Base classes

This package is built around a small set of base classes and typed role interfaces that make it easy to load perception "drivers" as plugins.

DriverBase

fp_perception::DriverBase is the common base class for all perception plugins.

Lifecycle

• initialize(const rclcpp::Node::SharedPtr&): called after plugin construction (pluginlib creates objects with a default constructor). The default implementation calls initialize_base(node).
• deinitialize(): pure virtual and must be implemented by every driver.
• test(): optional; default logs the driver name.

Standard diagnostics

• If use_diagnostics=true on the server node, drivers can publish status on the standard ROS 2 /diagnostics topic via diagnostic_updater.
• DriverBase provides the shared parameter read and updater/timer wiring; concrete drivers only populate their own health fields.

Typed role interfaces

Server and pipeline code use typed interfaces:

• AudioSourceDriver: microphone-like sources returning audio_data chunks.
• AudioSinkDriver: speaker-like sinks accepting audio_data playback.
• TranscriptionDriver: transcription providers accepting transcription_request.
• SpeechSynthesisDriver: TTS providers accepting text_data and returning audio_data.
• SentimentAnalysisDriver: sentiment providers accepting sentiment_request.
• VisionSourceDriver: camera-like sources returning vision_frame.
• ImageAnalysisDriver: image-analysis providers accepting image_analysis_request.

Common utilities

• check_directory(folder): creates a directory if missing (used by driver tests).
• check_file(path): throws if file does not exist.

RestBase

fp_perception::RestBase derives from DriverBase and provides a reusable REST client built on libcurl.

REST initialization

Drivers typically call:

initialize_rest_base(node, "<plugin_prefix>", "<ENV_KEY>")

This declares and loads common parameters under <plugin_prefix>.rest.*:

• <plugin_prefix>.rest.uri (string)
• <plugin_prefix>.rest.method (string, e.g. POST)
• <plugin_prefix>.rest.ssl_verify (bool)
• <plugin_prefix>.rest.auth_type (string, currently Bearer)

If ENV_KEY is provided, the API key is read from that environment variable (e.g. OPENAI_API_KEY, HUGGINGFACE_API_KEY).

Request helpers

RestBase provides:

• call(req): JSON request/response. Requires the derived driver to implement toJson() and fromJson().
• call_audio(req): multipart form upload (used for audio transcription).
• call_tts(req): JSON request that returns raw PCM audio (converted to std::vector<int16_t> in RESTResponse::audio_stream).

Important note about <tt>deinitialize()</tt>

RestBase does not implement deinitialize() (it remains pure via DriverBase). Any REST driver must implement deinitialize() to be instantiable by pluginlib.