Action Controller exception undefined method `merge' for xxx:String - ruby-on-rails

Question

I'm doing simple Reddit like site. I'm trying to add button to reporting posts. I create report model, using button_to i try to post data to report controller to create it but i received NoMethodError in ReportsController#create undefined method merge' for "post_id":String
model/report.rb
class Report < ApplicationRecord
belongs_to :reporting_user, class_name: 'Author'
has_one :post
end
report_controller.rb
class ReportsController < ApplicationController
def create
report = Report.new(report_params)
flash[:notice] = if report.save
'Raported'
else
report.errors.full_messages.join('. ')
end
end
def report_params
params.require(:post).merge(reporting_user: current_author.id)
end
end
and button in view
= button_to "Report", reports_path, method: :post, params: {post: post}
What cause that problem?
edit:
params
=> <ActionController::Parameters {"authenticity_token"=>"sX0DQfM0rp97q8i16LGZfXPoSJNx15Hk4mmP35uFVh52bzVa30ei/Bxk/Bm40gnFmd2NvFEqj+Wze8ted66kig==", "post"=>"1", "controller"=>"reports", "action"=>"create"} permitted: false>

Answer 1

To start with you want to use belongs_to and not has_one.
class Report < ApplicationRecord
belongs_to :reporting_user, class_name: 'Author'
belongs_to :post
end
This correctly places the post_id foreign key column on reports. Using has_one places the fk column on posts which won't work.
And a generally superior solution would be to make reports a nested resource:
# /config/routes.rb
resources :posts do
resources :reports, only: [:create]
end
# app/controller/reports_controller.rb
class ReportsController
before_action :set_post
# POST /posts/:post_id/reports
def create
#report = #post.reports.new(reporting_user: current_author)
if #report.save
flash[:notice] = 'Reported'
else
flash[:notice] = report.errors.full_messages.join('. ')
end
redirect_to #post
end
private
def set_post
#post = Post.find(params[:post_id])
end
end
This lets you simplify the button to just:
= button_to "Report", post_reports_path(post), method: :post
Since the post_id is part of the path we don't need to send any additional params.
If you do want to let the user pass additional info through a form in the future a better way to create/update resources with params and session data is by passing a block:
#report = #post.reports.new(report_params) do |r|
r.reporting_user = current_user
end

Answer 2

ActionController::Parameters#require returns the value of the required key in the params. Usually this would be an object passed back from a form. In this example require would return {name: "Francesco", age: 22, role: "admin"} and merge would work.
Your view is sending back parameters that Rails is formatting into {post: 'string'}. We would need to see your view code to determine what exactly needs to change.
Update: From the new code posted we can see that the parameter sent back is "post"=>"1". Normally we would be expecting post: {id: 1, ...}.
Update: The button in the view would need the params key updated to something ala params: {post: {id: post.id}} EDIT: I agree that params: {report: { post_id: post}} is a better format.

Answer 3

The problem seems to be in report_params. When you call params.require(:post), it fetches :post from params -> the result is string. And you are calling merge on this string.
I'd recommend change in view:
= button_to "Report", reports_path, method: :post, params: { report: { post_id: post} }
then in controller:
def report_params
params.require(:report).permit(:post_id).merge(reporting_user_id: current_author.id)
end
Note, that I changed also the naming according to conventions: model_id for id of the model, model or model itself.