OAuth2 with Refresh Token

client.rb

require "oauth2"
require_relative "token"

module Api
  class Client
    def initialize(client_id:, client_secret:, endpoint:)
      @client_id = client_id
      @client_secret = client_secret
      @endpoint = endpoint
    end

    def token(options = {})
      if ([:username, :password] - options.keys).empty?
        password_token(options)
      else
        client_token
      end
    end

    def client_token
      Token.new(token: client.client_credentials.get_token)
    end

    def password_token(username:, password:)
      Token.new(token: client.password.get_token(username, password))
    end

    private

    attr_reader :client_id, :client_secret, :endpoint

    def client
      @_client ||= OAuth2::Client.new(client_id, client_secret, site: endpoint)
    end
  end
end

example.rb

#!/usr/bin/env ruby

require_relative "client.rb"
require "pry"

client = Api::Client.new({
  client_id: "",
  client_secret: "",
  endpoint: ""
})

puts "Client Token"
client_token = client.token
puts client_token.get("/version").body
puts "Sleep for expiry"
sleep client_token.expires_in + 1
puts client_token.get("/version").body

puts "Password Token"
password_token = client.token(username: "", password: "")
puts password_token.get("/version").body
puts "Sleep for expiry"
sleep password_token.expires_in + 1
puts password_token.get("/version").body

token.rb

module Api
  class Token
    REQUEST_METHODS = %w(get put post delete request).freeze

    def initialize(token:)
      @token = token
    end

    REQUEST_METHODS.each do |method|
      define_method(method) do |path, options: {}|
        token.send(method, path, options)
      end
    end

    private

    def token
      refresh_token if expired?
      @token
    end
    
    def expired?
      @token.expires_at <= Time.new.to_i
    end

    def refresh_token
      if client_token?
        @token = @token.client.client_credentials.get_token
      else
        @token = @token.refresh!
      end
    end

    def client_token?
      @token.refresh_token.nil?
    end
  end
end