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HTML-over- WebSockets Vladimir Dementyev Evil Martians

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palkan_tula palkan github.com/palkan 2

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palkan_tula palkan Web applications 3

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palkan_tula palkan Web applications 4 Data Representation

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palkan_tula palkan Breakfast 🥐 5 Data Representation ?

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palkan_tula palkan Breakfast 🥬 6 Data Representation ?

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Canteen-style Ready-made Predeﬁned set of dishes Wait in line Cheap & simple

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Classic Rails Ready-made (HotW) Predeﬁned set of responses Wait in line (queueing) Cheap & simple

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DIY Raw food to cook Special equipment is required Expensive though tasty

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SPA Raw data to render Frontenders are required Expensive though "cool" 😎

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A la carte Waiters serve clients concurrently Order once, get fully-cooked food in batches Reﬁlls without requests The chef is a boss

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HTML-over-WS Server serves clients concurrently Subscribe once, get HTML asynchronously Live updates w/o requests The server is a boss

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palkan_tula palkan 13 Why does everyone try to build yet another Korean BBQ? Is HTML-over-WebSockets possible in 2021? The question

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YES

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palkan_tula palkan Frontendless Rails RailsConf 2021 15

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palkan_tula palkan Frontendless Rails (live) 16

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palkan_tula palkan HTML-over- WebSockets: The overview 17

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palkan_tula palkan Phoenix LiveView 18

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palkan_tula palkan Phoenix LiveView HTML elements «connects» to an Erlang process via WebSocket Process reacts on user interaction and internal server events, updates the state, re-renders the affected template parts and sends to the client Client uses morphdom to perform a fast DOM patching 19

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palkan_tula palkan morphdom 20

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palkan_tula palkan LiveView 21 https://my-live.app

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palkan_tula palkan LiveView 21 https://my-live.app DOM element

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palkan_tula palkan LiveView 21 https://my-live.app Erlang process DOM element

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palkan_tula palkan LiveView 21 https://my-live.app Browser events Erlang process DOM element

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palkan_tula palkan LiveView 21 https://my-live.app Browser events Partial HTML updates Erlang process DOM element

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palkan_tula palkan LiveView 21 https://my-live.app Browser events Partial HTML updates Internal events Erlang process DOM element

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palkan_tula palkan LiveView 21 https://my-live.app Browser events Partial HTML updates Internal events Erlang process DOM element

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palkan_tula palkan Partial HTML updates 22

" id="<%= dom_id(item) %>"> >

<%= item.desc %>

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palkan_tula palkan Partial HTML updates 23

" id="<%= dom_id(item) %>"> >

<%= item.desc %>

Static vs. Dynamic

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palkan_tula palkan Partial HTML updates 23

" id="<%= dom_id(item) %>"> >

<%= item.desc %>

Static vs. Dynamic 0 1 2 3

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palkan_tula palkan Partial HTML updates 23

" id="<%= dom_id(item) %>"> >

<%= item.desc %>

Static vs. Dynamic 0 1 2 3 { "0": "checked", "2": "checked" }

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palkan_tula palkan Phoenix LiveView Component-driven architecture Erlang ecosystem (processes and message passing) Dedicated templating mechanism 24

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palkan_tula palkan Back to Ruby 25

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palkan_tula palkan “A new way to craft modern, reactive web interfaces with Ruby on Rails.” 26

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palkan_tula palkan 27 Stimulus Reﬂex creator

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palkan_tula palkan 27 Stimulus Reﬂex creator CableReady 🤔

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palkan_tula palkan CableReady A library to broadcast DOM modiﬁcation commands from server to browsers Uses Action Cable as a transport Uses morphdom to update HTML 28

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palkan_tula palkan Example 29

... <%= button_to item_path(item), method: :delete, remote: true do %> ... <% end %>

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palkan_tula palkan Example 30 # items_controller.rb def destroy item.destroy! stream = ListChannel.broadcasting_for(item.list) cable_ready[stream].remove(selector: dom_id(item)) head :no_content end

