codesnips

activerecord

ruby 
class CreateAuditLogs < ActiveRecord::Migration[7.1]
  def change
    create_table :audit_logs do |t|
      t.references :auditable, polymorphic: true, null: false
      t.string :actor
      t.string :action, null: false

Audit Trail with JSON Diff (Minimal, Useful)

rails activerecord auditing
by codesnips 4 tabs
ruby 
class AddCommentsCountToPosts < ActiveRecord::Migration[6.1]
  def up
    add_column :posts, :comments_count, :integer, default: 0, null: false

    # Populate existing counts
    Post.find_each do |post|

Counter cache for association counts

rails performance activerecord
by Alex Kumar 2 tabs
ruby 
class DailySignupRollup < ApplicationRecord
  validates :day, presence: true, uniqueness: true
  validates :total, :verified, numericality: { greater_than_or_equal_to: 0 }

  scope :for_range, ->(from, to) do
    where(day: from.to_date..to.to_date).order(:day)

Nightly Signup Rollups in Rails with a Scheduled Job and Upsert

rails postgres background-jobs
by codesnips 3 tabs
ruby 
class ReportsController < ApplicationController
  def monthly_sales
    year = params.fetch(:year, Date.current.year).to_i
    rows = Order.monthly_sales(year: year)
    @report = MonthlySalesReport.new(rows, year: year)

Aggregate Monthly Sales Reports in Rails with group_by SQL and a Presenter

rails postgres reporting
by codesnips 3 tabs
ruby 
class ApplicationPolicy
  attr_reader :user, :record

  def initialize(user, record)
    @user = user
    @record = record

Enforcing Controller Authorization with a Pundit-Style Policy Object in Rails

rails authorization pundit
by codesnips 4 tabs
ruby 
class User < ApplicationRecord
  has_many :posts, foreign_key: :author_id

  validates :email, presence: true,
                    uniqueness: { case_sensitive: false },
                    format: { with: URI::MailTo::EMAIL_REGEXP }

Model validations for data integrity

rails activerecord validation
by Alex Kumar 1 tab
ruby 
module KeysetPaginatable
  extend ActiveSupport::Concern

  class_methods do
    def keyset_page(cursor: nil, limit: 20, direction: :desc)
      limit = limit.to_i.clamp(1, 100)

Keyset Cursor Pagination for ActiveRecord Instead of OFFSET

ruby rails activerecord
by codesnips 4 tabs
ruby 
class PopularPostsQuery
  def initialize(relation = Post.all)
    @relation = relation
  end

  def call(timeframe: 7.days, min_views: 100, limit: 20)

Query objects for complex ActiveRecord queries

rails activerecord patterns
by Alex Kumar 2 tabs
ruby 
class Product < ApplicationRecord
  scope :by_status, ->(status) {
    status.present? ? where(status: status) : all
  }

  scope :in_category, ->(category_id) {

Composable Query Filters with Rails Scopes and a Filter Object

rails activerecord scopes
by codesnips 3 tabs
ruby 
class ImportResult
  RowError = Struct.new(:line, :messages)

  attr_reader :imported, :row_errors

  def initialize

Streaming CSV Product Import With Per-Row Validation and Error Reporting in Rails

rails csv service-object
by codesnips 3 tabs
ruby 
class PriceBreakdown < Struct.new(:subtotal_cents, :discount_cents, :tax_cents, keyword_init: true)
  def initialize(*)
    super
    freeze
  end

Memoizing a Pricing Breakdown as an Immutable Value Object in Rails

rails memoization value-object
by codesnips 3 tabs
ruby 
class LastSeenTracker
  THROTTLE = 5.minutes
  PENDING_KEY = "pending:last_seen".freeze

  class << self
    def touch(user_id, at: Time.current)

Database “Last Seen” without Hot Row Updates

rails performance redis
by codesnips 3 tabs