RubyKaigi 2 0 2 6 LT Haruna Tsujita Rebuilding Turbo Streams with ruby.wasm and Ruby Sockets 

• Haruna Tsujita ‣ @haruna-tsujita ‣ @haruna_tsujita • Catal, Inc. • 🩷 Big fan of Hotwire. About me 

What's on the agenda today 今 日 話すこと • I’m going to walk you through how I re-implemented Turbo Streams in Ruby. Rubyを使ってTurbo Streamsの再実装をした話をします • I'd like to share the joy of coding my own ideas in Ruby! 自 分の好きなものをRubyで作る楽しさ を共有したいです！ 

browser server Add shopping 👆 e.g. append The browser sends a Turbo Streams-compatible request. ブラウザが Turbo Streams対応のリクエストを送る The server returns a tag. サーバーがタグを返す What's Turbo Streams? Turbo Streamsとは？ 

browser Turbo in the browser reads the target and action, then updates only the relevant section. ブラウザのTurboが対象と操作を読み取り、該当箇所を更新する shopping Add Add shopping 👆 Instead of the entire page, only this part gets updated. ページ全体でなく、この部分のみ更新 The browser sends a Turbo Streams-compatible request. ブラウザが Turbo Streams対応のリクエストを送る server The server returns a tag. サーバーがタグを返す e.g. append What's Turbo Streams? Turbo Streamsとは？ 

browser server Ruby Socket library ruby.wasm Turbo in the browser reads the target and action, then updates only the relevant section. ブラウザのTurboが対象と操作を読み取り、該当箇所を更新する The browser sends a Turbo Streams-compatible request. ブラウザが Turbo Streams対応のリクエストを送る The server returns a tag. サーバーがタグを返す What's Turbo Streams? Turbo Streamsとは？ 

Theme ? 

I asked an LLM. LLMに聞いてみました 

I want to reimplement Turbo Streams in Ruby. Could you suggest some names for the gem? Turbo StreamsをRubyで再実装したい。 gemの命名案をいくつか出して。 For Turbo + Ruby, "turby" or "tuby" seem like good options. Turbo + Ruby で ・ turby ・ tuby あたりが良さそうです Pondering … And then a note-taking app gets created. （そして作られるメモアプリ） 

A note-taking app at RubyKaigi? No way😇 さすがにRubyKaigiでメモアプリはない 

I came up with the theme myself. 人 間の頭でテーマを考えました 

Ruby × Turbo Streams × Hokkaido 

Ruby × Turbo Streams × Hokkaido ✨ ✨ Red and sparkly 赤 くてキラキラ 

Ruby × Turbo Streams × Hokkaido ✨ ✨ Red and sparkly ○ ○ ○ A flow of liquid or particles ○ ○ ○ 粒々 赤 くてキラキラ 

Ruby × Turbo Streams × Hokkaido ✨ ✨ Red and sparkly A flow of liquid or particles 🐟🦑🦀 ・ ・ ？？ ○ ○ ○ ○ ○ ○ 赤 くてキラキラ 粒々 

ikura salmon roe 

ikura • I created a gem called ikura. いくらを題材にした ikura というgemを作りました • I reimplemented Turbo Streams' append in Ruby. Turbo StreamsのappendアクションをRubyで再実装しました • It's designed so that you can add ikura grains on top of gunkan-maki. 軍艦巻きの上にいくらの粒を追加できる仕様にしました append gunkan-maki 

Tasks browser server GET request to / POST request to /ikura Respond with static HTML Add ikura with Turbo Streams Introduce ruby.wasm — a challenge to see how far I can go with pure Ruby. ruby.wasmを導 入 どこまでPure Rubyで書けるか挑戦 Introduce the Socket library — built from scratch without Rack or similar frameworks. RubyのSocketライブラリを導 入 Rackなどは使わず全て 自 前実装 

