[Rails] Notification function

Development environment

• ruby 2.6.3
• rails 6.0.2

Synopsis

• Through [Optional Exercise 1: Issue to issue an alert when there is a task that is about to end or has passed the deadline].
• We will introduce a mechanism to notify you when the expiration date has expired or just before the expiration date.

Create a notification model

Terminal

rails g model notification user:references task:references action:integer checked:boolean

db/migrate

class CreateNotifications < ActiveRecord::Migration[6.0]
  def change
    create_table :notifications do |t|
      t.references :task, null: false, foreign_key: true
      t.references :user, null: false, foreign_key: true
      t.integer :action
      t.boolean :checked, default: false, null: false

      t.timestamps
    end
  end
end

• Classify notification types with action, and identify unread and read with checked.

Terminal

rails db:migrate

Various models

• The task and notification are 1 to 1 because the notification is issued when the task deadline is approaching or has passed.

User model

app/models/user.rb

class User < ApplicationRecord
  has_many :notifications, dependent: :destroy
end

Task model

app/models/task.rb

class Task < ApplicationRecord
  belongs_to :user
  has_one :notification, dependent: :destroy
end

Notification model

app/models/ntification.rb

class Notification < ApplicationRecord
  default_scope->{order(created_at: :desc)}

  belongs_to :task
  belongs_to :user

  enum action: { warning: 1, expired: 2}
end

What is an enum

• [Rails] What kind of child is Enum? Can you use it?

enum column name: {Name definition:Numerical value}
It is an enumeration type, and when actually registering, save the name definition.

view side

• Only index, as long as you can check the list.

python

rails g controller notifications index

config/routes.rb

Rails.application.routes.draw do
  resources :notifications,only: [:index]
end

app/controllers/notifications_controller.rb

class NotificationsController < ApplicationController
  def index
    @notifications = current_user.notifications
    @notifications.where(checked: false).each do |notification|
      notification.update(checked: true)
    end
  end
end

• Access the index to mark it as read.

Notify unread and read notifications

ruby:app/views/layouts/_header.html.slim

- if unchecked_notifications.any?
  p.text-danger ★
= link_to "notification",notifications_path, class: 'nav-link'

app/helpers/notifications_heler.rb

module NotificationsHelper
  def unchecked_notifications
    @notifications = current_user.notifications.where(checked: false)
  end
end

app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  include NotificationsHelper
end

Create a rake task to run on a regular basis

• [Ruby on Rails] Can various processes be automated by using Rake task? (For beginners)

What is Rake
Rake is a function that allows you to create code written in Ruby as a task and call and execute it as needed.

Here are some situations where you can use the rake task.

Linkage of some kind of data
Database backup
Update and delete data on a regular basis

As for adding a path to be autoloaded did not work, I write it directly in the rake file.

• Create Rake task in Rails

python

rails g task notification
rails g task filename

• From today's date, create a DB with each deadline.

lib/tasks/notification.rake

namespace :task do
  desc "notification/Move once a day."
  task :notification => :environment do
    today = Date.today
    tasks = Task.all
    n = tasks.count
    today = Date.today
    tasks.each do |task|
      user = task.user
      if today + 1 == task.deadline.to_date
        Notification.create(task_id: task.id, user_id: user.id, action: "warning")
      end
      if task.notification.nil? && today > task.deadline.to_date
        Notification.create(task_id: task.id, user_id: user.id, action: "expired")
      elsif task.notification.present? && today > task.deadline.to_date
        task.notification.update(action: "expired")
      end
      n -= 1
      puts "remaining#{n}/#{tasks.count}"
    end
  end
end

Run

rake tasks:notification
rake [name of namespece]:[task name]

For the production environment

In my case, it's heroku, so it seems to use heroku scheduler. I will summarize it again. gem: whenever is a gem that has been added / rewritten to crontab.

• WHENEVER didn't work on HEROKU because I misunderstood

[Addition] Introduced heroku scheduler

• Heroku Scheduler
  1.heroku addons:add scheduler:standard

2. Set the time and task you want to run on Heroku Scheduler

heroku run rake task:notification