Refactor AWS Chunked logic from HTTP clients

src/aws-cpp-sdk-core/include/aws/core/client/ClientConfiguration.h

@@ -78,6 +78,16 @@ namespace Aws
           WHEN_REQUIRED,
         };
 
+        /**
+         * Control HTTP client chunking implementation mode.
+         * DEFAULT: Use SDK's ChunkingInterceptor for aws-chunked encoding
+         * CLIENT_IMPLEMENTATION: Rely on HTTP client's native chunking (default for custom clients)
+         */
+        enum class HttpClientChunkedMode {
+          DEFAULT,
+          CLIENT_IMPLEMENTATION,
+        };
+
         struct RequestCompressionConfig {
           UseRequestCompression useRequestCompression=UseRequestCompression::ENABLE;
           size_t requestMinCompressionSizeBytes = 10240;
@@ -493,6 +503,12 @@ namespace Aws
            * https://docs.aws.amazon.com/sdkref/latest/guide/feature-account-endpoints.html
            */
           Aws::String accountIdEndpointMode = "preferred";
+
+          /**
+           * Control HTTP client chunking implementation mode.
+           * Default is set automatically: CLIENT_IMPLEMENTATION for custom clients, DEFAULT for AWS clients.
+           */
+          HttpClientChunkedMode httpClientChunkedMode = HttpClientChunkedMode::CLIENT_IMPLEMENTATION;
           /**
           * Configuration structure for credential providers in the AWS SDK.
           * This structure allows passing configuration options to credential providers

src/aws-cpp-sdk-core/include/aws/core/http/HttpClient.h

@@ -48,6 +48,11 @@ namespace Aws
              */
             virtual bool SupportsChunkedTransferEncoding() const { return true; }
 
+            /**
+             * Returns true if this is a default AWS SDK HTTP client implementation.
+             */
+            virtual bool IsDefaultAwsHttpClient() const { return false; }
+
             /**
              * Stops all requests in progress and prevents any others from initiating.
              */

src/aws-cpp-sdk-core/include/aws/core/http/crt/CRTHttpClient.h

@@ -52,6 +52,8 @@ namespace Aws
                 Aws::Utils::RateLimits::RateLimiterInterface* readLimiter,
                 Aws::Utils::RateLimits::RateLimiterInterface* writeLimiter) const override;
 
+            bool IsDefaultAwsHttpClient() const override { return true; }
+
         private:
             // Yeah, I know, but someone made MakeRequest() const and didn't think about the fact that
             // making an HTTP request most certainly mutates state. It was me. I'm the person that did that, and

src/aws-cpp-sdk-core/include/aws/core/http/curl/CurlHttpClient.h

@@ -37,6 +37,8 @@ class AWS_CORE_API CurlHttpClient: public HttpClient
         Aws::Utils::RateLimits::RateLimiterInterface* readLimiter = nullptr,
         Aws::Utils::RateLimits::RateLimiterInterface* writeLimiter = nullptr) const override;
 
+    bool IsDefaultAwsHttpClient() const override { return true; }
+
     static void InitGlobalState();
     static void CleanupGlobalState();
 

src/aws-cpp-sdk-core/include/aws/core/http/windows/IXmlHttpRequest2HttpClient.h

@@ -54,6 +54,8 @@ namespace Aws
              */
             virtual bool SupportsChunkedTransferEncoding() const override { return false; }
 
+            bool IsDefaultAwsHttpClient() const override { return true; }
+
         protected:
             /**
              * Override any configuration on request handle.

src/aws-cpp-sdk-core/include/aws/core/http/windows/WinHttpSyncHttpClient.h

@@ -42,6 +42,8 @@ namespace Aws
              */
             const char* GetLogTag() const override { return "WinHttpSyncHttpClient"; }
 
+            bool IsDefaultAwsHttpClient() const override { return true; }
+
         private:
             // WinHttp specific implementations
             void* OpenRequest(const std::shared_ptr<HttpRequest>& request, void* connection, const Aws::StringStream& ss) const override;

src/aws-cpp-sdk-core/include/aws/core/http/windows/WinINetSyncHttpClient.h

@@ -39,6 +39,8 @@ namespace Aws
              * Gets log tag for use in logging in the base class.
              */
             const char* GetLogTag() const override { return "WinInetSyncHttpClient"; }
+
+            bool IsDefaultAwsHttpClient() const override { return true; }
         private:
 
             // WinHttp specific implementations

src/aws-cpp-sdk-core/include/smithy/client/AwsSmithyClientBase.h

@@ -9,6 +9,7 @@
 #include <smithy/tracing/TelemetryProvider.h>
 #include <smithy/interceptor/Interceptor.h>
 #include <smithy/client/features/ChecksumInterceptor.h>
+#include <smithy/client/features/ChunkingInterceptor.h>
 #include <smithy/client/features/UserAgentInterceptor.h>
 
