes request data to see if it can be parsed as a Stripe error
-    private static func decodeStripeErrorResponse(data: Data) -> StripeError? {
+    private static func decodeStripeErrorResponse(data: Data, response: URLResponse?) -> StripeError? {
         var decodedError: StripeError?
 
         if let decodedErrorResponse: StripeAPIErrorResponse = try? StripeJSONDecoder.decode(jsonData: data),
-           let apiError = decodedErrorResponse.error {
+           var apiError = decodedErrorResponse.error {
+            apiError.statusCode = (response as? HTTPURLResponse)?.statusCode
             decodedError = StripeError.apiError(apiError)
         }
 

StripeCore/StripeCore/Source/API Bindings/StripeServiceError.swift

@@ -21,6 +21,8 @@ import Foundation
     @_spi(STP) public var message: String?
     /// If the error is parameter-specific, the parameter related to the error. For example, you can use this to display a message near the correct form field.
     @_spi(STP) public var param: String?
+    /// The response’s HTTP status code.
+    @_spi(STP) public var statusCode: Int?
 
     // More information may be available in `allResponseFields`, including
     // the PaymentIntent or PaymentMethod.

StripeCore/StripeCoreTestUtils/Mocks/MockData.swift

@@ -24,7 +24,7 @@ public extension MockData {
     }
 
     func make() throws -> ResponseType {
-        let result: Result<ResponseType, Error> = STPAPIClient.decodeResponse(data: try data(), error: nil)
+        let result: Result<ResponseType, Error> = STPAPIClient.decodeResponse(data: try data(), error: nil, response: nil)
         switch result {
         case .success(let response):
             return response

StripeCore/StripeCoreTests/API Bindings/STPAPIClient+EmptyResponseTest.swift

@@ -20,19 +20,34 @@ class STPAPIClient_EmptyResponseTest: XCTestCase {
         ]
 
         let responseData = try JSONSerialization.data(withJSONObject: response, options: [])
-        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(data: responseData, error: nil)
+        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(
+            data: responseData,
+            error: nil,
+            response: HTTPURLResponse(
+                url: URL(string: "https://www.stripe.com")!,
+                statusCode: 400,
+                httpVersion: nil,
+                headerFields: nil
+            )
+        )
 
-        guard case .failure = result else {
+        switch result {
+        case .success(_):
             XCTFail("The request should not have succeeded")
-            return
+        case .failure(let error):
+            if let stripeError = error as? StripeError, case .apiError(let apiError) = stripeError {
+                XCTAssert(apiError.statusCode == 400, "expected status code to be set")
+            } else {
+                XCTFail("The error should have been an `.apiError`")
+            }
         }
     }
 
     /// Response is an empty response; Error is not nil
     /// Should result in a failure
     func testEmptyResponse_WithError() throws {
         let responseData = try JSONSerialization.data(withJSONObject: [:], options: [])
-        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(data: responseData, error: NSError.stp_genericConnectionError())
+        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(data: responseData, error: NSError.stp_genericConnectionError(), response: nil)
 
         guard case .failure = result else {
             XCTFail("The request should not have succeeded")
@@ -44,7 +59,7 @@ class STPAPIClient_EmptyResponseTest: XCTestCase {
     /// Should result in a success
     func testEmptyResponse_NoError() throws {
         let responseData = try JSONSerialization.data(withJSONObject: [:], options: [])
-        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(data: responseData, error: nil)
+        let result: Result<EmptyResponse, Error> = STPAPIClient.decodeResponse(data: responseData, error: nil, response: nil)
 
         guard case .success = result else {
             XCTFail("The request should have succeeded")