Versions Used • Ruby 4 . 0 . 2 • @ruby/wasm-wasi 2 . 8 . 1 （Ruby 4 . 0 ） 

require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end server Introduce the Socket library and start listening for new connections on the speci fi ed port. Socketライブラリを導 入 し、指定したPortに対して新しい接続待ちを始める 

require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end server browser (client) Wait for a connection from the client, and return a client object when one is established. クライアントからの接続を待ち、接続があればclientオブジェクトを返す 

server require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end browser (client) Parse the request from the client to retrieve the HTTP method, path, and headers. クライアントからのリクエストを解析して、HTTPメソッドやパス、ヘッダーを取得 req = { method: "GET", path: "/", headers: { … } } "GET / HTTP/ 1 . 1 \r\nHost: localhost: 8 0 8 0 \r\n Connection: keep-alive\r\n … " 

server require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end browser (client) html def handle(client, req) case [req[:method], req[:path]] in ["GET", "/"] respond(client, type: "text/html; charset=utf-8", body: html_page) … def respond(client, status: "200 OK", type:, body:) client.print "HTTP/1.1 #{status}\r\n" client.print "Content-Type: #{type}\r\n" client.print "Content-Length: #{body.bytesize}\r\n" client.print "\r\n" client.print body end Generate an appropriate response based on the request and send it back to the client. リクエストの内容に応じて適切なレスポンスを 生 成し、クライアントに返す ここでは/ へのGETリクエストに対応 

server require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end browser (client) html 🍣 Ikura … 

Tasks browser (client) server GET request to / POST request to /ikura Respond with static HTML Add ikura with Turbo Streams 

How do you add ikura? いくらをどう追加する？ • This is the part I thought about the most. 今回 一 番考えたのはここ • My initial idea was to place fi xed points in several locations and add ikura when clicked. （当初）クリック可能な点を複数箇所に置いて、それをクリックするといくらを追加できる仕様 ‣ 🤔 Fixed points make the ikura line up. 決めうちで クリックできる点 を置くといくらが整列してしまう ‣ 🤔 It looked unnatural, so I scrapped it. 不 自 然なので却下 ？ 

0 • Place clickable fi xed points, and when one is clicked, use `Kernel.#rand` to determine the x and y positions. クリック可能な点を複数配置し、それぞれを座標の交点として`Kernel.#rand`でx軸とy軸の位置を決定 ‣ Then recalculate the absolute values so they can be handled by CSS. さらにCSSで top, left の絶対値として扱えるよう位置の再計算を 行 う Each click on a fixed point places the ikura randomly. 配置した各交点をクリックすると 毎回ランダムにいくらを散らすことができる y x How do you add ikura? いくらをどう追加する？ 

bodyとしてブラウザに返すHTML GETで返すbodyにikura_pointsを配置 TEMPLATE_PATH = File.join(__dir__, "templates", "ikura.html.erb") IKURA_POINTS = [ [50, 50], [35, 50]… ].freeze def html_page ikura_points_html = IKURA_POINTS.each_with_index.map { |(left, top), i| "

🍣 Ikura import { DefaultRubyVM } from "https://cdn.jsdelivr.net/npm/@ruby/[email protected]/dist/browser/+esm"; const res = await fetch( "https://cdn.jsdelivr.net/npm/@ruby/[email protected]/dist/ ruby+stdlib.wasm"); const { rubyVm } = await DefaultRubyVM(await WebAssembly.compileStreaming(res)); browser (client) Browser Ruby Introduce ruby.wasm — a Ruby VM starts up inside the browser. ruby.wasmを導 入 ブラウザの中にRuby VM が 立 ち上がります server Local Ruby 

import { DefaultRubyVM } from "https://cdn.jsdelivr.net/npm/ @ruby/[email protected]/dist/browser/+esm"; const rubyWasmResponse = await fetch("https://cdn.jsdelivr.net/ npm/@ruby/[email protected]/dist/ruby+stdlib.wasm"); const { rubyVm } = await DefaultRubyVM(await WebAssembly.compileStreaming(rubyWasmResponse)); rubyVm.eval(` require "js" … ); browser (client) By launching Ruby VM inside a script tag, you can write Ruby code directly in the browser. This time, though, I couldn't quite make it work, so I ended up doing something completely backwards: requiring JavaScript from within it. scriptタグの中でRuby VMを 立 ち上げると、ブラウザの中にRubyのコードが書けるようになりますが、 今回は私の 力 不 足 で、scriptタグ内のRubyVMでJSをrequireするという本末転倒なことをしています Browser Ruby 

