Question

Useful additional info: I am using the decent_exposure gem so this might be the issue – correcting the code below:

expose(:get_filter_tags) do
  if params[:filter_tag_names]
    filter_tag_names = Array(params[:filter_tag_names].split(" "))
    filter_tags = Array.new
    filter_tag_names.each do |f|
      t = Tag.find_by_name(f)
      filter_tags << t
    end 
  end
end

So, something funny happens when I call this in the view:

query string ?utf8=✓&filter_tag_names=test

<% get_filter_tags.each do |ft| %>
  <%= ft.name %> 
<% end %>

Error message: undefined method `name’ for “test”:String

Why is this trying to call name on a string not a Tag object? If I put the following in the view, and have jut one filter_tag_names item

def getfiltertag
  Tag.find_by_name(params[:filter_tag_names]) 
end

#view
<%= getfiltertag.name %>

query string: ?utf8=✓&filter=test

like above then I can call name just fine, so obviously I am doing something wrong to get an array of strings instead of objects. I just don’t know what. Any suggestions?

Answer 1

Your problem is that each returns self — so if you write filter_tag_names.each, it returns filter_tag_names. You could fix this by explicitly returning filter_tags, but more idiomatically, you could just rewrite it as:

expose(:get_filter_tags) do
  if params[:filter_tag_names]
    filter_tag_names = Array(params[:filter_tag_names].split(" "))
    filter_tag_names.map {|f| Tag.find_by_name(f) } 
  end
end

Just as an aside, this method will return nil if there aren’t any filter tag names. You may want to do that, or you might want to return an empty collection to avoid exceptions in the calling code.