Add detection of pipelined requests in handle_client_read by checking if buffered data starts with a new HTTP request. When a pipelined request is detected, the server now sends a 400 Bad Request response with a descriptive body, closes the upstream connection, and transitions the client state to CLIENT_STATE_CLOSING. Previously, the server would silently close the upstream connection and continue reading headers. The change also includes a comprehensive test that validates the rejection behavior, response content, and connection state transitions for pipelined requests.
Add logic in connection_close to detect remaining buffered data on client read buffer when an upstream connection is closed, and invoke handle_client_read to process it. Also add a forward declaration for handle_client_read and include debug logging for routing decisions. A new test validates that pipelined requests buffered before upstream close are correctly handled.
Reset multiple connection flags (content_type_checked, is_textual_content, response_headers_parsed, original_content_length, content_length_delta, patch_blocked) when reusing connection for internal route keep-alive. Add immediate handling of any buffered read data after state reset to prevent stale data blocking subsequent requests. Add comprehensive test verifying second request processing on internal dashboard route via Unix socket pair.
Add real-time tracking of accepted connections, upstream connection success/failure, DNS errors, and retries to connection.c. Introduce histogram, rate tracker, and health score data structures in types.h and monitor.h/c. Redesign dashboard HTML/CSS with color-coded health metrics, responsive charts grid, and tall chart containers for improved visualization of system performance data.
