Exercise using the NationBuilder People API endpoint

nation_builder_people.rb

#
# This is very rudimentary web app that allows you to create, update, and
# delete a Person record using the NationBuilder API. This covers just the
# basics - many details have been left out.
#
# The app was built in Ruby 2.2.0, using the Sinatra web framework, and the
# NationBuilder API Ruby gem.
#
# To run the app:
#   * gem install sinatra
#   * gem install nationbuilder-rb
#   * set environment variables NB_SLUG and NB_API_KEY to your NationBuilder slug and
#     API key respectively
#   * ruby nation_builder_people.rb
#   * point your browser to http://localhost:4567/people
#
require "sinatra"
require "nationbuilder"

# This class wraps the NationBuilder API gem, exposing a Person-centric interface
class NBClient

  class << self

    def create_person(person_params)
      execute_call do
        client.call(:people, :create, { person: person_params })["person"]
      end
    end

    def fetch_person(id)
      execute_call do
        client.call(:people, :show, id: id)["person"]
      end
    end

    def update_person(person_params)
      execute_call do
        client.call(:people, :update, id: person_params["id"], person: person_params)["person"]
      end
    end

    def delete_person(id)
      execute_call do
        client.call(:people, :destroy, id: id)
      end
    end

    private

    def client
      @client ||= NationBuilder::Client.new(ENV["NB_SLUG"], ENV["NB_API_KEY"], retries: 8)
    end

    def execute_call
      result = {}
      error = nil
      begin
        result = yield
      rescue Exception => e
        error = e.to_s
      end
      [result, error]
    end
  end

end

###################################
# Web app pages

# displays an empty form for creating a new Person
get "/people" do
  html = <<-END_HTML
    #{show_form(person: {})}
  END_HTML
end

# uses the form data to create a Person in NationBuilder and display the results
post "/people/create" do
  (result, error) = NBClient.create_person(params)
  if error
    show_form(person: result, error: error)
  else
    redirect to("/people/edit/#{result["id"]}?message=Created")
  end
end

# displays the current Person record in an editable form
get "/people/edit/:id" do
  (result, error) = NBClient.fetch_person(params[:id])
  html = <<-END_HTML
    #{show_form(person: result, error: error)}
  END_HTML
end

# handles updating the Person record in NationBuilder
post "/people/update/:id" do
  (result, error) = NBClient.update_person(request.params)
  if error
    show_form(person: result, error: error)
  else
    redirect to("/people/edit/#{result["id"]}?message=Updated")
  end
end

# deletes the Person record in NationBuilder and displays a new empty form
post "/people/delete/:id" do
  (result, error) = NBClient.delete_person(params[:id])
  if error
    redirect to("/people/edit/#{params[:id]}?message=#{error}")
  else
    redirect to("/people?message=Deleted")
  end
end

private

# the main UI
def show_form(person: {}, error: "")
  new_record = person["id"].nil?
  method = new_record ? "/people/create" : "/people/update/#{person["id"]}"
  form = <<-END_HTML
    <form action="#{method}" method="post">
      <p>#{params[:message]}</p>
      <p>#{error}</p>
      <table>
        <tr>
          <td>First name:</td>
          <td><input type="text" name="first_name" value="#{person["first_name"]}"></td>
        </tr>
        <tr>
          <td>Last name:</td>
          <td><input type="text" name="last_name" value="#{person["last_name"]}"></td>
        </tr>
        <tr>
          <td>Email:</td>
          <td><input type="text" name="email" value="#{person["email"]}"></td>
        </tr>
        <tr>
          <td>Phone:</td>
          <td><input type="text" name="phone" value="#{person["phone"]}"></td>
        </tr>
      </table>
      <input type="hidden" name="id" value="#{person["id"]}">
      <input type="submit" value="#{new_record ? "Create" : "Update"}">
    </form>
    #{ new_record ? "" : show_delete_form(person["id"]) }
  END_HTML
end

def show_delete_form(id)
  form = <<-END_HTML
    <form action="/people/delete/#{id}" method="post">
      <input type="submit" value="Delete">
    </form>
  END_HTML
end