Implement ws-protocol's fetchAsset specification (#232)

### Public-Facing Changes

- Implements foxglove/ws-protocol#462 to allow
fetching of assets

### Description
Implements the above mentioned spec to fetch assets which will allow
Foxglove Studio to request assets (such as URDF mesh files) over the
websocket connection.

.vscode/c_cpp_properties.json

@@ -17,7 +17,6 @@
           "/usr/include"
         ]
       },
-      "defines": ["ASIO_STANDALONE"],
       "cppStandard": "c++17"
     }
   ],

CMakeLists.txt

@@ -13,6 +13,7 @@ project(foxglove_bridge LANGUAGES CXX VERSION 0.6.4)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+add_definitions(-DASIO_STANDALONE)
 
 macro(enable_strict_compiler_warnings target)
   if (MSVC)
@@ -93,13 +94,13 @@ if("$ENV{ROS_VERSION}" STREQUAL "1")
     message(STATUS "Building with catkin")
     set(ROS_BUILD_TYPE "catkin")
 
-    find_package(catkin REQUIRED COMPONENTS nodelet ros_babel_fish rosgraph_msgs roslib roscpp)
+    find_package(catkin REQUIRED COMPONENTS nodelet resource_retriever ros_babel_fish rosgraph_msgs roslib roscpp)
     find_package(Boost REQUIRED)
 
     catkin_package(
       INCLUDE_DIRS foxglove_bridge_base/include
       LIBRARIES foxglove_bridge_base foxglove_bridge_nodelet
-      CATKIN_DEPENDS nodelet ros_babel_fish rosgraph_msgs roslib roscpp
+      CATKIN_DEPENDS nodelet resource_retriever ros_babel_fish rosgraph_msgs roslib roscpp
       DEPENDS Boost
     )
 
@@ -135,6 +136,7 @@ elseif("$ENV{ROS_VERSION}" STREQUAL "2")
     find_package(rosgraph_msgs REQUIRED)
     find_package(rclcpp REQUIRED)
     find_package(rclcpp_components REQUIRED)
+    find_package(resource_retriever REQUIRED)
 
     add_library(foxglove_bridge_component SHARED
       ros2_foxglove_bridge/src/message_definition_cache.cpp
@@ -149,7 +151,7 @@ elseif("$ENV{ROS_VERSION}" STREQUAL "2")
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/ros2_foxglove_bridge/include>
         $<INSTALL_INTERFACE:include>
     )
-    ament_target_dependencies(foxglove_bridge_component rclcpp rclcpp_components rosgraph_msgs)
+    ament_target_dependencies(foxglove_bridge_component rclcpp rclcpp_components resource_retriever rosgraph_msgs)
     target_link_libraries(foxglove_bridge_component foxglove_bridge_base)
     rclcpp_components_register_nodes(foxglove_bridge_component "foxglove_bridge::FoxgloveBridge")
     enable_strict_compiler_warnings(foxglove_bridge_component)
@@ -258,6 +260,9 @@ elseif(ROS_BUILD_TYPE STREQUAL "ament_cmake")
     install(DIRECTORY ros2_foxglove_bridge/launch/
       DESTINATION share/${PROJECT_NAME}/
     )
+    install(FILES ros2_foxglove_bridge/include/foxglove_bridge/utils.hpp
+      DESTINATION include/${PROJECT_NAME}/
+    )
     ament_export_libraries(foxglove_bridge_base foxglove_bridge_component)
     ament_package()
 endif()

README.md

@@ -76,7 +76,8 @@ Parameters are provided to configure the behavior of the bridge. These parameter
   * __client_topic_whitelist__: List of regular expressions ([ECMAScript grammar](https://en.cppreference.com/w/cpp/regex/ecmascript)) of whitelisted client-published topic names. Defaults to `[".*"]`.
  * __send_buffer_limit__: Connection send buffer limit in bytes. Messages will be dropped when a connection's send buffer reaches this limit to avoid a queue of outdated messages building up. Defaults to `10000000` (10 MB).
  * __use_compression__: Use websocket compression (permessage-deflate). Suited for connections with smaller bandwith, at the cost of additional CPU load.
- * __capabilities__: List of supported [server capabilities](https://github.com/foxglove/ws-protocol/blob/main/docs/spec.md). Defaults to `[clientPublish,parameters,parametersSubscribe,services,connectionGraph]`.
+ * __capabilities__: List of supported [server capabilities](https://github.com/foxglove/ws-protocol/blob/main/docs/spec.md). Defaults to `[clientPublish,parameters,parametersSubscribe,services,connectionGraph,assets]`.
+ * __asset_uri_allowlist__: List of regular expressions ([ECMAScript grammar](https://en.cppreference.com/w/cpp/regex/ecmascript)) of allowed asset URIs. Uses the [resource_retriever](https://index.ros.org/p/resource_retriever/github-ros-resource_retriever) to resolve `package://`, `file://` or `http(s)://` URIs. Note that this list should be carefully configured such that no confidential files are accidentally exposed over the websocket connection. As an extra security measure, URIs containing two consecutive dots (`..`) are disallowed as they could be used to construct URIs that would allow retrieval of confidential files if the allowlist is not configured strict enough (e.g. `package://<pkg_name>/../../../secret.txt`). Defaults to `["package://(\w+/?)+\.(dae|stl|urdf|xacro)"]`.
  * (ROS 1) __max_update_ms__: The maximum number of milliseconds to wait in between polling `roscore` for new topics, services, or parameters. Defaults to `5000`.
  * (ROS 2) __num_threads__: The number of threads to use for the ROS node executor. This controls the number of subscriptions that can be processed in parallel. 0 means one thread per CPU core. Defaults to `0`.
  * (ROS 2) __min_qos_depth__: Minimum depth used for the QoS profile of subscriptions. Defaults to `1`. This is to set a lower limit for a subscriber's QoS depth which is computed by summing up depths of all publishers. See also [#208](https://github.com/foxglove/ros-foxglove-bridge/issues/208).

