create-live-resource

Creating a Backpex LiveResource

You are an expert at creating LiveResources for Backpex. When the user wants to create a new admin resource, follow this process:

1. Identify the Ecto schema the resource will manage
2. Generate the LiveResource module with adapter_config, fields, and callbacks
3. Add the route to the router

LiveResource Module Structure

defmodule MyAppWeb.PostLive do
  use Backpex.LiveResource,
    adapter_config: [
      schema: MyApp.Post,
      repo: MyApp.Repo,
      update_changeset: &MyApp.Post.changeset/3,
      create_changeset: &MyApp.Post.changeset/3
    ]

  @impl Backpex.LiveResource
  def layout(_assigns), do: {MyAppWeb.Layouts, :admin}

  @impl Backpex.LiveResource
  def singular_name, do: "Post"

  @impl Backpex.LiveResource
  def plural_name, do: "Posts"

  @impl Backpex.LiveResource
  def fields do
    [
      title: %{
        module: Backpex.Fields.Text,
        label: "Title",
        searchable: true
      }
    ]
  end
end

use Backpex.LiveResource Options

adapter_config (Ecto)

The metadata keyword list contains :assigns and :target (the form field that triggered the change).

The item_query function must build on the incoming query argument (use from p in query, ...), not the schema directly.

Required Callbacks

Optional Callbacks

Router Setup

import Backpex.Router

scope "/admin", MyAppWeb do
  pipe_through :browser

  backpex_routes()

  live_session :admin, on_mount: Backpex.InitAssigns do
    live_resources "/posts", PostLive
    live_resources "/users", UserLive
    live_resources "/categories", CategoryLive, only: [:index, :show]
  end
end

backpex_routes() must appear once per scope. live_resources/3 generates routes for Index, Form (new/edit), and Show views.

Options for live_resources/3:

• only: [:index, :show, :new, :edit] to restrict routes
• except: [:new] to exclude specific routes

Complete Example

defmodule MyAppWeb.ProductLive do
  use Backpex.LiveResource,
    adapter_config: [
      schema: MyApp.Product,
      repo: MyApp.Repo,
      update_changeset: &MyApp.Product.changeset/3,
      create_changeset: &MyApp.Product.changeset/3,
      item_query: &__MODULE__.item_query/3
    ],
    per_page_default: 25,
    init_order: %{by: :inserted_at, direction: :desc}

  import Ecto.Query

  @impl Backpex.LiveResource
  def layout(_assigns), do: {MyAppWeb.Layouts, :admin}

  @impl Backpex.LiveResource
  def singular_name, do: "Product"

  @impl Backpex.LiveResource
  def plural_name, do: "Products"

  @impl Backpex.LiveResource
  def panels do
    [details: "Details", metadata: "Metadata"]
  end

  @impl Backpex.LiveResource
  def fields do
    [
      name: %{
        module: Backpex.Fields.Text,
        label: "Name",
        searchable: true,
        panel: :details
      },
      price: %{
        module: Backpex.Fields.Currency,
        label: "Price",
        panel: :details
      },
      category: %{
        module: Backpex.Fields.BelongsTo,
        label: "Category",
        display_field: :name,
        live_resource: MyAppWeb.CategoryLive,
        panel: :details
      },
      published: %{
        module: Backpex.Fields.Boolean,
        label: "Published",
        index_editable: true
      },
      inserted_at: %{
        module: Backpex.Fields.DateTime,
        label: "Created At",
        only: [:index, :show],
        panel: :metadata
      }
    ]
  end

  @impl Backpex.LiveResource
  def can?(_assigns, :delete, item), do: not item.published
  def can?(_assigns, _action, _item), do: true

  def item_query(query, _live_action, _assigns) do
    from p in query, where: is_nil(p.archived_at)
  end
end

Conventions

• File location: lib/my_app_web/live/<resource>_live.ex
• Module naming: MyAppWeb.<Resource>Live (e.g. MyAppWeb.ProductLive)
• Changeset functions should accept 3 arguments: item, attrs, metadata
• Use layout/1 callback instead of the layout: option (avoids compile-time dependencies)
• Always build on the incoming query in item_query/3