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authorJavan Makhmali <javan@javan.us>2019-01-05 06:18:15 -0800
committerGitHub <noreply@github.com>2019-01-05 06:18:15 -0800
commit2832ca131dd43e15e410af75c1a32664b11595c0 (patch)
tree27f9c70ff3d0ac01a24c6d7d9d15f4fd8bfe32b0
parent86517942e469193e8624d5078d718785552c1270 (diff)
parent195da08ef7c187ac2ae743519973701dde4dc5a8 (diff)
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Merge pull request #34709 from gmcgibbon/action_cable_guides_es6
Use ES6 and Webpacker in ActionCable guide.
-rw-r--r--guides/source/action_cable_overview.md272
1 files changed, 160 insertions, 112 deletions
diff --git a/guides/source/action_cable_overview.md b/guides/source/action_cable_overview.md
index 2f602c3e0a..7809607574 100644
--- a/guides/source/action_cable_overview.md
+++ b/guides/source/action_cable_overview.md
@@ -147,16 +147,13 @@ established using the following JavaScript, which is generated by default by Rai
#### Connect Consumer
```js
-// app/assets/javascripts/cable.js
-//= require action_cable
-//= require_self
-//= require_tree ./channels
+// app/javascript/channels/consumer.js
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the `rails generate channel` command.
-(function() {
- this.App || (this.App = {});
+import ActionCable from "actioncable"
- App.cable = ActionCable.createConsumer();
-}).call(this);
+export default ActionCable.createConsumer()
```
This will ready a consumer that'll connect against `/cable` on your server by default.
@@ -167,12 +164,16 @@ you're interested in having.
A consumer becomes a subscriber by creating a subscription to a given channel:
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/chat.coffee
-App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" }
+```js
+// app/javascript/cable/subscriptions/chat_channel.js
+import consumer from "./consumer"
+
+consumer.subscriptions.create({ channel: "ChatChannel", room: "Best Room" })
+
+// app/javascript/cable/subscriptions/appearance_channel.js
+import consumer from "./consumer"
-# app/assets/javascripts/cable/subscriptions/appearance.coffee
-App.cable.subscriptions.create { channel: "AppearanceChannel" }
+consumer.subscriptions.create({ channel: "AppearanceChannel" })
```
While this creates the subscription, the functionality needed to respond to
@@ -181,9 +182,12 @@ received data will be described later on.
A consumer can act as a subscriber to a given channel any number of times. For
example, a consumer could subscribe to multiple chat rooms at the same time:
-```coffeescript
-App.cable.subscriptions.create { channel: "ChatChannel", room: "1st Room" }
-App.cable.subscriptions.create { channel: "ChatChannel", room: "2nd Room" }
+```js
+// app/javascript/cable/subscriptions/chat_channel.js
+import consumer from "./consumer"
+
+consumer.subscriptions.create({ channel: "ChatChannel", room: "1st Room" })
+consumer.subscriptions.create({ channel: "ChatChannel", room: "2nd Room" })
```
## Client-Server Interactions
@@ -256,24 +260,31 @@ When a consumer is subscribed to a channel, they act as a subscriber. This
connection is called a subscription. Incoming messages are then routed to
these channel subscriptions based on an identifier sent by the cable consumer.
