ZenWebsocket.Examples.Docs.ErrorHandling (ZenWebsocket v0.8.0)

A GenServer that owns a connection and retries it with backoff.

Demonstrates owning a Client.connect/2 result in GenServer state, rescheduling Client.connect/2 on failure while counting attempts, and handling the {:websocket_message, _}, {:websocket_unmatched_response, _} and {:websocket_protocol_error, _} messages the default handler forwards to the owning process. Those three are the only messages ZenWebsocket.Client.CallFacade sends; a transport error surfaces as a {:error, reason} return from Client.connect/2 or Client.send_message/2, never as a mailbox message.

Summary

Types

state()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

get_state()

Returns the current state of the error handler.

send_message(message)

Sends a message through the WebSocket connection.

start_link(url, opts \\ [])

Starts a GenServer that manages a WebSocket connection with automatic retry.

Types

state()

@type state() :: %{
  client: pid() | nil,
  url: String.t(),
  opts: keyword(),
  retry_count: non_neg_integer()
}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

get_state()

@spec get_state() :: state()

Returns the current state of the error handler.

Returns

The internal state map including connection status and retry count.

send_message(message)

@spec send_message(binary()) :: :ok | {:ok, map()} | {:error, term()}

Sends a message through the WebSocket connection.

Parameters

message - Message to send (must be a binary — use Jason.encode!/1 for maps)

Returns

:ok on success
{:error, :not_connected} if not connected
{:error, {:not_connected, reason}} if client is disconnected or process is down

start_link(url, opts \\ [])

@spec start_link(
  String.t(),
  keyword()
) :: GenServer.on_start()

Starts a GenServer that manages a WebSocket connection with automatic retry.

Parameters

url - WebSocket URL to connect to
opts - Connection options

Returns

{:ok, pid} on success or {:error, reason} on failure.