gtfs-rt

// SPDX-FileCopyrightText: 2023 Friedrich-Alexander-Universitat Erlangen-Nurnberg
//
// SPDX-License-Identifier: AGPL-3.0-only

// Example 3: GTFS Realtime Data
// Learning goals:
// - Understand the construction of a csv file with multiple tables
// - Understand how to work with live data

// 1. This Jayvee model describes a pipeline 
// from a GTFS RT data source in the web 
// to a SQLite file with multiple tables.
pipeline GtfsRTSimplePipeline {

  // 2. As you can see here, we have three independent
  // sequences of pipes in this pipeline.
  GTFSRTTripUpdateFeedExtractor
    ->GtfsRTTripUpdateInterpreter
    ->TripUpdateTableInterpreter
    ->TripUpdateLoader;

  GTFSRTVehiclePositionFeedExtractor
    ->GtfsRTVehiclePositionInterpreter
    ->VehiclePositionTableInterpreter
    ->VehicleLoader;

  GTFSRTAlertFeedExtractor
    ->GtfsRTAlertInterpreter
    ->AlertTableInterpreter
    ->AlertLoader;

  // 3. We define a series of HttpExtractors that each pull data
  // from an HTTP endpoint
  block GTFSRTTripUpdateFeedExtractor oftype HttpExtractor {
    url: "https://proxy.transport.data.gouv.fr/resource/bibus-brest-gtfs-rt-trip-update";
  }

  block GTFSRTVehiclePositionFeedExtractor oftype HttpExtractor {
    url: "https://proxy.transport.data.gouv.fr/resource/bibus-brest-gtfs-rt-vehicle-position";
  }

  block GTFSRTAlertFeedExtractor oftype HttpExtractor {
    url: "https://proxy.transport.data.gouv.fr/resource/bibus-brest-gtfs-rt-alerts";
  }

  // 4. In the next step, we use the domain-specific GtfsRTInterpreter
  // to interpret the fetched files as sheets
  block GtfsRTTripUpdateInterpreter oftype GtfsRTInterpreter {
    entity: "trip_update";
  }

  block GtfsRTAlertInterpreter oftype GtfsRTInterpreter {
    entity: "alert";
  }

  block GtfsRTVehiclePositionInterpreter oftype GtfsRTInterpreter {
    entity: "vehicle";
  }

  // 5. Next, we interpret the sheets as tables
  block TripUpdateTableInterpreter oftype TableInterpreter {
    header: true;
    columns: [
      "header.gtfs_realtime_version" oftype text,
      "header.timestamp" oftype text,
      "header.incrementality" oftype text,
      "entity.id" oftype text,
      "entity.trip_update.trip.trip_id" oftype text,
      "entity.trip_update.trip.route_id" oftype text,
      "entity.trip_update.stop_time_update.stop_sequence" oftype text,
      "entity.trip_update.stop_time_update.stop_id" oftype text,
      "entity.trip_update.stop_time_update.arrival.time" oftype text,
      "entity.trip_update.stop_time_update.departure.time" oftype text,
    ];
  }

  block VehiclePositionTableInterpreter oftype TableInterpreter {
    header: true;
    columns: [
      "header.gtfs_realtime_version" oftype text,
      "header.timestamp" oftype text,
      "header.incrementality" oftype text,
      "entity.id" oftype text,
      "entity.vehicle_position.vehicle_descriptor.id" oftype text,
      "entity.vehicle_position.trip.trip_id" oftype text,
      "entity.vehicle_position.trip.route_id" oftype text,
      "entity.vehicle_position.position.latitude" oftype text,
      "entity.vehicle_position.position.longitude" oftype text,
      "entity.vehicle_position.timestamp" oftype text
    ];
  }

  block AlertTableInterpreter oftype TableInterpreter {
    header: true;
    columns: [
      'header.gtfs_realtime_version' oftype text,
      'header.timestamp' oftype text,
      'header.incrementality' oftype text,
      'entity.id' oftype text,
      'entity.alert.informed_entity.route_id' oftype text,
      'entity.alert.header_text' oftype text,
      'entity.alert.description_text' oftype text,
    ];
  }

  // 6. Last, we load the tables into the same SQLite file.
  // Each loader has to define a different table name.
  // For working with live data, we use the property "dropTable: false"
  // to append data instead of deleting the previous data.
  block TripUpdateLoader oftype SQLiteLoader {
    table: "gtfs-rt-trip_update";
    file: "./gtfs.sqlite";
    dropTable: false;
  }

  block VehicleLoader oftype SQLiteLoader {
    table: "gtfs-rt-vehicle_position";
    file: "./gtfs.sqlite";
    dropTable: false;
  }

  block AlertLoader oftype SQLiteLoader {
    table: "gtfs-rt-alert";
    file: "./gtfs.sqlite";
    dropTable: false;
  }
}