// ruby.wasmىಈ rubyVm.eval(` require "js" doc = JS.global[:document] nodes = doc.call(:querySelectorAll, ".ikura_point") nodes[:length].to_i.times do |i| node = nodes.call(:item, i) node[:style][:opacity] = "1" node.call(:addEventListener, "click", ->(event) { opts = JS.eval("return { method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, body: 'ikura_point=#{i}' }")`); browser (client) ・ ・ ・ ・ ・ server Prepare all elements with the .ikura_point class in HTML so that clicking any of them triggers a POST request. 先ほど追加した`.ikura_point`クラスを持つ 全ての要素に対して クリックしたらPOSTできるように下準備 

const { rubyVm } = await DefaultRubyVM(await WebAssembly.compileStreaming(res)); rubyVm.eval(` require "js" doc = JS.global[:document] nodes = doc.call(:querySelectorAll, ".ikura_point") nodes[:length].to_i.times do |i| node.call(:addEventListener, "click", ->(event) { … JS.global.fetch("/ikura", opts).call(:then, ->(response) { response.text().call(:then, ->(text) { doc = JS.global[:document] div = doc.call(:createElement, "div") div[:innerHTML] = text.to_s div.call(:querySelectorAll, "turbo-stream")[:length].to_i.times do |j| el = div.call(:querySelectorAll, "turbo-stream").call(:item, j) action = el.call(:getAttribute, "action").to_s target = el.call(:getAttribute, "target").to_s content = el.call(:querySelector, "template")[:innerHTML].to_s rescue "" target_node = doc.call(:getElementById, target) case action when "append" then target_node.call(:insertAdjacentHTML, "beforeend", content) end end Parse the Turbo Stream response received from the server and append the ikura HTML to the gunkan-maki. サーバーから受け取ったTurbo Streamsレスポンスを解析し、 いくらのHTMLを軍艦巻きの上にappendできるよう処理を追加 

require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end browser (client) "POST /ikura HTTP/ 1 . 1 \r\nHost: localhost: 8 0 8 0 \r\n … Content-Length: 1 4 \r\n\r\nikura_point= 1 5 " server To support POST requests, request parsing must also retain the body from the client. POSTリクエストに対応するため、 クライアントからのリクエスト解析時にbodyも保持するよう変更 req = { method: "POST", path: "/ikura", headers: { … }, body: ikura_point= 1 5 } 

require "socket" server = TCPServer.new(@port) # @port = 8080 loop do client = server.accept req = parse_request(client) next unless req handle(client, req) client.close rescue => e ... end end def handle(client, req) case [req[:method], req[:path]] in ["GET", "/"] … in ["POST", "/ikura"] idx = parse_form(req[:body])["ikura_point"]&.to_i x, y = IKURA_POINTS[idx] id = @ikura_count @ikura_count += 1 jx = (x + rand(-10..10)) jy = (y + rand(-10..10)) respond(client, type: "text/vnd.turbo-stream.html; charset=utf-8", body: %(

" For POST requests, create a Turbo Stream response and send it back to the browser. POSTリクエストに対して、 Turbo Streams形式のレスポンス を作成し、ブラウザに返す Preparation for scattering ikura randomly. いくらをランダムに散らす下準備 def respond(client, status: "200 OK", type:, body:) client.print "HTTP/1.1 #{status}\r\n" client.print "Content-Type: #{type}\r\n" client.print "Content-Length: #{body.bytesize}\r\n" … client.print "\r\n" client.print body end 

It's done! 

Demo