rails linkedin gem: how to scan all user fields for emptiness

Question

quick question: i'm using the linkedin gem to pull user data, but my app breaks if a particular data field is blank on the user's linkedin profile. is there an optimal way to scan each profile for blankness in all data fields and pull only those that are present to prevent breaking?

here is my auth_controller...i know it is not DRY and in need of refactoring. Thanks!

require 'linkedin'

class AuthController < ApplicationController

  def index
    client = LinkedIn::Client.new(ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET'])
    request_token = client.request_token(:oauth_callback => 
                                      "http://#{request.host_with_port}/callback")
    session[:rtoken] = request_token.token
    session[:rsecret] = request_token.secret
    redirect_to client.request_token.authorize_url
  end

  def callback
    client = LinkedIn::Client.new(ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET'])
    if session[:atoken].nil?
      pin = params[:oauth_verifier]
      atoken, asecret = client.authorize_from_request(session[:rtoken], session[:rsecret], pin)
      session[:atoken] = atoken
      session[:asecret] = asecret
    else
      client.authorize_from_access(session[:atoken], session[:asecret])
    end

        current_user = client.profile(:fields => %w(positions educations))
        @user = current_user
        educations = current_user.educations.all
        positions = current_user.positions.all

        companies = current_user.positions.all.map{ |t| t.company }

        @current_company = companies[0]['name']
      @past_company_one = companies[1]['name']
      @past_company_two = companies[2]['name']
      @past_company_three = companies[3]['name']

      @current_industry = companies[0]['industry']
    @past_industry_one = companies[1]['industry']
    @past_industry_two = companies[2]['industry']
    @past_industry_three = companies[3]['industry']

        @first_name = client.profile(:fields => ["first_name"]).first_name
    @last_name = client.profile(:fields => ["last_name"]).last_name
    @headline = client.profile(:fields => ["headline"]).headline
        @picture = client.profile(:fields => ["picture-url"]).picture_url

        @school_one_name = educations[0]['school-name']
        @school_one_degree = educations[0]['degree']
    @school_one_field = educations[0]['field-of-study']
    @school_one_start = educations[0]['start-date']['year'].to_s
    @school_one_end = educations[0]['end-date']['year'].to_s

    @school_two_name = educations[1]['school-name']
        @school_two_degree = educations[1]['degree']
    @school_two_field = educations[1]['field-of-study']
    @school_two_start = educations[1]['start-date']['year'].to_s
    @school_two_end = educations[1]['end-date']['year'].to_s

    @current_title = positions[0]['title']
    @past_title_one = positions[1]['title']
    @past_title_two = positions[2]['title']
    @past_title_three = positions[3]['title']

    @current_start_date = Date::MONTHNAMES[positions[0]['start-date']['month']] + " " + positions[0]['start-date']['year'].to_s

    @past_start_date_one = Date::MONTHNAMES[positions[1]['start-date']['month']] + " " + positions[1]['start-date']['year'].to_s
    @past_end_date_one = Date::MONTHNAMES[positions[1]['end-date']['month']] + " " + positions[1]['end-date']['year'].to_s

    @past_start_date_two = Date::MONTHNAMES[positions[2]['start-date']['month']] + " " + positions[2]['start-date']['year'].to_s
    @past_end_date_two = Date::MONTHNAMES[positions[2]['end-date']['month']] + " " + positions[2]['end-date']['year'].to_s

    @past_start_date_three = Date::MONTHNAMES[positions[3]['start-date']['month']] + " " + positions[3]['start-date']['year'].to_s
    @past_end_date_three = Date::MONTHNAMES[positions[3]['end-date']['month']] + " " + positions[3]['end-date']['year'].to_s

  end
end

Answer 1

considering your current code may break upon any unexpected values in the response and assuming it's happening in your above callback method, you may consider just applying quick'n'dirty exception handling to your code.

for example, by simply enclosing the potentially offending code in a begin / end block and using a rescue clause to handle any exceptions:

def callback
  client = LinkedIn::Client.new(ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET'])

  if session[:atoken].nil?
    # ...code
    else
    #...code
  end

  # start handling exceptions here
  begin
    # ...potentially offending code here
    current_user = client.profile(:fields => %w(positions educations))
    # ...more code
    @past_end_date_three = Date::MONTHNAMES[positions[3]['end-date']['month']] + " " + positions[3]['end-date']['year'].to_s
  rescue
    # oops, something happened:
    # ...your code to handle the exception here
  end

end