Rails tuples

_rails-tuples-readme.md

Rails tuples

Simple key-value storage with data types and expiration control.

db__migrate__create_tuples.rb

class CreateTuples < ActiveRecord::Migration[7.0]
  def change
    create_table :tuples do |t|
      t.string :key, index: { unique: true }

      t.jsonb :data, default: {}
      t.integer :datatype
      t.datetime :expires_at

      t.timestamps
    end
  end
end

models__tuple.rb

class Tuple < ApplicationRecord
  validates :key, presence: true, uniqueness: true
  validates :datatype, presence: true

  enum datatype: {
    Integer: 10,
    String: 20,
    Hash: 30
  }, _prefix: true

  def self.get(key)
    record = find_by(key:)
    return if record.blank?
    return if record.expired?

    record.value
  end

  def self.set(key, value = nil, expires_in: nil, &block)
    upsert_all([{
      key:,
      value: value || block&.call,
      expires_at: (expires_in.since if expires_in.present?)
    }], unique_by: "key")
  end

  def self.reset(key)
    where(key:).delete_all
  end

  def self.fetch(key, value = nil, expires_in: nil, &block)
    record = where(key:).first_or_initialize
    if !record.persisted? || record.expired?
      record.update!({
        value: value || block&.call,
        expires_at: (expires_in.since if expires_in.present?)
      })
    end
    record.value
  end

  def self.increment(key, amount = 1, expires_in: nil)
    where(key:, datatype: :Integer).update_all("data = to_jsonb((data::integer) + #{amount.to_i})")
  end

  def expired?
    expires_at.present? && expires_at.past?
  end

  def value
    case datatype
    when "Integer"
      data.to_i
    when "String"
      data.to_s
    when "Hash"
      data
    else
      raise "Invalid data type"
    end
  end

  def value=(new_value)
    self.data = new_value
    self.datatype = data.class.name
  end
end