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palkan_tula palkan # items_controller.rb def destroy item.destroy! stream = ListChannel.broadcasting_for(item.list) cable_ready[stream].remove(selector: dom_id(item)) head :no_content end Example 31 $(" ##{dom_id(item)}").remove()

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palkan_tula palkan CableReady 32 cableready.stimulusreﬂex.com

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palkan_tula palkan CableReady v5.0 Custom operations stream_from helper (like in Hotwire, see further) 33

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palkan_tula palkan StimulusReﬂex Reﬂexes react on user actions and render HTML responses CableReady is use to send HTML to clients and to update DOM 34

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No content

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palkan_tula palkan StimulusReﬂex 36 https://my-reﬂex.app

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palkan_tula palkan StimulusReﬂex 36 https://my-reﬂex.app DOM element

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palkan_tula palkan StimulusReflex 36 https://my-reflex.app Browser events ➝ reflex class & action Reflex class DOM element

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palkan_tula palkan StimulusReflex 36 https://my-reflex.app Browser events ➝ reflex class & action CableReady operation Reflex class DOM element Document

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palkan_tula palkan StimulusReflex 36 https://my-reflex.app Browser events ➝ reflex class & action CableReady operation Action Cable broadcast from anywhere Reflex class DOM element Document

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palkan_tula palkan StimulusReflex 36 https://my-reflex.app Browser events ➝ reflex class & action CableReady operation Action Cable broadcast from anywhere Reflex class DOM element Document

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palkan_tula palkan Example 37

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palkan_tula palkan Example 37

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palkan_tula palkan Example 38

data-reflex="change ->List#toggle_item_completion" data-item-id="<%= item.id %> > ...

<%= item.desc %>

...

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palkan_tula palkan Example 39 class ListReflex < ApplicationReflex def toggle_item_completion item = find_item item.toggle!(:completed) html = render_partial("items/item", {item}) selector = dom_id(item) cable_ready[ ListChannel.broadcasting_for(item.list) ].outer_html(selector:, html:) cable_ready.broadcast morph_flash :notice, "Item has been updated" end private def find_item Item.find element.dataset["item-id"] end end

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palkan_tula palkan Example 40 class ListReflex < ApplicationReflex def toggle_item_completion item = find_item item.toggle!(:completed) html = render_partial("items/item", {item}) selector = dom_id(item) cable_ready[ ListChannel.broadcasting_for(item.list) ].outer_html(selector:, html:) cable_ready.broadcast morph_flash :notice, "Item has been updated" end private def find_item Item.find element.dataset["item-id"] end end Broadcast DOM updates to all connected clients Show ﬂash-notiﬁcation to the current user Object representing the current element data attributes

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palkan_tula palkan Example 41 class ApplicationReflex < StimulusReflex ::Reflex private def morph_flash(type, message) morph "#flash", render_partial( "shared/alerts", {flash: {type => message}} ) end end

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palkan_tula palkan StimulusReflex Introduces a new abstraction layer (reflexes) Unscoped DOM updates (you can even update the whole page) DOM manipulations could be customized to infinity 42

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palkan_tula palkan StimulusReﬂex Stable & Mature (v3.4) Comprehensive documentation Active Discord community (>1k members) Works with AnyCable out-of-the-box 😉 43

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palkan_tula palkan StimulusReﬂex v4.0 Transport-agnostic (cables, SSE, message_bus, AJAX) Reliable data ﬂow 44

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palkan_tula palkan NEW MAGIC hotwire.dev 45

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palkan_tula palkan NEW MAGIC hotwire.dev 45

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palkan_tula palkan evilmartians.com/blog evilmartians.com/chronicles/hotwire-reactive-rails-with-no-javascript 46

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palkan_tula palkan Hotwire Demystiﬁed @jamie_gaskings at RailsConf 2021 47

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palkan_tula palkan Turbo Drive Poor man's SPA Intercepts navigation / forms submission, performs AJAX requests, replaces HTML body contents Keeps track of visited pages (cache) to provide smooth experience 48 ex-Turbolinks

