CCXT.WS (ccxt_client v0.6.1)

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WebSocket entry point. Thin wrapper around ZenWebsocket.Client that binds a %CCXT.Exchange{} to a connection so subscribe/3 can pick the correct exchange-native frame builder.

Layer 1+2 (Task 92)

Pure URL resolution (CCXT.WS.URLRouting) + connection lifecycle (this module). Layer 3 (auth state machine, custom reconnection) is deliberately deferred — zen_websocket covers reconnection, backoff, heartbeat, and subscription restoration natively.

Usage

{:ok, ws} = CCXT.WS.connect(exchange, :public)
:ok = CCXT.WS.subscribe(ws, ["tickers.BTCUSDT"])
# Messages arrive at the calling process as {:websocket_message, decoded_map}
CCXT.WS.close(ws)

For deribit's JSON-RPC subscribe (which carries an id field), subscribe/3 returns {:ok, response} from zenwebsocket's request-correlation; for bybit and okx it returns :ok and the subscribe-ack arrives asynchronously as a `{:websocket_message, }` message.

Scope

Three canary exchanges are wired today: bybit, deribit, okx. Other priority-tier exchanges land in T93 (auth) + T94 (subscription patterns).

Summary

Functions

Closes the WebSocket connection.

Connects to the exchange's WebSocket endpoint for the given section (:public or :private).

Returns the current connection state (:connecting, :connected, or :disconnected).

Returns the resolved WS URL this connection is using.

Sends a raw (already-encoded or map) payload. Delegates to zen_websocket.

Sends an exchange-native subscribe frame for the given channels.

Types

section()

@type section() :: :public | :private

t()

@type t() :: %CCXT.WS{
  exchange: CCXT.Exchange.t(),
  section: section(),
  url: String.t(),
  zen_client: ZenWebsocket.Client.t()
}

Functions

close(ws)

@spec close(t()) :: :ok

Closes the WebSocket connection.

connect(exchange, section, opts \\ [])

@spec connect(CCXT.Exchange.t(), section(), keyword()) ::
  {:ok, t()} | {:error, term()}

Connects to the exchange's WebSocket endpoint for the given section (:public or :private).

Extra opts are forwarded to ZenWebsocket.Client.connect/2. The connection's heartbeat config is resolved from CCXT.WS.Config unless the caller overrides heartbeat_config in opts.

Returns {:error, :unsupported_exchange} if the exchange has no WS config, or {:error, :no_url_configured} if the requested section is absent.

get_state(ws)

@spec get_state(t()) :: :connecting | :connected | :disconnected

Returns the current connection state (:connecting, :connected, or :disconnected).

get_url(ws)

@spec get_url(t()) :: String.t()

Returns the resolved WS URL this connection is using.

send_message(ws, payload)

@spec send_message(t(), String.t() | map()) :: :ok | {:ok, map()} | {:error, term()}

Sends a raw (already-encoded or map) payload. Delegates to zen_websocket.

subscribe(ws, channels, opts \\ [])

@spec subscribe(t(), [String.t() | map()], keyword() | map()) ::
  :ok | {:ok, map()} | {:error, term()}

Sends an exchange-native subscribe frame for the given channels.

The frame is built by the exchange's registered subscription_pattern module (via CCXT.WS.Subscription.build_subscribe/3), encoded as JSON, and sent via ZenWebsocket.Client.send_message/2.

Pattern modules return either a single map (most exchanges) or a list of maps (:sub_subscribe, :reqtype_sub, and :custom with array_format — HTX/BingX/Upbit emit one frame per channel). List returns are sent sequentially; the function returns :ok only if every frame sent successfully.

For frames with an id field (deribit JSON-RPC), send_message/2 blocks on the correlated response and returns {:ok, response}. For frames without an id (bybit, okx, etc.), returns :ok.

Extra opts merge into the exchange's subscription_config from CCXT.WS.Config — used for runtime overrides like a fresh JSON-RPC id or an inline auth token. Keys must be atoms to override the atom-keyed base config; string-keyed maps coexist rather than override.

TODO(adapter): :rest_token (kraken) and :inline_subscribe (coinbase) auth patterns require per-frame auth injection via CCXT.WS.Auth.build_subscribe_auth/5, which this function does not call. Private subscribes on those exchanges ship unauthenticated until the adapter layer lands (see CHANGELOG T94).