bastos Hotwire for Rails 7+
Comprehensive guide to building modern, reactive web applications with Hotwire (Turbo + Stimulus) in Rails 7+.
What is Hotwire?
Hotwire enables "fast, modern, progressively enhanced web applications without using much JavaScript." It sends HTML over the wire instead of JSON, keeping business logic on the server.
Three components:
- Turbo Drive - Accelerates navigation by intercepting clicks and replacing
<body> - Turbo Frames - Decompose pages into independently-updatable sections
- Turbo Streams - Deliver live partial page updates via WebSocket, SSE, or HTTP
- Stimulus - Modest JavaScript framework for behavior
Turbo Drive
Turbo Drive intercepts link clicks and form submissions, fetching via fetch and replacing <body> while merging <head>. The window, document, and <html> persist across navigations.
Disabling for Specific Elements
<%# Disable Turbo for external links or file downloads %>
<%= link_to "Download PDF", pdf_path, data: { turbo: false } %>
<%# Disable for forms that need full page reload %>
<%= form_with model: @export, data: { turbo: false } do |f| %>
Progress Bar
.turbo-progress-bar {
background-color: #3b82f6;
height: 3px;
}
Turbo Frames
Frames wrap page segments in <turbo-frame> elements for scoped navigation. Only matching frames extract from server responses.
Frame Attributes
| Attribute | Purpose |
|---|---|
id |
Required. Unique identifier to match frames between requests |
src |
URL for eager-loading frame content on page load |
loading="lazy" |
Delay loading until frame becomes visible |
target |
Navigation scope: _top (full page), _self, or frame ID |
data-turbo-action |
Promote to browser history (advance or replace) |
Basic Frame
<%# app/views/articles/show.html.erb %>
<h1><%= @article.title %></h1>
<%= turbo_frame_tag @article do %>
<p><%= @article.body %></p>
<%= link_to "Edit", edit_article_path(@article) %>
<% end %>
<%# app/views/articles/edit.html.erb %>
<%= turbo_frame_tag @article do %>
<%= render "form", article: @article %>
<% end %>
Lazy Loading
<%# Load content when frame becomes visible %>
<%= turbo_frame_tag "comments",
src: article_comments_path(@article),
loading: :lazy do %>
<p>Loading comments...</p>
<% end %>
Breaking Out of Frames
<%# Navigate entire page %>
<%= link_to "View Full", article_path(@article), data: { turbo_frame: "_top" } %>
<%# Target different frame %>
<%= link_to "Preview", preview_path(@article), data: { turbo_frame: "preview_panel" } %>
Frame State Attributes
During navigation, frames receive [aria-busy="true"]. After completion, [complete] is set on the frame.
Turbo Streams
Streams deliver DOM changes as <turbo-stream> elements specifying action and target.
Stream Actions (9 total)
| Action | Description |
|---|---|
append |
Add content to end of target |
prepend |
Add content to start of target |
replace |
Replace entire target element |
update |
Replace target's inner content only |
remove |
Delete target element |
before |
Insert before target element |
after |
Insert after target element |
morph |
Intelligently morph changes (variant of replace/update) |
refresh |
Refresh page or frame |
HTTP Stream Response
# app/controllers/comments_controller.rb
def create
@comment = @article.comments.build(comment_params)
if @comment.save
respond_to do |format|
format.turbo_stream # Renders create.turbo_stream.erb
format.html { redirect_to @article }
end
else
render :new, status: :unprocessable_entity
end
end
<%# app/views/comments/create.turbo_stream.erb %>
<%= turbo_stream.append "comments", @comment %>
<%= turbo_stream.update "comment_count", @article.comments.count %>
<%= turbo_stream.replace "new_comment", partial: "form", locals: { comment: Comment.new } %>
Inline Stream Response
def destroy
@comment.destroy
respond_to do |format|
format.turbo_stream do
render turbo_stream: [
turbo_stream.remove(@comment),
turbo_stream.update("comment_count", @article.comments.count)
]
end
format.html { redirect_to @article }
end
end
Broadcasting via WebSocket
# app/models/comment.rb
class Comment < ApplicationRecord
belongs_to :article
after_create_commit -> {
broadcast_append_to article, target: "comments"
}
after_destroy_commit -> {
broadcast_remove_to article
}
end
<%# Subscribe to broadcasts %>
<%= turbo_stream_from @article %>
<div id="comments">
<%= render @article.comments %>
</div>
WebSocket/SSE Source
<%# Persistent connection for real-time updates %>
<turbo-stream-source src="ws://example.com/updates"></turbo-stream-source>
Stimulus
Stimulus is "a JavaScript framework with modest ambitions." It enhances server-rendered HTML using data attributes.