 #include <aws/crt/Variant.h>
@@ -20,6 +21,7 @@
 #include <aws/core/utils/Outcome.h>
 #include <aws/core/NoResult.h>
 #include <aws/core/http/HttpClientFactory.h>
+#include <aws/core/http/HttpClient.h>
 #include <aws/core/client/AWSErrorMarshaller.h>
 #include <aws/core/AmazonWebServiceResult.h>
 #include <utility>
@@ -99,8 +101,13 @@ namespace client
           m_serviceUserAgentName(std::move(serviceUserAgentName)),
           m_httpClient(std::move(httpClient)),
           m_errorMarshaller(std::move(errorMarshaller)),
-          m_interceptors{Aws::MakeShared<ChecksumInterceptor>("AwsSmithyClientBase", *m_clientConfig)}
+          m_interceptors({
+              Aws::MakeShared<ChecksumInterceptor>("AwsSmithyClientBase", *m_clientConfig),
+              Aws::MakeShared<features::ChunkingInterceptor>("AwsSmithyClientBase", 
+                  m_httpClient->IsDefaultAwsHttpClient() ? Aws::Client::HttpClientChunkedMode::DEFAULT : m_clientConfig->httpClientChunkedMode)
+          })
         {
+
             baseInit();
         }
 

src/aws-cpp-sdk-core/include/smithy/client/features/ChunkingInterceptor.h

@@ -0,0 +1,232 @@
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+#pragma once
+#include <aws/core/http/HttpRequest.h>
+#include <aws/core/utils/Array.h>
+#include <aws/core/utils/StringUtils.h>
+#include <aws/core/utils/HashingUtils.h>
+#include <aws/core/utils/logging/LogMacros.h>
+#include <aws/core/utils/memory/stl/AWSStringStream.h>
+#include <aws/core/utils/memory/stl/AWSVector.h>
+#include <smithy/interceptor/Interceptor.h>
+#include <aws/core/client/ClientConfiguration.h>
+#include <aws/core/utils/Outcome.h>
+#include <aws/core/client/AWSError.h>
+#include <memory>
+
+namespace smithy {
+namespace client {
+namespace features {
+
+static const size_t AWS_DATA_BUFFER_SIZE = 65536;
+static const char* ALLOCATION_TAG = "ChunkingInterceptor";
+static const char* CHECKSUM_HEADER_PREFIX = "x-amz-checksum-";
+
+template <size_t DataBufferSize = AWS_DATA_BUFFER_SIZE>
+class AwsChunkedStreamBuf : public std::streambuf {
+public:
+    AwsChunkedStreamBuf(Aws::Http::HttpRequest* request,
+                        const std::shared_ptr<Aws::IOStream>& stream,
+                        size_t bufferSize = DataBufferSize)
+        : m_request(request),
+          m_stream(stream),
+          m_data(bufferSize)
+    {
+        assert(m_stream != nullptr);
+        if (m_stream == nullptr) {
+            AWS_LOGSTREAM_ERROR("AwsChunkedStream", "stream is null");
+        }
+        assert(m_request != nullptr);
+        if (m_request == nullptr) {
+            AWS_LOGSTREAM_ERROR("AwsChunkedStream", "request is null");
+        }
+    }
+
+protected:
+    int_type underflow() override {
+        if (gptr() && gptr() < egptr()) {
+            return traits_type::to_int_type(*gptr());
+        }
+
+        // Compact buffer when consumed data exceeds half buffer size
+        if (m_chunkingBufferPos > m_chunkingBuffer.GetLength() / 2) {
+            size_t remaining = m_chunkingBufferSize - m_chunkingBufferPos;
+            if (remaining > 0) {
+                std::memmove(m_chunkingBuffer.GetUnderlyingData(), 
+                           m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferPos, 
+                           remaining);
+            }
+            m_chunkingBufferSize = remaining;
+            m_chunkingBufferPos = 0;
+        }
+
+        // only read and write to chunked stream if the underlying stream
+        // is still in a valid state and we have buffer space
+        if (m_stream->good()) {
+            // Check if we have enough space for worst-case chunk (data + header + footer)
+            size_t maxChunkSize = m_data.GetLength() + 20; // data + hex header + CRLF
+            if (m_chunkingBufferSize + maxChunkSize <= m_chunkingBuffer.GetLength()) {
+                // Try to read in a 64K chunk, if we cant we know the stream is over
+                m_stream->read(m_data.GetUnderlyingData(), m_data.GetLength());
+                size_t bytesRead = static_cast<size_t>(m_stream->gcount());
+                writeChunk(bytesRead);
+
+                // if we've read everything from the stream, we want to add the trailer
+                // to the underlying stream
+                if ((m_stream->peek() == EOF || m_stream->eof()) && !m_stream->bad()) {
+                    writeTrailerToUnderlyingStream();
+                }
+            }
+        }
+
+        // if the chunking buffer is empty there is nothing to read
+        if (m_chunkingBufferPos >= m_chunkingBufferSize) {
+            return traits_type::eof();
+        }
+
+        // Set up buffer pointers to read from chunking buffer
+        size_t remainingBytes = m_chunkingBufferSize - m_chunkingBufferPos;
+        size_t bytesToRead = std::min(remainingBytes, DataBufferSize);
+
+        setg(m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferPos, 
+             m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferPos, 
+             m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferPos + bytesToRead);
+
+        m_chunkingBufferPos += bytesToRead;
+
+        return traits_type::to_int_type(*gptr());
+    }
+
+private:
+    void writeTrailerToUnderlyingStream() {
+        Aws::String trailer = "0\r\n";
+        if (m_request->GetRequestHash().second != nullptr) {
+            trailer += "x-amz-checksum-" + m_request->GetRequestHash().first + ":"
