feat: handle errors in 200 response from S3

IntegrationTests/Services/AWSS3IntegrationTests/S3ErrorIn200Test.swift

@@ -0,0 +1,64 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+import XCTest
+import AWSS3
+import AWSClientRuntime
+import AwsCommonRuntimeKit
+import ClientRuntime
+
+public class MockHttpClientEngine: HttpClientEngine {
+
+    // Public initializer
+    public init() {}
+
+    func successHttpResponse(request: SdkHttpRequest) -> HttpResponse {
+        let errorResponsePayload = """
+            <Error>
+                <Code>SlowDown</Code>
+                <Message>Please reduce your request rate.</Message>
+                <RequestId>K2H6N7ZGQT6WHCEG</RequestId>
+                <HostId>WWoZlnK4pTjKCYn6eNV7GgOurabfqLkjbSyqTvDMGBaI9uwzyNhSaDhOCPs8paFGye7S6b/AB3A=</HostId>
+            </Error>
+        """
+        return HttpResponse(
+            headers: request.headers,
+            body: ByteStream.data(errorResponsePayload.data(using: .utf8)),
+            statusCode: HttpStatusCode.ok
+        )
+    }
+
+    public func execute(request: SdkHttpRequest) async throws -> HttpResponse {
+        return successHttpResponse(request: request)
+    }
+}
+
+class S3ErrorIn200Test: XCTestCase {
+
+    override class func setUp() {
+        AwsCommonRuntimeKit.CommonRuntimeKit.initialize()
+    }
+
+    /// S3Client throws expected error in response (200) with <Error> tag
+    func test_foundExpectedError() async throws {
+        let config = try await S3Client.S3ClientConfiguration(region: "us-west-2")
+        config.httpClientEngine = MockHttpClientEngine()
+        let client = S3Client(config: config)
+
+        do {
+            // any method on S3Client where the output shape doesnt have a stream
+            _ = try await client.listBuckets(input: .init())
+            XCTFail("Expected an error to be thrown, but it was not.")
+        } catch let error as UnknownAWSHTTPServiceError {
+            // check for the error we added in our mock client
+            XCTAssertEqual("Please reduce your request rate.", error.message)
+        } catch {
+            XCTFail("Unexpected error: \(error)")
+        }
+    }
+}

Sources/Core/AWSClientRuntime/Middlewares/AWSS3ErrorWith200StatusXMLMiddleware.swift

@@ -0,0 +1,50 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import ClientRuntime
+
+public struct AWSS3ErrorWith200StatusXMLMiddleware<OperationStackOutput>: Middleware {
+    public let id: String = "AWSS3ErrorWith200StatusXMLMiddleware"
+
+    public init() {}
+
+    public func handle<H>(context: Context,
+                          input: SdkHttpRequest,
+                          next: H) async throws -> OperationOutput<OperationStackOutput>
+    where H: Handler,
+          Self.MInput == H.Input,
+          Self.MOutput == H.Output,
+          Self.Context == H.Context {
+
+        // Let the next handler in the chain process the input
+        let response = try await next.handle(context: context, input: input)
+
+        // Check if the status code is OK (200)
+        guard response.httpResponse.statusCode == .ok else {
+            return response
+        }
+
+        // Check if the response body contains an XML Error
+        guard let data = try await response.httpResponse.body.readData() else {
+            return response
+        }
+
+        let xmlString = String(data: data, encoding: .utf8) ?? ""
+        if xmlString.contains("<Error>") {
+            // Handle the error as a 500 Internal Server Error
+            var modifiedResponse = response
+            modifiedResponse.httpResponse.statusCode = .internalServerError
+            return modifiedResponse
+        }
+
+        return response
+    }
+
+    public typealias MInput = SdkHttpRequest
+    public typealias MOutput = OperationOutput<OperationStackOutput>
+    public typealias Context = HttpContext
+}