rails 中 actioncable 的默认行为是什么？

Question

生成新频道时，注释掉stream_from方法调用。我知道，它适合识别流，比如 stream_from "comments_#{message.id}"。

但是如果这个频道没有这样的目标并且应该流式传输所有评论？未指定 stream_from 时此通道的默认行为（可能有价值）是什么？

Answer 1

假设您的频道名为 SomethingChannel

class SomethingChannel < ApplicationCable::Channel
  def subscribed
    # because you do not need stream_from, then remove the stream_from below
    # stream_from "something_channel"

    # and just immediately transmit the data. This should be a hash, and thus I use `as_json`; Change this accordingly as you see fit
    transmit(Comment.all.as_json)
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end
end

然后在客户端，您只需在需要时调用以下命令即可。

# ...coffee
App.cable.subscriptions.create 'SomethingChannel',
  connected: ->
    console.log('connected')

  # Called when the WebSocket connection is closed.
  disconnected: ->
    console.log('disconnected')

  # `transmit(Comment.all.as_json)` above will invoke this
  received: (data) ->
    console.log('received')
    console.log(data)

您应该会在 Google Chrome / Firefox 控制台中看到如下内容：

connected
received
▼ [{…}]
  ▶ 0: {id: 1, title: "Hello ", content: "World from Earth! :)", created_at: "2018-02-13T16:15:05.734Z", updated_at: "2018-02-13T16:15:05.734Z"}
  ▶ 1: {id: 2, title: "Lorem ", content: "Ipsum Dolor", created_at: "2018-02-13T16:15:05.734Z", updated_at: "2018-02-13T16:15:05.734Z"}
  length: 2
  ▶ __proto__: Array(0)

P.S。如果你不打算使用 stream_from 或 stream_for 那么也许你可能根本不需要 ActionCable，也许你最好从 [=29 检索所有评论=] 而不是（即 GET /comments）

rails 中 actioncable 的默认行为是什么？

What is default behavior for actioncable in rails?

ruby

ruby-on-rails

actioncable