moro

Event is what happens — トークスクリプト

Kaigi on Rails 2026(2026-10-16)諸橋恭介 @moro

公開スライドの各ページに対応するトークスクリプトです。見出しのページ番号はスライドのページ番号に対応しています。

元のスライドはこちら。 https://speakerdeck.com/moro/event-is-what-happens

---

moro

require 'csv'
require 'sequel'

def sql_to_csv(sql, db: Sequel.connect(ENV['DATABASE_URL']))
  rel = db[sql]

  CSV.generate('', force_quotes: ENV['NO_QUOTE'].nil?) do |csv|
    csv << rel.columns
    rel.each {|row| csv << row.values }
  end

moro

module Constructor
  def constructor(*names)
    define_method(:initialize) do |*args|
      names.zip(args).each do |name, value|
        instance_variable_set("@#{name}", value)
      end
    end
  end
end

moro

class Foo < ActiveRecord::Base
  after_save :do_something, unless: :other_situation?

  class << self
    def other_situation
      begin
        Thread.current[:other_situation] = true
        yield
      ensure
        Thread.current[:other_situation] = nil

moro

module Doublet
  def doublet(name, &block)
    let(name) { double.tap(&block) }
  end

  def doublet!(name, &block)
    let!(name) { double.tap(&block) }
  end
end

moro

module CoffeeConstructor
  def constructor(*ivars)
    define_method :initialize do |*args|
      raise(ArgumentError) unless ivars.size == args.size

      ivars.zip(args).each do |ivar, val|
        instance_variable_set(ivar, val)
      end
    end
  end

moro

module Censorable
  extend ActiveSupport::Concern

  class MonitorRequestFailed < RuntimeError
    ...
  end

  included do
    has_many    :monitor_requests, as: :entity, dependent: :destroy

moro

module Retriable
  class RepeatedError < RuntimeError
    def initialize(max, *args)
      @errors = []
      @max    = max
      super(*args)
    end

    def <<(e)
      @errors << e

moro

['foo', 'bar'].inject(Paste.scoped) {|rel, tag|
  rel.where(id: Tagging.joins(:tag).select(:paste_id).where('tags.name = ?', tag))
}.to_sql

# =>
#   SELECT "pastes".*
#   FROM "pastes"
#   WHERE "pastes"."id" IN (SELECT paste_id FROM "taggings" INNER JOIN "tags" ON "tags"."id" = "taggings"."tag_id" WHERE (tags.name = 'foo'))
#     AND "pastes"."id" IN (SELECT paste_id FROM "taggings" INNER JOIN "tags" ON "tags"."id" = "taggings"."tag_id" WHERE (tags.name = 'bar'))
# 

moro

class A
  def foo(num)
    %w[one two three][num - 1]
  end
end

describe A do
  describe "#foo" do
    RSpec::Matchers.define :do_foo do |args|
      match do |instance|