Enhance StreamHandle API by adding get_read_error() and has_read_error() methods for improved error handling

Author: yhirose

README-stream.md

@@ -107,8 +107,9 @@ if (handle.is_valid()) {
 | `response` | `std::unique_ptr<Response>` | HTTP response with headers |
 | `error` | `Error` | Error code if request failed |
 | `is_valid()` | `bool` | Returns true if response is valid |
-| `is_socket_direct_mode()` | `bool` | Returns true (always direct socket reading) |
 | `read(buf, len)` | `ssize_t` | Read up to `len` bytes directly from socket |
+| `get_read_error()` | `Error` | Get the last read error |
+| `has_read_error()` | `bool` | Check if a read error occurred |
 
 ### High-Level API: `stream::Get()` and `stream::Result`
 

httplib.h

@@ -1496,28 +1496,12 @@ class ClientImpl {
 
   // Streaming handle for reading response body incrementally
   struct StreamHandle {
-    // Common fields
+    // Public fields
     std::unique_ptr<Response> response;
     Error error = Error::Success;
 
-    // Mode 1: Memory buffer (existing behavior)
-    size_t read_offset_ = 0;
-
-    // Mode 2: Socket direct (true streaming)
-    std::unique_ptr<ClientConnection> connection_; // Socket ownership
-    std::unique_ptr<Stream> socket_stream_;        // SocketStream ownership
-    Stream *stream_ = nullptr;                     // Stream for reading
-    detail::BodyReader body_reader_;               // Body reading state
-
-    // Compression support
-    std::unique_ptr<detail::decompressor> decompressor_;
-    std::string decompress_buffer_; // Buffer for decompressed data
-    size_t decompress_offset_ = 0;  // Read position in decompress_buffer_
-
-    // Default constructor
+    // Constructors and assignment operators
     StreamHandle() = default;
-
-    // Move-only semantics (non-copyable due to unique_ptr members)
     StreamHandle(const StreamHandle &) = delete;
     StreamHandle &operator=(const StreamHandle &) = delete;
     StreamHandle(StreamHandle &&) = default;
@@ -1526,30 +1510,39 @@ class ClientImpl {
     // Destructor: Cleans up socket connection.
     // In socket direct mode, if the body was not fully read, remaining data
     // is discarded and the connection is closed (cannot be reused).
-    // This is safe but may leave unread data in the socket buffer.
     ~StreamHandle() = default;
 
+    // Check if the handle is valid
     bool is_valid() const {
       return response != nullptr && error == Error::Success;
     }
 
-    // Check if using socket direct mode (true streaming)
-    bool is_socket_direct_mode() const { return stream_ != nullptr; }
-
     // Read up to len bytes into buf, returns number of bytes read (0 at EOF)
     // Implementation is below decompressor class definition
     ssize_t read(char *buf, size_t len);
 
-  private:
-    // Read with decompression support (implemented after decompressor class)
-    ssize_t read_with_decompression(char *buf, size_t len);
-
-  public:
     // Get the last error that occurred during reading (socket direct mode only)
     Error get_read_error() const { return body_reader_.last_error; }
 
     // Check if a read error occurred (socket direct mode only)
     bool has_read_error() const { return body_reader_.has_error(); }
+
+  private:
+    friend class ClientImpl;
+
+    // Read with decompression support (implemented after decompressor class)
+    ssize_t read_with_decompression(char *buf, size_t len);
+
+    // Socket connection ownership
+    std::unique_ptr<ClientConnection> connection_; // Socket ownership
+    std::unique_ptr<Stream> socket_stream_;        // SocketStream ownership
+    Stream *stream_ = nullptr;                     // Stream for reading
+    detail::BodyReader body_reader_;               // Body reading state
+
+    // Compression support
+    std::unique_ptr<detail::decompressor> decompressor_;
+    std::string decompress_buffer_; // Buffer for decompressed data
+    size_t decompress_offset_ = 0;  // Read position in decompress_buffer_
   };
 
   // clang-format off
@@ -2923,21 +2916,8 @@ inline bool is_field_value(const std::string &s) { return is_field_content(s); }
 inline ssize_t ClientImpl::StreamHandle::read(char *buf, size_t len) {
   if (!is_valid() || !response) { return -1; }
 
-  if (is_socket_direct_mode()) {
-    // Socket direct mode: read from stream via BodyReader
-    if (decompressor_) { return read_with_decompression(buf, len); }
-    return body_reader_.read(buf, len);
-  } else {
-    // Memory buffer mode: read from pre-loaded response body
-    const auto &body = response->body;
-    if (read_offset_ >= body.size()) { return 0; }
-
-    auto remaining = body.size() - read_offset_;
-    auto to_read = (std::min)(len, remaining);
-    std::memcpy(buf, body.data() + read_offset_, to_read);
-    read_offset_ += to_read;
-    return static_cast<ssize_t>(to_read);
-  }
+  if (decompressor_) { return read_with_decompression(buf, len); }
+  return body_reader_.read(buf, len);
 }
 
 inline ssize_t ClientImpl::StreamHandle::read_with_decompression(char *buf,