API
Suppose you're tired of manually fiddling with traffic signals, and you want to use machine learning to do it. You can run A/B Street without graphics and automatically control it through an API.
Example
This Python example has everything you need to get started.
API details
Under construction: The API will keep changing. There are no backwards compatibility guarantees yet. Please make sure I know about your project, so I don't break your client code.
For now, the API is JSON over HTTP. The exact format is unspecified, error codes are missing, etc. A summary of the commands available so far:
- /sim
- GET /sim/reset: Reset all map edits and the simulation state. The trips
that will run don't change; they're determined by the scenario file you
initially pass to
headless. - GET /sim/get-time: Returns the current simulation time.
- GET /sim/goto-time?t=06:30:00: Simulate until 6:30 AM. If the time you specify is before the current time, you have to call /sim/reset first.
- GET /sim/reset: Reset all map edits and the simulation state. The trips
that will run don't change; they're determined by the scenario file you
initially pass to
- /traffic-signals
- GET /traffic-signals/get?id=42: Returns the traffic signal of intersection #42 in JSON.
- POST /traffic-signals/set: The POST body must be a traffic signal in JSON format.
- GET /traffic-signals/get-delays?id=42&t1=03:00:00&t2=03:30:00: Returns the delay experienced by every agent passing through intersection #42 from 3am to 3:30, grouped by direction of travel.
- GET /traffic-signals/get-cumulative-thruput?id=42: Returns the number of agents passing through intersection #42 since midnight, grouped by direction of travel.
- /data
- GET /data/get-finished-trips: Returns a JSON list of all finished trips. Each tuple is (time the trip finished in seconds after midnight, trip ID, mode, duration of trip in seconds). The mode is either a string like "Walk" or "Drive", or null if the trip was aborted (due to a simulation bug or disconnected map).
- GET /data/get-agent-positions: Returns a JSON list of all active agents. Vehicle type (or pedestrian), person ID, and position is included.
- /map
- GET /map/get-edits: Returns the current map edits in JSON. You can save
this to a file in
data/player/edits/map_name/and later use it in-game normally. You can also later run theheadlessserver with--edits=name_of_edits.
- GET /map/get-edits: Returns the current map edits in JSON. You can save
this to a file in
Related tools
There's no API to create trips. Instead, you can import trips from your own data.
If you need to deeply inspect the map, you can dump it to JSON:
cargo run --bin iotool -- dump_map --map=data/system/maps/montlake.bin
The format of the map isn't well-documented yet. See the generated API docs and the map model docs in the meantime.