在Rails中使用强参数动态生成方法

Question

Is it possible to generate a dynamic method using the strong parameter I get from my view?

In my view I will generate a different path according to the card the user clicks on. Then, in the controller I want to generate a dynamic method using the parameter obtained from the view, but I'm not sure how to write that. Thanks!

show.html.erb

<div class="branch-names">
  <% @branches.each do |branch| %>
    <div>
     <%= image_tag "cat.jpeg" %>
     <%= link_to "#{branch.name} Posts", send("#{branch.branch}_posts_path") %>
   </div>
  <% end %>
</div>


posts_controller.rb

def self.define_category(name)
 define_method(name) do |params[:id]|
  @posts = Post.where(category_id = params[:id])
 end
end


define_category("#{params[:id]}")

Answer 1

You shouldn't define method based on user input. It may cause security issue, and for sure it causes performance penalty related to method cache invalidation .

Instead you can create one method that have an alternarive on params[:id] and then decide what to show to the user:

class MyController
  def branches
    case params[:id]
    when('cat')
      do_cat_stuff
    when('dog')
     do_dog_stuff
    end
  end
end

Answer 2

For having routes like /posts/cats you do not have to add dynamic methods. Think of branch like of an id of category:

routes:

resources :post_categories, only:[:index, :show]

view:

...
<%= link_to "#{branch.name} Posts", post_category_path(branch.branch) %>

PostCategories controller:

def show
  @posts = Post.where(category_id: params[:id])
end

Also you can make posts a nested resource under categories and use a more RESTful structure with /post_categories/some_branch/posts mapping to posts#index