Ruby on Rails：将控制器中的请求参数传递给模型的after_create事件

Question

I have two models:

1) Procedure
     title
     document_number

2) Revision
     revision_number

In my procedure model, I defined a method after_create to automatically create a Revision with revision_number set to 0.1.

# app/models/procedure.rb

# How do I get revision_number from the request params in this method?
after_create do |procedure|
    procedure.revisions.create(revision_number: 0.1)
end

That works well, however, I do not want to always default to 0.1 - For example, if I want to specify a revision number from parameters sent in the form request to the controller, I am a bit lost there. I looked throughout the guides and I wasn't able to find a way to pass data into the create event. This is my method in my controller:

# app/controllers/procedures_controller.rb

def create
    @procedure = current_user.procedures.build(procedure_params)

    if @procedure.save
        render json: @procedure, status: :created, location: @procedure
    else
        render json: @procedure.errors, status: :unprocessable_entity
    end
end

def procedure_params
    params.require(:procedure).permit(:title, :document_number, :revision_number)
end

The only way I can think of accomplishing this is by adding a column 'revision_number' to my procedure model, and then checking whether it is set in my 'after_create' method.

I would appreciate any other suggestions for how I might be able to tackle this problem. Or if there is already a way and I missed it in the guides, I would appreciate a reference to that section. Thanks!

Answer 1

you are trying to violate MVC architecture and Single Responsiblity Principle . Controller is responsible for handling HTTP request and Model is responsible for interacting with database.

In any case you commited to violate rules :-

class Procedure < ActiveRecord::Base
  def add_revision_number(number)
    self.revision_number = number
  end
end

class ProceduresController < ApplicationController
  def create
    ...
    @procedure.add_revision_number(params[:revision_number])
    ...
  end
end

now access revision_number in model

I prefer not to pass controller request object directly. It Isolates model from current request.

Answer 2

app/models/procedure.rb

attr_accessor :revision_no

after_create do |procedure|
    procedure.revisions.create(revision_number: self.revision_no)
end

Now you can pass value in revision_no.