Rails: How to get the model class name based on the controller class name?

class HouseBuyersController < ...
  def my_method
    # How could I get here the relevant model name, i.e. "HouseBuyer" ?
  end
end

This will do it:

class HouseBuyersController < ApplicationController
  
  def index
    @model_name = controller_name.classify
  end

end

This is often needed when abstracting controller actions:

class HouseBuyersController < ApplicationController

  def index
    # Equivalent of @house_buyers = HouseBuyer.find(:all)
    objects = controller_name.classify.constantize.find(:all)
    instance_variable_set("@#{controller_name}", objects)
  end

end

If your controller and model are in the same namespace, then what you want is

controller_path.classify

controller_path gives you the namespace; controller_name doesn't.

For example, if your controller is

Admin::RolesController

then:

controller_path.classify # "Admin::Role" # CORRECT
controller_name.classify # "Role"        # INCORRECT

It's a bit of a hack, but if your model is named after your controller name then:

class HouseBuyersController < ApplicationController
  def my_method
    @model_name = self.class.name.sub("Controller", "").singularize
  end
end

... would give you "HouseBuyer" in your @model_name instance variable.

Again, this makes a huge assumption that "HouseBuyersController" only deals with "HouseBuyer" models.

For namespaces working:

def resource_class
 controller_path.classify.constantize
end

The accepted solution did not work for me as my controller and model was namespaced. Instead, I came up with the following method:

def controllers_model
  (self.class.name.split('::')[0..-2] << controller_name.classify).join('::')
end

This is not possible if you are using the default MVC, which your code doesn't seem to follow. Your controller seems to be a model but maybe you just got a type there. Anyway, controllers and models are fundamentally separated in Rails MVC so controllers cannot know which model they are associated with.

For example you could have a model named post. This can have a controller posts_controller or could have a controller like articles_controller. Rails only knows about models when you def the actual code in the controller such as

def index
  @posts = Post.all
  @posts = Article.all
end  

In rails standard controllers there is no way to know what the model is.