ruby erb 43 lines · 2 tabs

Rails Flash messages for user feedback

Maya Patel Jan 2026

2 tabs

class PostsController < ApplicationController
  def create
    @post = current_user.posts.build(post_params)

    if @post.save
      flash[:success] = 'Post was successfully created.'
      redirect_to @post
    else
      flash.now[:alert] = 'Failed to create post.'
      render :new, status: :unprocessable_entity
    end
  end

  def destroy
    @post = current_user.posts.find(params[:id])
    @post.destroy

    respond_to do |format|
      format.html do
        flash[:notice] = 'Post was successfully deleted.'
        redirect_to posts_url
      end
      format.json do
        render json: { message: 'Post was successfully deleted.' }, status: :ok
      end
    end
  end
end

<!DOCTYPE html>
<html>
  <head>
    <title>My App</title>
  </head>
  <body>
    <% flash.each do |type, message| %>
      <div class="alert alert-<%= type %>">
        <%= message %>
      </div>
    <% end %>

    <%= yield %>
  </body>
</html>

2 files · ruby, erb Explain with highlit

Flash messages provide one-time notifications across requests, perfect for confirming actions or showing errors. I use flash[:notice] for success messages and flash[:alert] for errors. Flash persists in session storage for one request, then auto-deletes. For AJAX requests, I return flash messages in JSON responses since redirects don't happen. The flash hash supports any keys—I add :warning and :success for semantic variety. Flash messages display in layouts, typically near the top of pages. For APIs serving React, I skip flash entirely and send messages in response bodies. Flash works beautifully for traditional request/response but needs adaptation for SPAs.

Related snips

ruby

class CommentsController < ApplicationController
  before_action :set_post

  def create
    @comment = @post.comments.build(comment_params)

System test: asserting Turbo Stream responses

rails hotwire turbo

by codesnips 4 tabs

ruby

class Post < ApplicationRecord
  belongs_to :author, class_name: 'User'
  has_many :comments, dependent: :destroy

  scope :published, -> { where.not(published_at: nil).where('published_at <= ?', Time.current) }
  scope :draft, -> { where(published_at: nil) }

ActiveRecord scopes for reusable query logic

rails activerecord patterns

by Alex Kumar 1 tab

ruby

module Api
  module V1
    class UsersController < BaseController
      def show
        user = User.includes(:profile).find(params[:id])

ETags for conditional requests and caching

rails caching http-caching

by Alex Kumar 1 tab

ruby

class PostsController < ApplicationController
  def index
    @posts = Post.includes(:author)
                 .order(created_at: :desc)
                 .page(params[:page])
                 .per(10)

Turbo Frames: infinite scroll with lazy-loading frame

rails turbo hotwire

by codesnips 4 tabs

ruby

require "csv"

class PeopleCsvStream
  include Enumerable

  HEADERS = %w[id full_name email signed_up_at plan].freeze

Resilient CSV Export as a Streamed Response

rails performance streaming

by codesnips 3 tabs

erb

<form data-controller="query-sync" data-action="change->query-sync#apply">
  <select name="status" class="rounded border p-2">
    <option value="">Any</option>
    <option value="open">Open</option>
    <option value="closed">Closed</option>
  </select>

Filter UI that syncs query params via Stimulus (no front-end router)

rails hotwire stimulus

by Henry Kim 2 tabs

Share this code

Here's the card — post it anywhere.

Rails Flash messages for user feedback — share card

Link copied