Ok I am making a JQuery .post request to a server to insert some data. It only works sometimes depending on what methods are in the Rails create method.
Here are the specifics. I have a Rails app with Backbone.js on the frontend. In my frontend code I make this .post request
$.post('/publications');
Seems simple enough. I have a Publication model as well as
resources :publications
in the router. Now in my Publications controller I augmented the create method to the following:
def create
feed = Feedzirra::Feed.fetch_and_parse(publication_params[:url])
params = {:name => feed.title}
@publication = Publication.new(params)
respond_to do |format|
if @publication.save
format.html { redirect_to @publication, notice: 'Publication was successfully created.' }
format.json { render action: 'show', status: :created, location: @publication }
else
format.html { render action: 'new' }
format.json { render json: @publication.errors, status: :unprocessable_entity }
end
end
end
Feedzirra is a gem that parses RSS feeds. When I make the POST request like this I get a 500 (Internal Server Error) and this message from my server logs
NoMethodError (undefined method `title' for {}:Hash):
app/controllers/publications_controller.rb:28:in `create'
Rendered /Users/ericabt1/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_source.erb (40.3ms)
Rendered /Users/ericabt1/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.1ms)
Rendered /Users/ericabt1/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.0ms)
Rendered /Users/ericabt1/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (54.7ms)
What is confusing me is that if I choose a different method than 'title' like 'entries' or 'nil?' the POST request works just fine. I know that 'title' is indeed a method because when I go into Rails console and create a test Feedzirra object and look at the various methods available I see that 'title' is one of them.
Why does my POST request work for some of these method but not others?!?!?!?!
* UPDATE ****
After taking krabbi and Alexander Zolotko's advice I started playing with what FeedZirra is returning. It looks like the line
feed = Feedzirra::Feed.fetch_and_parse(publication_params[:url])
is returning an empty hash.
Now when I run the same line in the rails console and hardcode a url in there it returns the proper hash and I am able to grab the title and other values. So it looks like the issue lies with
publication_params[:url]
Still working on this and open to suggestions:)
* UPDATE PART TWO *
I thought the problem was that there was no url column in the Publication Model. So I made the proper migration. So here is the schema:
create_table "publications", force: true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
t.string "url"
end
Back to the controller I have at the bottom:
private
# Use callbacks to share common setup or constraints between actions.
def set_publication
@publication = Publication.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def publication_params
params.permit(:name, :url)
end
publication_params[:url] is still returning nil. I have also tried the line:
params.require(:publication).permit(:url, :name)
which just gives me 400 Bad request error
As Alexander Zolotko points out Feedzirra::Feed.fetch_and_parse
seems to return a hash.
Try for example
params = { :name => feed[:title] }
Assuming frontend is correct and REST resource publications is properly set up in Rails backend.
Controller should for example look like:
def create
# requesting the feed from passed url
feed = Feedzirra::Feed.fetch_and_parse(publication_params[:url])
# mapping feed keys to publication attributes
feed_to_publication_hash = { :name => feed[:title], anything else }
# instantiating new publication
@publication = Publication.new(publication_params.merge(feed_to_publication_hash))
...
end
private
def publication_params
params.require(:publication).permit(:url, everything else you need)
end
I am quite sure that even if that works it is not good practice. Usually you strife for Object Orientation, that is in this case one purpose per action.
But I don't know right now how to refactor fetching the feed and perhaps mapping the hash. Maybe it is a controller concern or something like that.