Creating an object from the show action of another object in Rails - ruby-on-rails

Question

So I have a fairly typical blog application with posts and comments.
Each comment belongs to one post
A post can have many comments.
Basically I want to add a form for comments to the show action for posts, without having post_id under attr_accessible in the comment model.
In my posts controller I have:
def show
#post = Post.find(params[:id])
#poster = "#{current_user.name} #{current_user.surname} (#{current_user.email})"
#comment = #post.comments.build( poster: #poster )
end
I'm not entirely sure what I should be doing in the comments controller (I'm not confident that the code above is right either if I'm honest). At the moment I have:
def create
#post = Post.find(params[:post_id])
#comment = #post.comments.build(params[:post])
if #comment.save
redirect_to #post, notice: "Comment posted"
else
redirect_to #post, error: "Error!"
end
end
My routes:
resources :comments
resources :posts do
resources :comments
end
and finally the form:
<%= form_for #post.comments.build do |f| %>
<%= f.label :content, "WRITE COMMENT" %>
<%= f.text_area :content, rows: 3 %>
<%= f.hidden_field :post_id, value: #post.id %>
<%= f.submit "Post" %>
<% end %>
The problem here is that I have no way of passing my post_id from the show action of the posts controller to the create action of the comments controller. Any help is much appreciated. Thank you in advance!

Answer 1

Your posts controller looks fine... but assuming your routes looks like
resources :posts do
resources :comments
end
then your CommentsController#create should/could look like:
def create
#post = Post.find(params[:post_id])
#comment = #post.comments.build(params[:comment])
if #comment.save
redirect_to #post, notice: "Comment posted"
else
redirect_to #post, error: "Error!"
end
end
And your form:
<%= form_for [#post, #comment] do |f| %>
<%= f.hidden_field :poster, value: #poster %>
<%= f.label :content, "WRITE COMMENT" %>
<%= f.text_area :content, rows: 3 %>
<%= f.submit "Post" %>
<% end %>

Answer 2

I will assume that your post model has_many comments and comment belongs_to post
than you in your routes file you can do something like this
resources :posts do
resources :comments
end
this will give you a url schem such as
/posts/:post_id/comments , allowing you to always have post_id of the comment parrent

Answer 3

The URL for your show post should be like post/show/(:id).
Now, in the comment form, you can place a hidden field, with value of params[:id].
hidden_field(:post_id, :value => params[:id])
When you submit your form, you can get the value of post_id using the hidden field.
def create
#comment = Comment.new(params[:comment])
#comment.post_id = params[:post_id]
if #comment.save
flash[:notice] = 'Comment posted.'
redirect_to post_path(#comment.post_id)
else
flash[:notice] = "Error!"
redirect_to post_path(#comment.post_id)
end
end