+                     + Aws::Utils::HashingUtils::Base64Encode(m_request->GetRequestHash().second->GetHash().GetResult()) + "\r\n";
+        }
+        trailer += "\r\n";
+        if (m_chunkingBufferSize + trailer.length() <= m_chunkingBuffer.GetLength()) {
+            std::memcpy(m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferSize, trailer.c_str(), trailer.length());
+            m_chunkingBufferSize += trailer.length();
+        }
+    }
+
+    void writeChunk(size_t bytesRead) {
+        if (m_request->GetRequestHash().second != nullptr) {
+            m_request->GetRequestHash().second->Update(reinterpret_cast<unsigned char*>(m_data.GetUnderlyingData()), bytesRead);
+        }
+
+        if (bytesRead > 0) {
+            Aws::String chunkHeader = Aws::Utils::StringUtils::ToHexString(bytesRead) + "\r\n";
+            size_t totalSize = chunkHeader.length() + bytesRead + 2;
+            if (m_chunkingBufferSize + totalSize <= m_chunkingBuffer.GetLength()) {
+                std::memcpy(m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferSize, chunkHeader.c_str(), chunkHeader.length());
+                m_chunkingBufferSize += chunkHeader.length();
+                std::memcpy(m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferSize, m_data.GetUnderlyingData(), bytesRead);
+                m_chunkingBufferSize += bytesRead;
+                std::memcpy(m_chunkingBuffer.GetUnderlyingData() + m_chunkingBufferSize, "\r\n", 2);
+                m_chunkingBufferSize += 2;
+            }
+        }
+    }
+
+    Aws::Utils::Array<char> m_chunkingBuffer{DataBufferSize * 4};
+    size_t m_chunkingBufferSize{0};
+    size_t m_chunkingBufferPos{0};
+    Aws::Http::HttpRequest* m_request{nullptr};
+    std::shared_ptr<Aws::IOStream> m_stream;
+    Aws::Utils::Array<char> m_data;
+};
+
+class AwsChunkedIOStream : public Aws::IOStream {
+public:
+    AwsChunkedIOStream(Aws::Http::HttpRequest* request,
+                       const std::shared_ptr<Aws::IOStream>& originalBody,
+                       size_t bufferSize = AWS_DATA_BUFFER_SIZE)
+        : Aws::IOStream(&m_buf),
+          m_buf(request, originalBody, bufferSize) {}
+
+private:
+    AwsChunkedStreamBuf<> m_buf;
+};
+
+/**
+ * Interceptor that handles chunked encoding for streaming requests with checksums.
+ * Wraps request body with chunked stream and sets appropriate headers.
+ */
+class ChunkingInterceptor : public smithy::interceptor::Interceptor {
+public:
+    explicit ChunkingInterceptor(Aws::Client::HttpClientChunkedMode httpClientChunkedMode)
+        : m_httpClientChunkedMode(httpClientChunkedMode) {}
+    ~ChunkingInterceptor() override = default;
+
+    ModifyRequestOutcome ModifyBeforeSigning(smithy::interceptor::InterceptorContext& context) override {
+        auto request = context.GetTransmitRequest();
+
+        if (!ShouldApplyChunking(request)) {
+            return request;
+        }
+
+        auto originalBody = request->GetContentBody();
+        if (!originalBody) {
+            return request;
+        }
+
+        // Set up chunked encoding headers for checksum calculation
+        const auto& hashPair = request->GetRequestHash();
+        if (hashPair.second != nullptr) {
+            Aws::String checksumHeaderValue = Aws::String(CHECKSUM_HEADER_PREFIX) + hashPair.first;
+            request->DeleteHeader(checksumHeaderValue.c_str());
+            request->SetHeaderValue(Aws::Http::AWS_TRAILER_HEADER, checksumHeaderValue);
+            request->SetTransferEncoding(Aws::Http::CHUNKED_VALUE);
+
+            if (!request->HasContentEncoding()) {
+                request->SetContentEncoding(Aws::Http::AWS_CHUNKED_VALUE);
+            } else {
+                Aws::String currentEncoding = request->GetContentEncoding();
+                if (currentEncoding.find(Aws::Http::AWS_CHUNKED_VALUE) == Aws::String::npos) {
+                    request->SetContentEncoding(Aws::String{Aws::Http::AWS_CHUNKED_VALUE} + "," + currentEncoding);
+                }
+            }
+
+            if (request->HasHeader(Aws::Http::CONTENT_LENGTH_HEADER)) {
+                request->SetHeaderValue(Aws::Http::DECODED_CONTENT_LENGTH_HEADER, request->GetHeaderValue(Aws::Http::CONTENT_LENGTH_HEADER));
+                request->DeleteHeader(Aws::Http::CONTENT_LENGTH_HEADER);
+            }
+        }
+
+        auto chunkedBody = Aws::MakeShared<AwsChunkedIOStream>(
+            ALLOCATION_TAG, request.get(), originalBody);
+
+        request->AddContentBody(chunkedBody);
+        return request;
+    }
+
+    ModifyResponseOutcome ModifyBeforeDeserialization(smithy::interceptor::InterceptorContext& context) override {
+        return context.GetTransmitResponse();
+    }
+
+private:
+    bool ShouldApplyChunking(const std::shared_ptr<Aws::Http::HttpRequest>& request) const {
+        // Use configuration setting to determine chunking behavior
+        if (m_httpClientChunkedMode != Aws::Client::HttpClientChunkedMode::DEFAULT) {
+            return false;
+        }
+
+        if (!request || !request->GetContentBody()) {
+            return false;
+        }
+
+        // Check if request has checksum requirements
+        const auto& hashPair = request->GetRequestHash();
+        return hashPair.second != nullptr;
+    }
+
+    Aws::Client::HttpClientChunkedMode m_httpClientChunkedMode;
+};
+
+} // namespace features
+} // namespace client
+} // namespace smithy

