How to access form object parameters in active admin - ruby

Question

Really hope this is actually possible but I can't seem to access my forms parameters to send with my custom action
My aim here is for a user to fill in their form, click on a Preview button that will show them what their post will look like, i have created the view which is fine, just passing the parameters is an issue.
This is my current form
# Create Blog Post
form do |f|
inputs 'Blog' do
f.semantic_errors
f.input :title
f.input :category_id, as: :select, collection: Category.all
f.input :comments, as: :text, input_html: { rows: 10, cols: 10 }
f.input :published, as: :boolean
end
inputs 'Submit' do
f.actions do
f.action :submit
f.action :cancel
f.action :reset
li do
link_to 'Preview', preview_my_admin_panel_posts_path(post: { title: "test", comments: 'comments', category_id: '1' }) # Hardcoded for now
end
end
end
end
# Collection Action to handle object
collection_action :preview, method: :get do
#post = Post.new(permitted_params[:post])
end
So with everything the way it is (hardcoded) the params are passed through and output in my preview view, but as soon as i try accessing the forms object/params nothing gets passed th
# Console Output
1 - link_to 'Preview', preview_my_admin_panel_posts_path(post: { title: f.object.title, comments: f.object.comments, category_id: f.object.category_id})
#<Post:0x007f8bbe1fc4c0 id: nil, title: "", comments: "", category_id: nil, slug: nil, published: 0, created_at: nil, updated_at: nil>
2 - link_to 'Preview', preview_my_admin_panel_posts_path(post: { title: f.title, comments: f.comments, category_id: f.category_id })
# Console Output
#<Post:0x007f8bbe1fc4c0 id: nil, title: nil, comments: nil, category_id: nil, slug: nil, published: 0, created_at: nil, updated_at: nil>
3 - link_to 'Preview', preview_my_admin_panel_posts_path(#post)
# Console Output
#<Post:0x007f8bbe1fc4c0 id: nil, title: nil, comments: nil, category_id: nil, slug: nil, published: 0, created_at: nil, updated_at: nil>
Not sure where else to go with this, f.object.param seems close but passing through empty strings? has anyone done this before ?
If anyone has an alternative solution would love to hear it.
Thanks
Update
When outputting params to the console i get this returned
{"action"=>"preview", "controller"=>"my_admin_panel/posts"}

Answer 1

Are you trying to create a post? When you load this page the fields do not have any value thus the link will not load any parameter(you can inspect element on the preview link and see that the link does not have any parameter).
One way is to use JavaScript to catch the value before the link has routed in controller.