Db2Session

gem 'db2_session'

# app_root/config/initializers/db2query.rb

require "db2_session"

Db2Query::Base.initiation do |base|
  base.set_field_types
end

Db2Session::ApplicationQuery.establish_connection

Rails.application.routes.draw do
  mount Db2Session::Engine => "/db2_session"
  ...
end

# app/queries/application_query.rb
class ApplicationQuery < Db2Session::ApplicationQuery
  def self.inherited(subclass)
    subclass.define_query_definitions
  end
end

# app/queries/db2_connection_query.rb
class Db2ConnectionQuery < ApplicationQuery
  def status_sql
    "SELECT 1 AS CONNECTED FROM SYSIBM.SYSDUMMY1"
  end
end

# app/queries/definitions/db2_connection_query_definitions.rb
module Definitions
  class Db2ConnectionQueryDefinitions < Db2Query::Definitions
    def describe
      query_definition :status do |c|
        c.connected :boolean
      end
    end
  end
end

# app/controllers/db2_session/controller.rb
module Db2Session
  class Controller < Db2Session::ApplicationController
    private
      def request_token
        return nil unless request.authorization
        request.authorization.split(" ").last
      end
  end
end

# app/controllers/db2_connection_controller.rb
class Db2ConnectionController < Db2Session::Controller
  def index
    status = Db2ConnectionQuery.status
    render json: {
      data: {
        user: Db2ConnectionQuery.connection.userid,
        trx_time: Db2ConnectionQuery.connection.trx_time,
        connected: status.connected
      }
    }
  end
end

Rails.application.routes.draw do
  mount Db2Session::Engine => "/db2_session"
  get "/db2_connection", to: "db2_connection#index"
end

 {"data":{"user":"YOHANES","trx_time":14556.481167844,"connected":true}}

# app/controller/graphql_controller.rb
class GraphqlController < Db2Session::Controller
...
end

# app/assets/config/manifest.js
//= link_tree ../images
//= link_directory ../stylesheets .css

# config/initializers/assets.rb
if Rails.env.development?
  Rails.application.config.assets.precompile += %w[graphiql/rails/application.js graphiql/rails/application.css]
end

# app/controllers/graphiql/rails/editors_controller.rb
module GraphiQL
  module Rails
    class EditorsController < ActionController::Base
      attr_reader :auth_token

      include Db2Session::Manager

      before_action :authenticate
      def show
        GraphiQL::Rails.config.headers["Authorization"] = -> (_) { "Bearer #{auth_token}" }
      end

      helper_method :graphql_endpoint_path
      def graphql_endpoint_path
        params[:graphql_path] || raise(%|You must include `graphql_path: "/my/endpoint"` when mounting GraphiQL::Rails::Engine|)
      end

      protected
        def authenticate
          unless auth_token
            authenticate_or_request_with_http_basic do |username, password|
              params[:userid] = username
              params[:password] = password
              connection = fetch_or_create_connection
              connection.trx_time = current_time
              @auth_token = token(connection.object_id)
            rescue
              false
            end
          end
        end

        def connections
          sessions.keys.map do |key|
            conn = sessions.fetch(key)
            conn.userid == params[:userid] ? conn : nil
          end
        end

        def fetch_or_create_connection
          connections.first || create_new_connection
        end
    end
  end
end

# config/routes.rb
Rails.application.routes.draw do
  ...
  post "/graphql", to: "graphql#execute"

  if Rails.env.development?
    get "/graphiql" => "graphiql/rails/editors#show", graphql_path: "/graphql"
  end
  ...
end

# app/graphql/types/connection_status.rb
module Types
  class ConnectionStatus < Types::BaseObject
    field :user, String, null: true
    field :trx_time, Integer, null: true
    field :connected, Boolean, null: true
  end
end

# app/graphql/types/query_type.rb
module Types
  class QueryType < Types::BaseObject
    ...
    field :connection_status, resolver: Queries::ConnectionStatusQuery
    ...
  end
end

# app/graphql/queries/connection_status_query.rb
module Queries
  class ConnectionStatusQuery < GraphQL::Schema::Resolver
    type Types::ConnectionStatus, null: false

    def resolve
      {
        user: connection.userid,
        trx_time: connection.trx_time,
        connected: status.connected
      }
    end

    protected
      def status
        Db2ConnectionQuery.status
      end

      def connection
        Db2ConnectionQuery.connection
      end
  end
end

# app/test/test_helper.rb

module Db2Session
  class  IntegrationTest < ActionDispatch::IntegrationTest
    attr_reader :request_token

    include Db2Session::Manager

    setup do
      # get the credentials from environment variable
      user_1 = ENV["USER1_ID"]   
      user_1_password = ENV["USER1_PASSWORD"]

      db2_session = Db2Session::Engine.routes.url_helpers
      post db2_session.login_path, params: { userid: user_1, password: user_1_password }, as: :json
      @request_token = @response["Authorization"].split(" ").last

      Thread.current[:connection] = current_connection
    end
  end
end

# app/test/queries/db2_connection_query_test.rb

require "test_helper"

class Db2ConnectionQueryTest < Db2Session::IntegrationTest
  test "connection status" do
    status = Db2ConnectionQuery.status
    assert status.connected
  end
end