foxglove_bridge_base/include/foxglove_bridge/common.hpp

@@ -16,10 +16,11 @@ constexpr char CAPABILITY_PARAMETERS[] = "parameters";
 constexpr char CAPABILITY_PARAMETERS_SUBSCRIBE[] = "parametersSubscribe";
 constexpr char CAPABILITY_SERVICES[] = "services";
 constexpr char CAPABILITY_CONNECTION_GRAPH[] = "connectionGraph";
+constexpr char CAPABILITY_ASSETS[] = "assets";
 
-constexpr std::array<const char*, 5> DEFAULT_CAPABILITIES = {
+constexpr std::array<const char*, 6> DEFAULT_CAPABILITIES = {
   CAPABILITY_CLIENT_PUBLISH, CAPABILITY_CONNECTION_GRAPH, CAPABILITY_PARAMETERS_SUBSCRIBE,
-  CAPABILITY_PARAMETERS,     CAPABILITY_SERVICES,
+  CAPABILITY_PARAMETERS,     CAPABILITY_SERVICES,         CAPABILITY_ASSETS,
 };
 
 using ChannelId = uint32_t;
@@ -31,6 +32,7 @@ enum class BinaryOpcode : uint8_t {
   MESSAGE_DATA = 1,
   TIME_DATA = 2,
   SERVICE_CALL_RESPONSE = 3,
+  FETCH_ASSET_RESPONSE = 4,
 };
 
 enum class ClientBinaryOpcode : uint8_t {
@@ -145,4 +147,16 @@ struct ServiceResponse {
 
 using ServiceRequest = ServiceResponse;
 
+enum class FetchAssetStatus : uint8_t {
+  Success = 0,
+  Error = 1,
+};
+
+struct FetchAssetResponse {
+  uint32_t requestId;
+  FetchAssetStatus status;
+  std::string errorMessage;
+  std::vector<uint8_t> data;
+};
+
 }  // namespace foxglove

foxglove_bridge_base/include/foxglove_bridge/server_interface.hpp

@@ -73,6 +73,7 @@ struct ServerHandlers {
     parameterSubscriptionHandler;
   std::function<void(const ServiceRequest&, ConnectionHandle)> serviceRequestHandler;
   std::function<void(bool)> subscribeConnectionGraphHandler;
+  std::function<void(const std::string&, uint32_t, ConnectionHandle)> fetchAssetHandler;
 };
 
 template <typename ConnectionHandle>
@@ -101,6 +102,8 @@ class ServerInterface {
   virtual void updateConnectionGraph(const MapOfSets& publishedTopics,
                                      const MapOfSets& subscribedTopics,
                                      const MapOfSets& advertisedServices) = 0;
+  virtual void sendFetchAssetResponse(ConnectionHandle clientHandle,
+                                      const FetchAssetResponse& response) = 0;
 
   virtual uint16_t getPort() = 0;
   virtual std::string remoteEndpointString(ConnectionHandle clientHandle) = 0;

foxglove_bridge_base/include/foxglove_bridge/test/test_client.hpp

@@ -25,6 +25,8 @@ std::future<Service> waitForService(std::shared_ptr<ClientInterface> client,
 std::future<Channel> waitForChannel(std::shared_ptr<ClientInterface> client,
                                     const std::string& topicName);
 
+std::future<FetchAssetResponse> waitForFetchAssetResponse(std::shared_ptr<ClientInterface> client);
+
 extern template class Client<websocketpp::config::asio_client>;
 