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/chat.coffee
-# Assumes you've already requested the right to send web notifications
-App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
- received: (data) ->
- @appendLine(data)
-
- appendLine: (data) ->
- html = @createLine(data)
- $("[data-chat-room='Best Room']").append(html)
-
- createLine: (data) ->
- """
- <article class="chat-line">
- <span class="speaker">#{data["sent_by"]}</span>
- <span class="body">#{data["body"]}</span>
- </article>
- """
+```js
+// app/javascript/cable/subscriptions/chat_channel.js
+// Assumes you've already requested the right to send web notifications
+import consumer from "./consumer"
+
+consumer.subscriptions.create({ channel: "ChatChannel", room: "Best Room" }, {
+ received(data) {
+ this.appendLine(data)
+ },
+
+ appendLine(data) {
+ const html = this.createLine(data)
+ const element = document.querySelector("[data-chat-room='Best Room']")
+ element.insertAdjacentHTML("beforeend", html)
+ },
+
+ createLine(data) {
+ return `
+ <article class="chat-line">
+ <span class="speaker">${data["sent_by"]}</span>
+ <span class="body">${data["body"]}</span>
+ </article>
+ `
+ }
+})
```
### Passing Parameters to Channels
@@ -293,23 +304,30 @@ end
An object passed as the first argument to `subscriptions.create` becomes the
params hash in the cable channel. The keyword `channel` is required:
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/chat.coffee
-App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
- received: (data) ->
- @appendLine(data)
-
- appendLine: (data) ->
- html = @createLine(data)
- $("[data-chat-room='Best Room']").append(html)
-
- createLine: (data) ->
- """
- <article class="chat-line">
- <span class="speaker">#{data["sent_by"]}</span>
- <span class="body">#{data["body"]}</span>
- </article>
- """
+```js
+// app/javascript/cable/subscriptions/chat_channel.js
+import consumer from "./consumer"
+
+consumer.subscriptions.create({ channel: "ChatChannel", room: "Best Room" }, {
+ received(data) {
+ this.appendLine(data)
+ },
+
+ appendLine(data) {
+ const html = this.createLine(data)
+ const element = document.querySelector("[data-chat-room='Best Room']")
+ element.insertAdjacentHTML("beforeend", html)
+ },
+
+ createLine(data) {
+ return `
+ <article class="chat-line">
+ <span class="speaker">${data["sent_by"]}</span>
+ <span class="body">${data["body"]}</span>
+ </article>
+ `
+ }
+})
```
```ruby
@@ -340,13 +358,17 @@ class ChatChannel < ApplicationCable::Channel
end
```
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/chat.coffee
-App.chatChannel = App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
- received: (data) ->
- # data => { sent_by: "Paul", body: "This is a cool chat app." }
+```js
+// app/javascript/cable/subscriptions/chat_channel.js
+import consumer from "./consumer"
+
+const chatChannel = consumer.subscriptions.create({ channel: "ChatChannel", room: "Best Room" }, {
+ received(data) {
+ // data => { sent_by: "Paul", body: "This is a cool chat app." }
+ }
+}
-App.chatChannel.send({ sent_by: "Paul", body: "This is a cool chat app." })
+chatChannel.send({ sent_by: "Paul", body: "This is a cool chat app." })
```
The rebroadcast will be received by all connected clients, _including_ the
@@ -396,46 +418,69 @@ appear/disappear API could be backed by Redis, a database, or whatever else.
Create the client-side appearance channel subscription:
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/appearance.coffee
-App.cable.subscriptions.create "AppearanceChannel",
- # Called when the subscription is ready for use on the server.
- connected: ->
- @install()
- @appear()
-
- # Called when the WebSocket connection is closed.
- disconnected: ->
- @uninstall()
-
- # Called when the subscription is rejected by the server.
- rejected: ->
- @uninstall()
-
- appear: ->
- # Calls `AppearanceChannel#appear(data)` on the server.
- @perform("appear", appearing_on: $("main").data("appearing-on"))
-
- away: ->
- # Calls `AppearanceChannel#away` on the server.
- @perform("away")
-
-
- buttonSelector = "[data-behavior~=appear_away]"
-
- install: ->
- $(document).on "turbolinks:load.appearance", =>
- @appear()
-
- $(document).on "click.appearance", buttonSelector, =>
- @away()
- false
-
- $(buttonSelector).show()
-
- uninstall: ->
- $(document).off(".appearance")
- $(buttonSelector).hide()
+```js
+// app/javascript/cable/subscriptions/appearance_channel.js
+import consumer from "./consumer"
+
+consumer.subscriptions.create("AppearanceChannel", {
+ // Called once when the subscription is created.
+ initialized() {
+ this.update = this.update.bind(this)
+ },
+
+ // Called when the subscription is ready for use on the server.
+ connected() {
+ this.install()
+ this.update()
+ },
+
+ // Called when the WebSocket connection is closed.
+ disconnected() {
+ this.uninstall()
+ },
+
+ // Called when the subscription is rejected by the server.
