I'm using the Rails gem, Public Activity and wanted to create an activity instance for every update action but with a catch. I only want the event created if a certain attribute is changed. In my case it would be a post's time_zone. Here is how activities are currently created in my posts controller:
class PostsController < ApplicationController
def update
...
@post.create_activity :update, owner: current_user
...
end
end
I couldn't find anything in the docs that explain how to do the aforementioned. Is there a way to setup, let's say a conditional that checks if the time_zone has changed to make this happen?
ActiveModel::Dirty handles tracking changes to attributes in your model. There are a number of ways to tell whether or not a specific attribute did change:
changed_attributes returns a Hash of model changes before save (meaning it is {} after a save because you have a clear, unchanged state for the current object). That won't work in your controller.previous_changes returns a Hash of attributes that were changed by a save. This is what you want for your controller.So, you need the following in your controller
def update
@post = Post.find(params[:id])
@post.update!(post_params)
if @post.previous_changes.key?('time_zone')
@post.create_activity(:update, owner: current_user)
end
end