 }  // namespace foxglove

foxglove_bridge_base/include/foxglove_bridge/websocket_client.hpp

@@ -50,6 +50,7 @@ class ClientInterface {
                              const std::optional<std::string>& requestId) = 0;
   virtual void subscribeParameterUpdates(const std::vector<std::string>& parameterNames) = 0;
   virtual void unsubscribeParameterUpdates(const std::vector<std::string>& parameterNames) = 0;
+  virtual void fetchAsset(const std::string& name, uint32_t requestId) = 0;
 
   virtual void setTextMessageHandler(TextMessageHandler handler) = 0;
   virtual void setBinaryMessageHandler(BinaryMessageHandler handler) = 0;
@@ -221,6 +222,11 @@ class Client : public ClientInterface {
     sendText(jsonPayload.dump());
   }
 
+  void fetchAsset(const std::string& uri, uint32_t requestId) override {
+    nlohmann::json jsonPayload{{"op", "fetchAsset"}, {"uri", uri}, {"requestId", requestId}};
+    sendText(jsonPayload.dump());
+  }
+
   void setTextMessageHandler(TextMessageHandler handler) override {
     std::unique_lock<std::shared_mutex> lock(_mutex);
     _textMessageHandler = std::move(handler);

foxglove_bridge_base/include/foxglove_bridge/websocket_server.hpp

@@ -69,6 +69,7 @@ const std::unordered_map<std::string, std::string> CAPABILITY_BY_CLIENT_OPERATIO
   {"unsubscribeParameterUpdates", CAPABILITY_PARAMETERS_SUBSCRIBE},
   {"subscribeConnectionGraph", CAPABILITY_CONNECTION_GRAPH},
   {"unsubscribeConnectionGraph", CAPABILITY_CONNECTION_GRAPH},
+  {"fetchAsset", CAPABILITY_ASSETS},
 };
 
 /// Map of required capability by client operation (binary).
@@ -131,6 +132,7 @@ class Server final : public ServerInterface<ConnHandle> {
   void sendServiceResponse(ConnHandle clientHandle, const ServiceResponse& response) override;
   void updateConnectionGraph(const MapOfSets& publishedTopics, const MapOfSets& subscribedTopics,
                              const MapOfSets& advertisedServices) override;
+  void sendFetchAssetResponse(ConnHandle clientHandle, const FetchAssetResponse& response) override;
 
   uint16_t getPort() override;
   std::string remoteEndpointString(ConnHandle clientHandle) override;
@@ -622,6 +624,7 @@ inline void Server<ServerConfiguration>::handleTextMessage(ConnHandle hdl, Messa
   constexpr auto UNSUBSCRIBE_PARAMETER_UPDATES = Integer("unsubscribeParameterUpdates");
   constexpr auto SUBSCRIBE_CONNECTION_GRAPH = Integer("subscribeConnectionGraph");
   constexpr auto UNSUBSCRIBE_CONNECTION_GRAPH = Integer("unsubscribeConnectionGraph");
+  constexpr auto FETCH_ASSET = Integer("fetchAsset");
 
   switch (Integer(op)) {
     case SUBSCRIBE: {
@@ -906,6 +909,22 @@ inline void Server<ServerConfiguration>::handleTextMessage(ConnHandle hdl, Messa
                             "Client was not subscribed to connection graph updates");
       }
     } break;
+    case FETCH_ASSET: {
+      if (!_handlers.fetchAssetHandler) {
+        return;
+      }
+
+      const auto uri = payload.at("uri").get<std::string>();
+      const auto requestId = payload.at("requestId").get<uint32_t>();
+
+      try {
+        _handlers.fetchAssetHandler(uri, requestId, hdl);
+      } catch (const std::exception& e) {
+        sendStatusAndLogMsg(hdl, StatusLevel::Error, e.what());
+      } catch (...) {
+        sendStatusAndLogMsg(hdl, StatusLevel::Error, op + ": Failed to execute handler");
+      }
+    } break;
     default: {
       sendStatusAndLogMsg(hdl, StatusLevel::Error, "Unrecognized client opcode \"" + op + "\"");
     } break;
@@ -1371,4 +1390,38 @@ inline bool Server<ServerConfiguration>::hasCapability(const std::string& capabi
          _options.capabilities.end();
 }
 
