[#142] Consolidate discovery handlers into unified class

src/ros2_medkit_gateway/CMakeLists.txt

@@ -130,13 +130,12 @@ add_library(gateway_lib STATIC
   # HTTP module (subfolder)
   src/http/http_server.cpp
   src/http/rest_server.cpp
-  # HTTP handlers - discovery
-  src/http/handlers/discovery/area_handlers.cpp
-  src/http/handlers/discovery/component_handlers.cpp
-  src/http/handlers/discovery/app_handlers.cpp
-  src/http/handlers/discovery/function_handlers.cpp
+  # HTTP handlers - discovery (unified)
+  src/http/handlers/discovery_handlers.cpp
   # HTTP handlers - utilities
   src/http/handlers/capability_builder.cpp
+  # HTTP handlers - resource handlers (unified across entity types)
+  src/http/handlers/data_handlers.cpp
   # HTTP handlers - other
   src/http/handlers/handler_context.cpp
   src/http/handlers/health_handlers.cpp

src/ros2_medkit_gateway/include/ros2_medkit_gateway/http/handlers/data_handlers.hpp

@@ -0,0 +1,102 @@
+// Copyright 2026 bburda
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <httplib.h>
+
+#include "ros2_medkit_gateway/http/handlers/handler_context.hpp"
+
+namespace ros2_medkit_gateway {
+namespace handlers {
+
+/**
+ * @brief Unified HTTP handlers for data operations across all SOVD entity types
+ *
+ * This class provides entity-agnostic handlers for /data endpoints.
+ * Works for: /areas/{id}/data, /components/{id}/data, /apps/{id}/data, /functions/{id}/data
+ *
+ * Key design decisions:
+ * - Single handler implementation shared across all entity types
+ * - Entity type resolved from URL regex match or inferred from entity ID
+ * - Data aggregated from entity hierarchy (e.g., component includes apps' topics)
+ */
+class DataHandlers {
+ public:
+  explicit DataHandlers(HandlerContext & ctx) : ctx_(ctx) {
+  }
+
+  /**
+   * @brief List all data items (topics) for an entity
+   *
+   * GET /{entities}/{id}/data
+   *
+   * URL matches:
+   * - matches[1]: entity_id
+   *
+   * Returns SOVD ValueMetadata items with x-medkit ROS2-specific extensions.
+   */
+  void handle_list_data(const httplib::Request & req, httplib::Response & res);
+
+  /**
+   * @brief Get a single data item (topic value) for an entity
+   *
+   * GET /{entities}/{id}/data/{topic}
+   *
+   * URL matches:
+   * - matches[1]: entity_id
+   * - matches[2]: topic_id (may be URL-encoded with slashes)
+   *
+   * Returns SOVD ReadValue with current topic data and type_info schema.
+   */
+  void handle_get_data_item(const httplib::Request & req, httplib::Response & res);
+
+  /**
+   * @brief Write data to a topic (publish)
+   *
+   * PUT /{entities}/{id}/data/{topic}
+   *
+   * URL matches:
+   * - matches[1]: entity_id
+   * - matches[2]: topic_id (may be URL-encoded with slashes)
+   *
+   * Request body: { "type": "pkg/msg/Type", "data": {...} }
+   * Returns SOVD WriteValue with echoed data.
+   */
+  void handle_put_data_item(const httplib::Request & req, httplib::Response & res);
+
+  /**
+   * @brief List data categories (not implemented for ROS 2)
+   *
+   * GET /{entities}/{id}/data-categories
+   *
+   * Returns 501 Not Implemented.
+   */
+  void handle_data_categories(const httplib::Request & req, httplib::Response & res);
+
+  /**
+   * @brief List data groups (not implemented for ROS 2)
+   *
+   * GET /{entities}/{id}/data-groups
+   *
+   * Returns 501 Not Implemented.
+   */
+  void handle_data_groups(const httplib::Request & req, httplib::Response & res);
+
+ private:
+  HandlerContext & ctx_;
+};
+
+}  // namespace handlers
+}  // namespace ros2_medkit_gateway