Uploadex

Uploadex is an Elixir library for handling uploads using Ecto and Arc.

Documentation can be found at https://hexdocs.pm/uploadex.

Installation

The package can be installed by adding uploadex to your list of dependencies in mix.exs:

def deps do
  [
    {:uploadex, "~> 0.1.0"}
  ]
end

Usage

This library is built on top of Arc, so you can configure it normally. To use the default configuration, storing to the disk, no configuration is needed.

Then, define your uploader:

defmodule MyApp.MyUploader do
  use Uploadex.Definition,
    repo: MyApp.Repo

  ## Functions required for Uploadex.Definition

  def base_directory do
    Path.join(:code.priv_dir(:my_app), "static/")
  end

  def get_files(%MyApp.User{photo: photo}), do: photo

  # For this example, we assume company has_many :photos, and each photo has a file field.
  # For this to work properly, we will need cast_assoc :photos when inserting/updating a company.
  def get_files(%MyApp.Company{} = company) do
    company
    |> MyApp.Repo.preload(:photos)
    |> Map.get(:photos)
    |> Enum.map(& &1.file)
  end

  ## We can also define the functions for Arc.Definition here

  def storage_dir(_version, {_file, %User{id: user_id}}) do
    Path.join(base_directory(), "/uploads/users/\#{user_id}")
  end

  def storage_dir(_version, {_file, %Company{id: id}}) do
    Path.join(base_directory(), "/uploads/companies/\#{id}")
  end
end

In your schema, use the Ecto Type Uploadex.Upload:

schema "users" do
  field :name, :string
  field :photo, Uploadex.Upload
end

# No special cast is needed, and casting does not have any side effects.
def create_changeset(%User{} = user, attrs) do
  user
  |> cast(attrs, [:name, :photo])
end

Now, you can use the Uploadex functions to handle your records with their files:

defmodule MyApp.Accounts do
  alias MyApp.Accounts.User
  alias MyApp.MyUploader

  def create_user(attrs) do
    %User{}
    |> User.create_changeset(attrs)
    |> Uploadex.create_with_file(MyUploader)
  end

  def update_user(%User{} = user, attrs) do
    user
    |> User.update_changeset(attrs)
    |> Uploadex.update_with_file(user, MyUploader)
  end

  def delete_user(%User{} = user) do
    user
    |> Ecto.Changeset.change()
    |> Uploadex.delete_with_file(MyUploader)
  end
end

For more flexibility, you can use the Files module directly.

Motivation

Even though there already exists a library to integrate Arc with Ecto (https://github.com/stavro/arc_ecto), this library was created because:

• arc_ecto does not support upload of binary files
• Uploadex makes it easier to deal with records that contain files without having to manage those files manually on every operation
• Using uploadex, the changeset operations have no side-effects and special casting is needed