Controller Structure
// app/javascript/controllers/hello_controller.js
import { Controller } from "@hotwired/stimulus"
export default class extends Controller {
static targets = ["name", "output"]
static values = { greeting: { type: String, default: "Hello" } }
static classes = ["active"]
connect() {
// Called when controller connects to DOM
}
disconnect() {
// Called when controller disconnects - clean up here
}
greet() {
this.outputTarget.textContent = `${this.greetingValue}, ${this.nameTarget.value}!`
}
}
Naming Conventions
| Context | Convention | Example |
|---|---|---|
| Controller file | snake_case or kebab-case | hello_controller.js, date-picker_controller.js |
| Controller identifier | kebab-case in HTML | data-controller="date-picker" |
| Targets | camelCase | static targets = ["firstName"] |
| Values | camelCase | static values = { itemCount: Number } |
| Methods | camelCase | submitForm() |
Targets
Define elements to reference within controller:
static targets = ["query", "results", "errorMessage"]
Generated properties:
| Property | Purpose |
|---|---|
this.queryTarget |
First matching element (throws if missing) |
this.queryTargets |
Array of all matching elements |
this.hasQueryTarget |
Boolean existence check |
Target callbacks:
queryTargetConnected(element) {
// Called when target is added to DOM
}
queryTargetDisconnected(element) {
// Called when target is removed from DOM
}
<div data-controller="search">
<input data-search-target="query">
<div data-search-target="results"></div>
</div>
Values
Read/write typed data attributes:
static values = {
index: Number, // data-controller-index-value
url: String, // data-controller-url-value
active: Boolean, // data-controller-active-value
items: Array, // data-controller-items-value (JSON)
config: Object // data-controller-config-value (JSON)
}
Five supported types: Array, Boolean, Number, Object, String
Default values:
static values = {
count: { type: Number, default: 0 },
url: { type: String, default: "/api" }
}
Change callbacks:
countValueChanged(value, previousValue) {
// Called on initialize and when value changes
this.element.textContent = value
}
Actions
Connect DOM events to controller methods:
Format: event->controller#method
<button data-action="click->gallery#next">Next</button>
Event shorthand (common defaults):
<button>,<a>→click<form>→submit<input>,<textarea>→input<select>→change<details>→toggle
<%# Equivalent to click->gallery#next %>
<button data-action="gallery#next">Next</button>
Global events:
<div data-action="resize@window->gallery#layout">
<div data-action="keydown@document->modal#close">
Keyboard filters:
<input data-action="keydown.enter->search#submit">
<input data-action="keydown.esc->modal#close">
<input data-action="keydown.ctrl+s->form#save">
Action options:
| Option | Effect |
|---|---|
:stop |
Calls stopPropagation() |
:prevent |
Calls preventDefault() |
:self |
Only fires if target matches element |
:capture |
Use capture phase |
:once |
Remove after first invocation |
:passive |
Passive event listener |
<form data-action="submit->form#save:prevent">
<a data-action="click->link#track:stop">
Action parameters:
<button data-action="item#delete"
data-item-id-param="123"
data-item-type-param="article">
delete(event) {
const { id, type } = event.params
// id = 123 (Number), type = "article" (String)
}
Classes
Define CSS class names as controller properties:
static classes = ["active", "loading"]
<div data-controller="toggle"
data-toggle-active-class="bg-blue-500"
data-toggle-loading-class="opacity-50">
this.activeClass // "bg-blue-500"
this.hasActiveClass // true
this.loadingClasses // ["opacity-50"]
Import Maps (Rails 7+)
# config/importmap.rb
pin "application"
pin "@hotwired/turbo-rails", to: "turbo.min.js"
pin "@hotwired/stimulus", to: "stimulus.min.js"
pin_all_from "app/javascript/controllers", under: "controllers"
bin/importmap pin lodash
bin/importmap pin chartkick --from jsdelivr
Additional Resources
Reference Files
references/stimulus-patterns.md- Common Stimulus controller patternsreferences/turbo-streams-advanced.md- Complex broadcasting scenarios