How to realize a share link function

If your app have many objects users want to share with other users, it may be time to think about a share link function. This article shows the way.

Specification

・User have lists about restaurants they like.

・User can create the link for sharing the list with other users(other users are not registered in this app).

・Other users can look at the list without logging in.

Preparation

 class User
   has_many :lists
 end

and

class List
  belongs_to :user
end

coding

Firstly, I created ShareHash object.

class ShareHash < ApplicationRecord
  belongs_to :list
  before_create :create_hash
  private
  def create_hash
    self.assign_attributes(hash_string: Digest::SHA1.hexdigest(Time.now.to_s))
  end
end

By create_hash, it becomes possible to create the share hash itself.

Secondly, it is necessary to remove user authentication when unregistered users reach the link.

class ApplicationController < ActionController::Base
  before_action :authenticate_user!, if: :authenticate?
  
  private
  def authenticate?
    true
  end
end

and

class SharedListsController < ApplicationController
  def show
    @list = ShareHash.find_by(hash_string: params[:hash_string]).list
  end
  private
  def authenticate?
    false
  end
end

Users who are not unregistered can look at the contents of the list.

Finally, we have to set a creating share link button.

<%= link_to 'create the share link', list_share_hashes_path(@list), method: :post %>

It is possible to look at the list by putting the link into a browser.

Started LinkedIn as well!

https://www.linkedin.com/in/tomoharu-tsutsumi-56051a126/