Steemex

Elixir HTTP/Websockets client for Steem JSONRPC interface and official Steemit API.

Installation

1. Add steemex to your list of dependencies in mix.exs:

   def deps do
      [
        {:steemex, ">= 0.0.0"}
      ]
    end

Configuration

Stemeex doesn't require any configuration. If no config is provided, Steemex will use http://api.steemit.com condenser endpoint for all JSONRPC calls.

If you want to use another transport, public node or private node, set corresponding values for api and api_url. Possible api values are :steemit_api, :jsonrpc_ws_api, :jsonrpc_http_api.

If you are using http or ws api, you need to set a steemd instance url, for example, a public node http://gtg.steem.house:8090 for jsonrpc_http_api.

Example:

config :steemex,
  api: :jsonrpc_http_api,
  api_url: "http://gtg.steem.house:8090",
  activate_stage_sup: false

If want Steemex to stream incoming events in pseudo-realtime, set activate_stage_sup to true and see the example of a GenStage consumer.

JSONRPC API

Steemex module includes structs for all operations types. Streamer module parses each operation and converts it to a corresponding struct.

The main module function is Steemex.call. It will block the calling process and return a success tuple with a "result" data from the JSONRPC call response. JSONRPC call ids are handled automatically.

Documentation

All database api functions have docs, typespecs and example API responses.

GenStage

Steemex uses GenStage, a new specification for handling and exchanging events among Elixir/Erlang processes.

On module app startup two GenStage processes are started and registered:

• Steemex.Stage.Blocks.Producer which, perhaps unsurprisingly, is a new blocks producer
• Steemex.Stage.RawOps produces raw blockchain operations
• Steemex.Stage.MungedOps produces parsed, cleaned and transformed operations

An example of GenStage consumer to handle stream of new operations

defmodule Steemex.Stage.ExampleConsumer do
  use GenStage
  alias Steemex.MungedOps
  require Logger

  def start_link(args, options \\ []) do
    GenStage.start_link(__MODULE__, args, options)
  end

  def init(state) do
    Logger.info("Example consumer is initializing...")
    {:consumer, state, subscribe_to: state[:subscribe_to]}
  end

  def handle_events(events, _from, state) do
    for op <- events do
      process_event(op)
    end
    {:noreply, [], state}
  end

  def process_event(%{data: %MungedOps.Reblog{} = data, metadata: %{block_height: h, timestamp: t} = metadata}) do
      Logger.info """
      New reblog:
      #{inspect data}
      with metadata
      #{inspect metadata}
      """
  end

  def process_event(%{data: data, metadata: %{block_height: h, timestamp: t} = metadata}) do
      Logger.info """
      New operation:
      #{inspect data}
      with metadata
      #{inspect metadata}
      """
  end

end

Roadmap

Steemex is under active development.

• Add more utility functions
• Add more types and structs
• Add transaction broadcasting