Skip to content
An integration with Arc and Ecto.
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.
config v0.1.0 release Jun 18, 2015
test Merge pull request #90 from joebew42/allow_urls-feature May 19, 2019
.gitignore v0.11.2 May 19, 2019 Update Nov 18, 2018


Arc.Ecto provides an integration with Arc and Ecto.


Add the latest stable release to your mix.exs file:

defp deps do
    {:arc_ecto, "~> 0.11.1"}

Then run mix deps.get in your shell to fetch the dependencies.


Add Arc.Ecto.Definition

Add a second using macro use Arc.Ecto.Definition to the top of your Arc definitions.

defmodule MyApp.Avatar do
  use Arc.Definition
  use Arc.Ecto.Definition

  # ...

This provides a set of functions to ease integration with Arc and Ecto. In particular:

  • Definition of a custom Ecto Type responsible for storing the images.
  • Url generation with a cache-busting timestamp query parameter

Add a string column to your schema

Arc attachments should be stored in a string column, with a name indicative of the attachment.

create table :users do
  add :avatar, :string

Add your attachment to your Ecto Schema

Add a using statement use Arc.Ecto.Schema to the top of your ecto schema, and specify the type of the column in your schema as MyApp.Avatar.Type.

Attachments can subsequently be passed to Arc's storage though a Changeset cast_attachments/3 function, following the syntax of cast/3

defmodule MyApp.User do
  use MyApp.Web, :model
  use Arc.Ecto.Schema

  schema "users" do
    field :name,   :string
    field :avatar, MyApp.Avatar.Type

  @doc """
  Creates a changeset based on the `data` and `params`.

  If no params are provided, an invalid changeset is returned
  with no validation performed.
  def changeset(user, params \\ :invalid) do
    |> cast(params, [:name])
    |> cast_attachments(params, [:avatar])
    |> validate_required([:name, :avatar])

Save your attachments as normal through your controller

  @doc """
  Given params of:

    "id" => 1,
    "user" => %{
      "avatar" => %Plug.Upload{
                    content_type: "image/png",
                    filename: "selfie.png",
                    path: "/var/folders/q0/dg42x390000gp/T//plug-1434/multipart-765369-5"}

  def update(conn, %{"id" => id, "user" => user_params}) do
    user = Repo.get(User, id)
    changeset = User.changeset(user, user_params)

    if changeset.valid? do

      |> put_flash(:info, "User updated successfully.")
      |> redirect(to: user_path(conn, :index))
      render conn, "edit.html", user: user, changeset: changeset

Retrieve the serialized url

Both public and signed urls will include the timestamp for cache busting, and are retrieved the exact same way as using Arc directly.

  user = Repo.get(User, 1)

  # To receive a single rendition:
  MyApp.Avatar.url({user.avatar, user}, :thumb)
    #=> ""

  # To receive all renditions:
  MyApp.Avatar.urls({user.avatar, user})
    #=> %{original: "https://.../original.png?v=1234", thumb: "https://.../thumb.png?v=1234"}

  # To receive a signed url:
  MyApp.Avatar.url({user.avatar, user}, signed: true)
  MyApp.Avatar.url({user.avatar, user}, :thumb, signed: true)


Copyright 2015 Sean Stavropoulos

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

You can’t perform that action at this time.