+template <typename ServerConfiguration>
+inline void Server<ServerConfiguration>::sendFetchAssetResponse(
+  ConnHandle clientHandle, const FetchAssetResponse& response) {
+  std::error_code ec;
+  const auto con = _server.get_con_from_hdl(clientHandle, ec);
+  if (ec || !con) {
+    return;
+  }
+
+  const size_t errMsgSize =
+    response.status == FetchAssetStatus::Error ? response.errorMessage.size() : 0ul;
+  const size_t dataSize = response.status == FetchAssetStatus::Success ? response.data.size() : 0ul;
+  const size_t messageSize = 1 + 4 + 1 + 4 + errMsgSize + dataSize;
+
+  auto message = con->get_message(OpCode::BINARY, messageSize);
+
+  const auto op = BinaryOpcode::FETCH_ASSET_RESPONSE;
+  message->append_payload(&op, 1);
+
+  std::array<uint8_t, 4> uint32Data;
+  foxglove::WriteUint32LE(uint32Data.data(), response.requestId);
+  message->append_payload(uint32Data.data(), uint32Data.size());
+
+  const uint8_t status = static_cast<uint8_t>(response.status);
+  message->append_payload(&status, 1);
+
+  foxglove::WriteUint32LE(uint32Data.data(), response.errorMessage.size());
+  message->append_payload(uint32Data.data(), uint32Data.size());
+  message->append_payload(response.errorMessage.data(), errMsgSize);
+
+  message->append_payload(response.data.data(), dataSize);
+  con->send(message);
+}
+
 }  // namespace foxglove

foxglove_bridge_base/src/server_factory.cpp

@@ -1,8 +1,6 @@
 #include <websocketpp/common/connection_hdl.hpp>
 
 #include <foxglove_bridge/server_factory.hpp>
-
-#define ASIO_STANDALONE
 #include <foxglove_bridge/websocket_notls.hpp>
 #include <foxglove_bridge/websocket_server.hpp>
 #include <foxglove_bridge/websocket_tls.hpp>

foxglove_bridge_base/src/test/test_client.cpp

@@ -1,6 +1,5 @@
 #include <chrono>
 
-#define ASIO_STANDALONE
 #include <websocketpp/config/asio_client.hpp>
 
 #include <foxglove_bridge/serialization.hpp>
@@ -132,7 +131,35 @@ std::future<Channel> waitForChannel(std::shared_ptr<ClientInterface> client,
         }
       }
     });
+  return future;
+}
+
+std::future<FetchAssetResponse> waitForFetchAssetResponse(std::shared_ptr<ClientInterface> client) {
+  auto promise = std::make_shared<std::promise<FetchAssetResponse>>();
+  auto future = promise->get_future();
 
+  client->setBinaryMessageHandler(
+    [promise = std::move(promise)](const uint8_t* data, size_t dataLength) mutable {
+      if (static_cast<BinaryOpcode>(data[0]) != BinaryOpcode::FETCH_ASSET_RESPONSE) {
+        return;
+      }
+
+      foxglove::FetchAssetResponse response;
+      size_t offset = 1;
+      response.requestId = ReadUint32LE(data + offset);
+      offset += 4;
+      response.status = static_cast<foxglove::FetchAssetStatus>(data[offset]);
+      offset += 1;
+      const size_t errorMsgLength = static_cast<size_t>(ReadUint32LE(data + offset));
+      offset += 4;
+      response.errorMessage =
+        std::string(reinterpret_cast<const char*>(data + offset), errorMsgLength);
+      offset += errorMsgLength;
+      const auto payloadLength = dataLength - offset;
+      response.data.resize(payloadLength);
+      std::memcpy(response.data.data(), data + offset, payloadLength);
+      promise->set_value(response);
+    });
   return future;
 }
 

package.xml

@@ -43,6 +43,7 @@
     <exec_depend>openssl</exec_depend>
     <exec_depend>zlib</exec_depend>
 
+    <depend>resource_retriever</depend>
     <depend>rosgraph_msgs</depend>
 
     <!-- The export tag contains other, unspecified, tags -->

ros1_foxglove_bridge/launch/foxglove_bridge.launch

@@ -12,7 +12,8 @@
   <arg name="send_buffer_limit"         default="10000000" />
   <arg name="nodelet_manager"           default="foxglove_nodelet_manager" />
   <arg name="num_threads"               default="0" />
-  <arg name="capabilities"              default="[clientPublish,parameters,parametersSubscribe,services,connectionGraph]" />
+  <arg name="capabilities"              default="[clientPublish,parameters,parametersSubscribe,services,connectionGraph,assets]" />
+  <arg name="asset_uri_allowlist"       default="['package://(/?\w+)+\.(dae|stl|urdf|xacro)']" />
 
   <node pkg="nodelet" type="nodelet" name="foxglove_nodelet_manager" args="manager"
         if="$(eval nodelet_manager == 'foxglove_nodelet_manager')">
@@ -34,5 +35,6 @@
     <rosparam param="service_whitelist"       subst_value="True">$(arg service_whitelist)</rosparam>
     <rosparam param="client_topic_whitelist"  subst_value="True">$(arg client_topic_whitelist)</rosparam>
     <rosparam param="capabilities"            subst_value="True">$(arg capabilities)</rosparam>
+    <rosparam param="asset_uri_allowlist"     subst_value="True">$(arg asset_uri_allowlist)</rosparam>
   </node>
 </launch>