ExTwelveData

Unofficial Elixir client for Twelve Data.

Currently, it only covers the real-time prices WebSocket API.

Happy to accept contributions to support the other endpoints.

Usage

Real-time prices client

Twelve Data offers a WebSocket based API for real-time prices¹. ExTwelveData uses the WebSockex library to access this endpoint. Because of this, the WebSocket client runs as a supervised process.

The ExTwelveData.RealTimePrices.Handler behaviour requires a single callback, invoked whenever the client receives a price update from Twelve Data.

defmodule Your.Handler do
  @behaviour ExTwelveData.RealTimePrices.Handler
  
  @impl true
  def handle_price_update(price) do
    # Here you can process inbound price updates
    :ok
  end  
end

defmodule Your.Application do
  use Application
  alias ExTwelveData.RealTimePrices
  
  def start(_type, _args) do
    children = [
      {RealTimePrices, name: Your.Name, api_key: "abc", handler: Your.Handler},
    ]
    
    Supervisor.start_link(children, strategy: :one_for_one)
  end
end

With the process running, you can now subscribe, unsubscribe, and reset the subscriptions.

# Send a list of Twelve Data symbols to subscribe to
ExTwelveData.RealTimePrices.subscribe(Your.Name, ["BTC/USD", "AAPL"])

# Use the PID or process name to address the messages
ExTwelveData.RealTimePrices.unsubscribe(Your.Name, ["AAPL"])

# This stops listening for all updates, while keeping the client running
ExTwelveData.RealTimePrices.reset(Your.Name)

The client currently takes care of reconnecting, and sending the heartbeat every 10 seconds.

Installation

If available in Hex, the package can be installed by adding ex_twelve_data to your list of dependencies in mix.exs:

def deps do
  [
    {:ex_twelve_data, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/ex_twelve_data.

Reference