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palkan_tula palkan Turbo Frames Turbolinks for page fragments (frames) Lazy loading of page parts (plays well with HTTP cache) 49

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palkan_tula palkan Example 50 # app/controllers/items_controller.rb class ItemsController < ApplicationController def update item.update!(item_params) render partial: "item", locals: {item} end def destroy item.destroy! render partial: "item", locals: {item} end end

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palkan_tula palkan Example 51 <% unless item.destroyed? %>

"> <%= form_for item do |f| %> <%= f.check_box :completed, class: item.completed? ? "hidden checked" : "hidden", onchange: "this.form.requestSubmit();" %> <% end %>

<%= item.desc %>

<%= button_to item_path(item), method: :delete do %> ... <% end %>

<% end %>

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palkan_tula palkan Turbo Streams Minimalistic CableReady (only 5 actions) Transport-agnostic Zero JavaScript (uses custom HTML elements to trigger updates) 52

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palkan_tula palkan Turbo Streams 53 https://my-hot.app

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palkan_tula palkan Turbo Streams 53 https://my-hot.app

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palkan_tula palkan Turbo Streams 53 https://my-hot.app Action Cable subscribe

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palkan_tula palkan Turbo Streams 53 https://my-hot.app GET/POST/... Rails controller Action Cable subscribe

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palkan_tula palkan Turbo Streams 53 https://my-hot.app GET/POST/... HTML Rails controller Action Cable subscribe

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palkan_tula palkan Turbo Streams 53 https://my-hot.app GET/POST/... HTML Action Cable broadcast from anywhere Rails controller Action Cable subscribe

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palkan_tula palkan DOM update Turbo Streams 53 https://my-hot.app GET/POST/... HTML Action Cable broadcast from anywhere Rails controller Action Cable subscribe

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palkan_tula palkan Turbo Streams 54

<%= turbo_stream_from workspace %>

<%= workspace.name %>

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palkan_tula palkan Turbo Streams 55 # app/controllers/chat/messages_controller.rb class MessagesController < ApplicationController def create Turbo ::StreamsChannel.broadcast_append_to( workspace, target: ActionView ::RecordIdentifier.dom_id(workspace, :chat_messages), partial: "chats/message", locals: {message: params[:message], name: current_user.name} ) head :ok end end

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palkan_tula palkan More HTML-over-WS Motion Live 56

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palkan_tula palkan Motion 57 github.com/unabridged/motion

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palkan_tula palkan Live 58 github.com/socketry/live

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palkan_tula palkan Live 59 class ClickCounter < Live ::View def initialize(id, **data) super @data[:count] ||= 0 end def handle(event, details) @data[:count] = Integer(@data[:count]) + 1 replace! end def render(builder) builder.tag :button, onclick: forward do builder.text("Add an image. ( #{@data[:count]} images so far).") end builder.tag :div do Integer(@data[:count]).times do builder.tag :img, src: "https: //picsum.photos/200/300" end end end end

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palkan_tula palkan Live 60 class ClickCounter < Live ::View def initialize(id, **data) super @data[:count] ||= 0 end def handle(event, details) @data[:count] = Integer(@data[:count]) + 1 replace! end def render(builder) builder.tag :button, onclick: forward do builder.text("Add an image. ( #{@data[:count]} images so far).") end builder.tag :div do Integer(@data[:count]).times do builder.tag :img, src: "https: //picsum.photos/200/300" end end end end

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palkan_tula palkan Motion / Live Conceptually closer to LiveView (stateful components) Does keeping view components state scale in Ruby? 🤔 61

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palkan_tula palkan HTML-over-WebSockets There are plenty of implementations already StimulusReﬂex and CableReady are rock solid! Hotwire is gaining popularity (and stability) Motion and Live are promising 62

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palkan_tula palkan HTML-over-WebSockets Gives full-stack development a second chance Worth considering if: You don't want to hire the whole new team Your app is based on user-server interactions You want to vitalize a classic Rails app 63

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THANKS! @palkan @palkan_tula evilmartians.com @evilmartians https://discord.gg/stimulus-reﬂex