LiveAttribute (LiveAttribute v1.1.1) View Source

LiveAttribute makes binding updateable values easier. To use it add it to your LiveView using use LiveAttribute and then use the function assign_attribute(socket, subscribe_callback, property_callbacks) to register attributes.

The attributes will listen to all incoming events and update their assigns of your LiveView automatically, saving you the hassle of implementing independent handle_info() and update_...() calls.

Example using LiveAttribute

defmodule UserLive do
  use Phoenix.LiveView
  use LiveAttribute

  def mount(_params, _session, socket) do
    {:ok, assign_attribute(socket, &Accounts.subscribe/0, users: &Accounts.list_users/0)}
  end

  def handle_event("delete_user", %{"id" => user_id}, socket) do
    Accounts.get_user!(user_id)
    |> Accounts.delete_user()

    {:noreply, socket}
  end
end

Same Example without LiveAttribute

defmodule UserLive do
  use Phoenix.LiveView

  def mount(_params, _session, socket) do
    if connected?(socket), do: Accounts.subscribe()
    {:ok, update_users(socket)}
  end

  defp update_users(socket) do
    users = Accounts.list_users()
    assign(socket, users: users)
  end

  def handle_event("delete_user", %{"id" => user_id}, socket) do
    Accounts.get_user!(user_id)
    |> Accounts.delete_user()

    {:noreply, socket}
  end

  def handle_info({Accounts, [:user, _], _}, socket) do
    {:noreply, update_users(socket)}
  end
end

assign_attribute(socket, subscribe, filter \ :, refresher)

  • socket the LiveView socket where the assigns should be executed on
  • subscribe the subscribe callback to start the subscription e.g. &Users.subscribe/0
  • filter an optional filter if you don't want to update on each event. The filter can either be an expression using :_ as wildcard parameter such as {Accounts, [:user, :_], :_}. Alternatively filter can be a function with one parameter Note LiveAttribute is issuing each subscribe call in an isolated helper process, so you only need to add filters to reduce the scope of a single subscription.
  • refresher the function callback to load the new values after a subscription event has fired.

Link to this section Summary

Types

The refresher list or function.

Functions

Returns a specification to start this module under a supervisor.

Link to this section Types

Specs

refresher() ::
  [{atom(), (() -> any()) | (socket() -> any())}] | (socket() -> socket())

The refresher list or function.

Should preferably be a list of {key, callback} pairs to load the new attribute values. The callback thereby can have optionally one argument to read context from the socket.

Alternatively the refresher can be a single argument function instead of a list. In this case the function is applied to the socket and thus the user has to ensure that needed assign() calls are made manually.

Examples

iex> assign_attribute(socket, &User.subscribe(), users: &User.list_all/0)

iex> assign_attribute(socket, &User.subscribe(),

fn socket -> User.list_all() -- socket.assigns.blacklist end

) iex> assign_attribute(socket, &User.subscribe(), fn socket ->

assign(users: User.list_all() -- socket.assigns.blacklist)

end)

Specs

socket() :: map()

Link to this section Functions

Returns a specification to start this module under a supervisor.

See Supervisor.

Link to this function

update_attribute(socket, name)

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