Question

I’m trying to call a method when a button is clicked to go and fetch a tweet using the Twitter gem, and store that in my database.

I have a model called Sponsor (which includes a column storing a twitter user name), and a model called Sponsortweet:

models/sponsor.rb:

class Sponsor < ActiveRecord::Base                                                      
  attr_accessible :facebook, :name, :twitter                                         
  has_many :sponsortweets, dependent: :destroy                                          
                                                                                          validates :name, presence: true, uniqueness: { case_sensitive: false }                
  VALID_TWITTER_REGEX = /\A^([a-zA-Z](_?[a-zA-Z0-9]+)*_?|_([a-zA-Z0-9]+_?)*)$/          
  validates :twitter, format: { with: VALID_TWITTER_REGEX },                            
                      uniqueness: { case_sensitive: false }                             


  def create_tweet                                                                      
    tweet = Twitter.user_timeline(self.twitter).first                                   
    self.sponsortweets.create!(content: tweet.text,                                     
                               tweet_id: tweet.id,                                      
                               tweet_created_at: tweet.created_at,                      
                               profile_image_url: tweet.user.profile_image_url,         
                               from_user: tweet.from_user,)                             
  end                                                                                   
end

models/sponsortweet.rb:

class Sponsortweet < ActiveRecord::Base
  attr_accessible :content, :from_user, :profile_image_url, :tweet_created_at, :tweet_id
    belongs_to :sponsor
    validates :content, presence: true
    validates :sponsor_id, presence: true

    default_scope order: 'sponsortweets.created_at DESC'
end

In controllers/sponsors_controller.rb:

def tweet
        @sponsor = Sponsor.find_by_id(params[:id])
        @sponsor.create_tweet
    end

Relevant line in my routes.rb:

match 'tweet', to: 'sponsors#tweet', via: :post

In my view (views/sponsors/show.html.haml):

= button_to :tweet, tweet_path

With this code, I get the following error when clicking on the button:
undefined methodcreate_tweet’ for nil:NilClass`

If I change to use find (instead of find_by_id), the error is:
Couldn't find Sponsor without an ID

…which makes me think that an ID isn’t being passed, since as far as I know, using find raises an error, whereas find_by_id returns nil.

What should I change to cause an ID to be passed?

Answer 1

You need to pass through the id parameter with the path helper:

= button_to :tweet, tweet_path(:id => @sponsor.id)

If you don’t want it in the query string:

= form_tag tweet_path do |f|
  = hidden_field_tag :id => @sponsor.id
  = submit_tag "Tweet"

This does the same thing as your button_to, but adds a hidden field to the form that is generated.