ExUssd

Goals:

• An idiomatic, readable, and comfortable API for Elixir developers
• Extensibility based on small parts that do one thing well.
• Detailed error messages and documentation.
• A focus on robustness and production-level performance.

Why Use ExUssd?

ExUssd lets you create simple, flexible, and customizable USSD interface. Under the hood ExUssd uses Elixir Registry to create and route individual USSD session.

Documentation

The docs can be found at https://hexdocs.pm/ex_ussd

Installation

The package can be installed by adding ex_ussd to your list of dependencies in mix.exs:

defp deps do
  [
    {:ex_ussd, "~> 1.1.0"}
  ]
end

Configuration

Add to your config.exs

# config/config.exs
# TODO: This are example values, replace them with your own
config :ex_ussd,
  nav: [
    ExUssd.Nav.new(type: :home, name: "HOME", match: "00", reverse: true, orientation: :vertical),
    ExUssd.Nav.new(type: :back, name: "BACK", match: "0", right: 1),
    ExUssd.Nav.new(type: :next, name: "MORE", match: "98")
  ],
  delimiter: ").",
  default_error: "invalid input,try again\n"

Usage

ExUssd Callbacks

ExUssd provides you with 3 callbacks

Example

Create a new module:

defmodule ApiWeb.HomeResolver do
  use ExUssd
  
  def ussd_init(menu, _payload) do
    {:ok, ExUssd.set(menu, title: "Enter your PIN")}
  end

  def ussd_callback(menu, payload, %{attempt: %{count: count}}) do
    if payload.text == "5555" do
      menu =
        menu
        |> ExUssd.set(data: %{name: "John"}) # use payload `phone_number` to fetch the user from DB
        |> ExUssd.set(resolve: &home_rc/2)
      {:ok, menu}
    else
      {:error, "Wrong PIN, #{2 - count} attempt left"}
    end
  end

  def ussd_after_callback(%{error: true} = menu, _payload, %{attempt: %{count: 3}}) do
    menu = 
      menu
      |> ExUssd.set(title: "Account is locked, Dial *234# to reset your account")
      |> ExUssd.set(should_close: true)
    {:ok, menu}
  end

  def home_rc(%ExUssd{data: %{name: name}} = menu, _) do
    menu =  
      menu
      |> ExUssd.set(title: "Welcome #{name}!")
      |> ExUssd.add(ExUssd.new(name: "option 1"))
      |> ExUssd.add(ExUssd.new(name: "option 2"))
      |> ExUssd.set(show_navigation: false) # hide navigation options
    {:ok, menu}
  end
end

Contribution

If you'd like to contribute, start by searching through the issues and pull requests to see whether someone else has raised a similar idea or question. If you don't see your idea listed, Open an issue.

Check the Contribution guide on how to contribute.

Contributors

Auto-populated from: contributors-img

Licence

ExUssd is released under Apache License 2.0.