为什么我不需要将参数传递给 article_params？

Question

How does the article_params method get access to params without it being passed as a parameter? Thanks in advance.

class ArticlesController < ApplicationController
  private def article_params
    params.require(:article).permit(:title, :text)
  end
  def create
    @article = Article.new(article_params)

    if @article.save
      redirect_to @article
    else
      render 'new'
    end
  end

Answer 1

Because params is not a variable, it's a method in ActionController::Base which returns the parameters passed in by the call, and, being a method, is available to be called by any method in any controller. In fact you can reference params in views, so it's not only a method, it's a helper method.

As described in https://api.rubyonrails.org/classes/ActionController/Base.html

All request parameters, whether they come from a query string in the URL or form data submitted through a POST request are available through the params method which returns a hash.