Rails%203%20In%20Action

10.1.2 The comment form
Leaving a comment
Let’s continue building this comment form for the application, the same one to which
you’ll eventually add a state-select box to complete this feature. This comment form
will consist of a single text field in which the user can insert their comment.
Add a single line to the bottom of app/views/tickets/show.html.erb to render the
comment form partial:
This line renders the partial from app/views/comments/_form.html.erb, which you
now create and fill with the content from the following listing.
Listing 10.3 app/views/comments/_form.html.erb
New comment
Pretty much the standard form_for here, except you use the Array-argument syntax
again, which will generate a nested route. You need to do four things before this form
will work.
First, you must define the @comment variable in the show action in Tickets-
Controller so this form_for has something to work with.
Second, you need to create the Comment model and associate this with your Ticket
model so you can create new records from the data in the form and associate it with
the right ticket.
Third, you need to define the nested resource so that the form_for knows to POST
to the correct URL, one similar to /tickets/1/comments. Without this, you run into an
undefined method of ticket_comments_path when the form_for tries to generate
the URL by combining the classes of the objects in the array for its action.
Finally, you need to generate the CommentsController and the create action
along with it so that your form has somewhere to go when a user submits it.
Now set up your TicketsController to use the Comment model for creating new
comments, which you’ll create shortly afterward. To do this, you need to first build a
new Comment object using the comments association on your @ticket object.
10.1.3 The comment model
The first step to getting this feature to pass is to set up the show action in your
TicketsController to define a @comment variable for the comment form. To do this,
change the show action, as shown in the following listing.
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