AisStream (aisstream v0.1.0)

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Unofficial client for the AISStream WebSocket API.

Sends every message to the :to process as {:aisstream, message} (decoded JSON) and reconnects on its own.

{:ok, _pid} =
  AisStream.start_link(
    api_key: System.fetch_env!("AISSTREAM_API_KEY"),
    bounding_boxes: [[[43.0, 7.5], [44.6, 10.5]]],
    filter_message_types: ["PositionReport"],
    to: self()
  )

receive do
  {:aisstream, %{"MessageType" => type}} -> IO.puts(type)
end

Options

  • :api_key (required) - API key, or a zero-arity function returning it (use the function under a supervisor, to keep the key out of its reports).
  • :bounding_boxes (required) - list of boxes, each [[lat1, lon1], [lat2, lon2]].
  • :filter_message_types - list of message types, e.g. ["PositionReport"].
  • :to (required) - pid or registered name receiving the messages. The client stops when a pid exits; with a name not registered at that moment, messages are dropped.
  • :name - name to register the client process under.
  • :ping_interval - keepalive interval in ms, default 30_000.
  • :max_queue_len - drop messages while the local :to process has this many queued, logging a warning at most once a minute. Best-effort, not backpressure; remote processes always receive. Default nil (no limit).
  • :url - default wss://stream.aisstream.io/v0/stream.

Summary

Types

option()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

start_link(opts)

Starts the client.

Types

option()

@type option() ::
  {:api_key, String.t() | (-> String.t())}
  | {:bounding_boxes, [[[number()]]]}
  | {:filter_message_types, [String.t()]}
  | {:to, pid() | atom()}
  | {:name, GenServer.name()}
  | {:ping_interval, pos_integer()}
  | {:max_queue_len, pos_integer() | nil}
  | {:url, String.t()}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

start_link(opts)

@spec start_link([option()]) :: GenServer.on_start()

Starts the client.

Raises ArgumentError on an unknown option or an invalid :ping_interval, :max_queue_len or :url, and KeyError if :api_key, :bounding_boxes or :to is missing.