+ rejected() {
+ this.uninstall()
+ },
+
+ update() {
+ this.documentIsActive ? this.appear() : this.away()
+ },
+
+ appear() {
+ // Calls `AppearanceChannel#appear(data)` on the server.
+ this.perform("appear", { appearing_on: this.appearingOn })
+ },
+
+ away() {
+ // Calls `AppearanceChannel#away` on the server.
+ this.perform("away")
+ },
+
+ install() {
+ window.addEventListener("focus", this.update)
+ window.addEventListener("blur", this.update)
+ document.addEventListener("turbolinks:load", this.update)
+ document.addEventListener("visibilitychange", this.update)
+ },
+
+ uninstall() {
+ window.removeEventListener("focus", this.update)
+ window.removeEventListener("blur", this.update)
+ document.removeEventListener("turbolinks:load", this.update)
+ document.removeEventListener("visibilitychange", this.update)
+ },
+
+ get documentIsActive() {
+ return document.visibilityState == "visible" && document.hasFocus()
+ },
+
+ get appearingOn() {
+ const element = document.querySelector("[data-appearing-on]")
+ return element ? element.getAttribute("data-appearing-on") : null
+ }
+})
```
##### Client-Server Interaction
@@ -445,16 +490,16 @@ ActionCable.createConsumer("ws://cable.example.com")`. (`cable.js`). The
**Server** identifies this connection by `current_user`.
2. **Client** subscribes to the appearance channel via
-`App.cable.subscriptions.create(channel: "AppearanceChannel")`. (`appearance.coffee`)
+`consumer.subscriptions.create({ channel: "AppearanceChannel" })`. (`appearance_channel.js`)
3. **Server** recognizes a new subscription has been initiated for the
appearance channel and runs its `subscribed` callback, calling the `appear`
method on `current_user`. (`appearance_channel.rb`)
4. **Client** recognizes that a subscription has been established and calls
-`connected` (`appearance.coffee`) which in turn calls `@install` and `@appear`.
-`@appear` calls `AppearanceChannel#appear(data)` on the server, and supplies a
-data hash of `{ appearing_on: $("main").data("appearing-on") }`. This is
+`connected` (`appearance_channel.js`) which in turn calls `install` and `appear`.
+`appear` calls `AppearanceChannel#appear(data)` on the server, and supplies a
+data hash of `{ appearing_on: this.appearingOn }`. This is
possible because the server-side channel instance automatically exposes all
public methods declared on the class (minus the callbacks), so that these can be
reached as remote procedure calls via a subscription's `perform` method.
@@ -488,13 +533,17 @@ end
Create the client-side web notifications channel subscription:
-```coffeescript
-# app/assets/javascripts/cable/subscriptions/web_notifications.coffee
-# Client-side which assumes you've already requested
-# the right to send web notifications.
-App.cable.subscriptions.create "WebNotificationsChannel",
- received: (data) ->
- new Notification data["title"], body: data["body"]
+```js
+// app/javascript/cable/subscriptions/web_notifications_channel.js
+// Client-side which assumes you've already requested
+// the right to send web notifications.
+import consumer from "./consumer"
+
+consumer.subscriptions.create("WebNotificationsChannel", {
+ received(data) {
+ new Notification(data["title"], body: data["body"])
+ }
+})
```
Broadcast content to a web notification channel instance from elsewhere in your
@@ -629,10 +678,9 @@ class Application < Rails::Application
end
```
-You can use `App.cable = ActionCable.createConsumer()` to connect to the cable
-server if `action_cable_meta_tag` is invoked in the layout. A custom path is
-specified as first argument to `createConsumer` (e.g. `App.cable =
-ActionCable.createConsumer("/websocket")`).
+You can use `ActionCable.createConsumer()` to connect to the cable
+server if `action_cable_meta_tag` is invoked in the layout. Otherwise, A path is
+specified as first argument to `createConsumer` (e.g. `ActionCable.createConsumer("/websocket")`).
For every instance of your server you create and for every worker your server
spawns, you will also have a new instance of Action Cable, but the use of Redis