StickyParams

A little gem that automatically remembers the request parameters between requests without hassle. For example for remembering the filtering and sorting of a list, when switching to a detail screen and back.

class MyController < ApplicationController
  def index
    @order = sticky_params[:order]
    @q  = sticky_params[:q]
  end
end

Release Notes 2.1

Release 2.1.1, Add the method with_prefix, to invoke a block of code with another sticky_params prefix. It also deduplicates code by moving it to the StickyParams::BaseParams class.

Release 2.1, Sticky Params doesn't put ActionController::Parameters in a session anymore. ActionController::Parameters were put directly into a session in 2.0. Which worked in rails < 7. In rails 7 this results in a TypeError (can't dump IO) when the session data is serialized.

Release 2.0, uses ActionController::Parameters instead of hashes. This enable the usage of the strong parameter permit construct. (In other words, sticky_params will work just like normal params)

To get the 1.0 behavior, you can add the following to your ApplicationController.

  def sticky_params
    @sticky_params ||= ::StickyParams::SessionParams.new(self)
  end

Installation

Add this line to your application's Gemfile:

gem 'sticky_params'

And then execute:

bundle

Usage

Just start using it, by simply replacing the normal params call with a sticky_params call:

class MyController < ApplicationController
  def index
    @order = sticky_params[:order]
    @q  = sticky_params[:q]
  end
end

You can also store stuff in the sticky params hash

sticky_params["keyname"] = "value"

Remove sticky stuff

Sticky parameters can be removed one by one, by simply passing a empty string.

sticky_params[:order] = ""  # removes the keyname order from the session

To remove all sticky stuff for the current controller/action you can simply call clear!

sticky_params.clear!

To remove all sticky stuff, for every action/controller you can use clear_all! But probably you don't want this ;)

sticky_params.clear_all!

Inner workings

Sticky params are stored in the session storage. They are stored in a session variable named 'sticky_params'.

This session variable is a hash and it uses a prefix for storing the variables. By default the prefix is "controller_action_"

When retrieving a parameter from sticky_params it first tries to retrieve it from the normal parameters. When it's found in the parameters, it stores the result in the sticky_params storage. If the parameter isn't in the normal aparameters it does a lookup in the session hash. Pretty simple.

Common Pattern

A pattern I used often with sticky_params, is using a request parameter 'reset' .

For example for a basic rest controller, I have an index action which shows all users. The list of users is sortable, searchable and paged. When selecting a user in this table I goto the user screen. When going back I want my selection to persist.

But when I enter the users index screen from my application-menu, I want to reset all my filters. I supply a parameter reset:

link_to("Users", users_path(reset: 1))

Normal links, for example the list button in the user screen

link_to("Users", users_path)

In the controller the index action is implemented like this

class UsersController < ApplicationController
  def index
    sticky_params.clear! if params[:reset]

    @order = sticky_params[:order]
    @page = sticky_params[:page]
    # ... other fancy controller stuf ...
  end
end

For the lazy developers. you could force the reset parameter to always work in your application.

class ApplicationController < ActionController::Base
  before_action :sticky_params_reset

protected:
  def sticky_params_reset
    sticky_params.clear! if params[:reset]
  end
end

have fun ;)