src/aws-cpp-sdk-core/source/auth/signer/AWSAuthV4Signer.cpp

@@ -218,26 +218,10 @@ bool AWSAuthV4Signer::SignRequestWithCreds(Aws::Http::HttpRequest& request, cons
         request.SetAwsSessionToken(credentials.GetSessionToken());
     }
 
-    // If the request checksum, set the signer to use a unsigned
-    // trailing payload. otherwise use it in the header
-    if (request.GetRequestHash().second != nullptr && !request.GetRequestHash().first.empty() && request.GetContentBody() != nullptr) {
-      AWS_LOGSTREAM_DEBUG(v4LogTag, "Note: Http payloads are not being signed. signPayloads="
-                                        << signBody << " http scheme=" << Http::SchemeMapper::ToString(request.GetUri().GetScheme()));
-      if (request.GetRequestHash().second != nullptr) {
+    // If the request has checksum and chunking was applied by interceptor, use streaming payload
+    if (request.GetRequestHash().second != nullptr && !request.GetRequestHash().first.empty() && 
+        request.GetContentBody() != nullptr && request.HasHeader(Http::AWS_TRAILER_HEADER)) {
         payloadHash = STREAMING_UNSIGNED_PAYLOAD_TRAILER;
-        Aws::String checksumHeaderValue = Aws::String("x-amz-checksum-") + request.GetRequestHash().first;
-        request.DeleteHeader(checksumHeaderValue.c_str());
-        request.SetHeaderValue(Http::AWS_TRAILER_HEADER, checksumHeaderValue);
-        request.SetTransferEncoding(CHUNKED_VALUE);
-        request.HasContentEncoding()
-                ? request.SetContentEncoding(Aws::String{Http::AWS_CHUNKED_VALUE} + "," + request.GetContentEncoding())
-                : request.SetContentEncoding(Http::AWS_CHUNKED_VALUE);
-
-        if (request.HasHeader(Http::CONTENT_LENGTH_HEADER)) {
-          request.SetHeaderValue(Http::DECODED_CONTENT_LENGTH_HEADER, request.GetHeaderValue(Http::CONTENT_LENGTH_HEADER));
-          request.DeleteHeader(Http::CONTENT_LENGTH_HEADER);
-        }
-      }
     } else {
       payloadHash = ComputePayloadHash(request);
       if (payloadHash.empty()) {