User:Admin

• INTRO
• ROUTES
• CREATE LIVEVIEWS
• EDIT LIVEVIEWS
• SUBSCRIBE

    Tab 1: Lorem ipsum...

  scope "/", AppWeb do
    pipe_through :browser
    live "/send", SendLive, :home
    live "/receive", ReceiveLive, :home
  end

Create two working minimalistic LiveViews.

One is named SendView and the other is ReceiveView .

The SendView consist of a single form field to send data to RecieveView. ReceiveView contains code to renders SendView data to its page.

To understand web socket configuration we will:

1. Create a one way data connection between the two LiveViews and explain clearly the relationship between the code pieces with a focus on data flow.

2. Edit the code to create a two-way connection between both live views.

3. Combine both LiveViews into one live view to send and receive.

4. Write code to store real time chat content to a database.

This may seem like pointless overkill and maybe it is. However, this is what has worked for me.

PUB SUB

Before we begin, I will share three small pieces of code with you. These are the main characters, or main components for what we will build.

AppWeb.Endpoint.subscribe()

AppWeb.Endpoint.broadcast()

def handle_info(msg, socket) do
    {:noreply, assign(socket)}
end

def handle_event(msg, params, socket) do
    {:noreply, socket}
end

We will ultimately weave these little pieces of code into a LiveView and create a chat application.

Create Two Minimalistic Vanilla LiveViews

In router.ex create the following routes:

  scope "/", AppWeb do
    pipe_through :browser
    live "/send", SendLive, :home
    live "/receive", ReceiveLive, :home
  end

In app_web create a folder named live. In the live folder create a file named send_live.ex.

Copy this code into it:

defmodule AppWeb.SendLive do
  use AppWeb, :live_view

  def mount(_params, _session, socket) do
    {:ok, assign(socket, data: " ")}
  end

  def handle_event("send", params, socket) do
    {:noreply, socket}
  end

  def render(assigns) do
    ~H"""
    <div>
      <h1>connection Send</h1>

      <form phx-submit="send">
        <input type="text" name="text" />
        <button type="submit">Send</button>
      </form>
    </div>
    """
  end
end

defmodule AppWeb.SendLive do
  use AppWeb, :live_view

  def mount(_params, _session, socket) do
    if connected?(socket) do
    end

    {:ok, assign(socket, username: username, messages: [])}
  end

  # def handle_info(%{event: "message", payload: message}, socket) do
  #   {:noreply, assign(socket, messages: socket.assigns.messages ++ [message])}
  # end

  def handle_event("send", %{"text" => text}, socket) do
    AppWeb.Endpoint.broadcast("connection input-1", "SOUND", %{
      text: text,
      name: socket.assigns.username
    })

    {:noreply, socket}
  end

  defp username do
    "User #{:rand.uniform(100)}"
  end

  def render(assigns) do
    ~H"""
    <div>
      <h1>connection Send</h1>
      <div
        class="messages"
        style="border: 1px solid #eee; height: 400px; overflow: scroll; margin-bottom: 8px;"
      >
      </div>
      <form phx-submit="send">
        <input type="text" name="text" />
        <button type="submit">Send</button>
      </form>
    </div>
    """
  end
end

defmodule AppWeb.ReceiveLive do
  use AppWeb, :live_view

  def mount(_params, _session, socket) do
    {:ok, assign(socket, messages: " ")}
  end

  def handle_info(msg, socket) do
    {:noreply, assign(socket, data: "")}
  end

  def render(assigns) do
    ~H"""
    <div>
      <h1>ReceiveLive Connection</h1>

      <%= for m <- [1,2,3,4,5] do %>
        <%= m %>
      <% end %>
    </div>
    """
  end
end

defmodule AppWeb.RecieveLive do
  use AppWeb, :live_view

  def mount(_params, _session, socket) do
    if connected?(socket) do
      AppWeb.Endpoint.subscribe("connection input-1")
    end

    {:ok, assign(socket, username: username, messages: [])}
  end

  def handle_info(%{event: "SOUND", payload: message}, socket) do
    {:noreply, assign(socket, messages: socket.assigns.messages ++ [message])}
  end

  # def handle_event("send", %{"text" => text}, socket) do
  #   AppWeb.Endpoint.broadcast("connection input-1", "message", %{
  #     text: text,
  #     name: "X"
  #   })

  #   {:noreply, socket}
  # end

  defp username do
    "User #{:rand.uniform(100)}"
  end

  def render(assigns) do
    ~H"""
    <div>
      <h1>connection Recieve Live</h1>

      <div
        class="messages"
        style="border: 1px solid #eee; height: 400px; overflow: scroll; margin-bottom: 8px;"
      >
        <%= for m <- @messages do %>
          <p style="margin: 2px;"><b><%= m.name %></b>: <%= m.text %></p>
        <% end %>
      </div>
    </div>
    """
  end
end

Open the /send route and the /receive route each in their own tab. You will now write code so the form in send sends data to the page in receive.

• How to Create Database Seed Data.
• How to Use Generators in a Real World Project
• How to Work with Database Data via Basic Commands and Custom Change sets.
• How to Render Database Data to LiveView (via Context Commands).
• How to Create a Chat using PubSub.
• How to Create Event Handlers in LiveView
• How to Create a Dynamic Route from Scratch.
• How to Use Elixirs Template language
• How to Work with Modal
• How to Use CSS From Scratch (Without bundler)
• How to use JS hooks

_________________________________________________

https://elixirschool.com/blog/live-view-live-component

Note:

mix phx.gen.html Alerts Alert alerts title:string content:text enabled:boolean

defmodule AppWeb.PageLive do
   use AppWeb, :live_view  
   alias App.Alerts
   def mount(_params, _session, socket)  do
	 {:ok, assign(socket, alerts: Alerts.list_alerts())}  
   end

   def render(assigns) do
     ~H"""
        <%= for alert <- @alerts do %>
        	<%= if alert.enabled  do %>
              <div><%= alert.content%></div>
              <% end %>

        <% end %>

	 """ 
   end

end

#_____________________________

  def check_for_single_selection(data) do 

      list = App.Alerts.list_alerts()

      IO.inspect list

      result = Enum.filter(list, fn x -> x.enabled == true end)
      IO.inspect "WORK_____________________________"  
      IO.inspect result 
      IO.inspect "WORK_____________________________"

      data

  end

__________________________________________________

Complex pattern matching https://www.youtube.com/watch?v=gCVWrM5BNVE

Genservers (and related, agent,task etc)

__________________________________________________

ECTO

query = from "artists", select:[:name]

Verbose:

Ecto.Query.from("artists", select[:name])

Repo.all(query)

1. => [%{name: "Miles Davis"}, %{name: "Bill Evans"}]

Repo.to_sql(:all, query)