[GTFS Full Support] Alerts

[jamespfennell]

Will need to create the following tables and parse types:

• alert_active_period. This is optional; if not provided, we should create a dummy one that covers all time. Foreign keys into alert.

• Join tables from alert to agency, route, trip, scheduled_trip, and stop. If the route type is provided, we will expand these to all routes in the system. For trip selectors, we can join onto both trip and scheduled_trip.

• alert_message, with columns header, description, url and language. Foreign keys into alert.

• Need to ensure cause and effect support all the GTFS static types.

Then, in the HTTP API, we will search for alerts based on the active period. We will return a JSON blob like:

{
    "id": "id",
    "cause": "TECHNICAL_PROBLEM",
    "effect": "SIGNIFICANT_DELAYS".
    "messages" [
        {
            "header": "..."
        }
     ],
     "started_at": "",
     "ends_at": "",
}

We may possibly inspect the NYCT Subway extension to see if there are extra fields worth putting in.

[jamespfennell]

https://github.com/OneBusAway/onebusaway-gtfs-realtime-api/blob/7c5a948c7e9b683b954f39d5aac64ab9b0326f52/src/main/resources/com/google/transit/realtime/gtfs-realtime-service-status.proto

[jamespfennell]

Reasonable fields from the MTA:

• updated_at
• created_at
• sort_order