Casts an upload in the params under the given key, uploads it, and assigns it to the field.

Any options passed to this function will be passed through to Upload.cast.

You can also provide an option :with, which will allow you to use a custom uploader. You can use this mechanism to add validation to your file uploads. See the documentation about Upload.Uploader for more information.

Example

def changeset(user, params \ %{}) do
  user
  |> cast(params, [:name])
  |> Upload.Ecto.cast_upload(:logo)
end

def changeset(user, params \ %{}) do
  user
  |> cast(params, [:name])
  |> Upload.Ecto.cast_upload(:logo, prefix: ["logos"])
end

def changeset(user, params \ %{}) do
  user
  |> cast(params, [:name])
  |> Upload.Ecto.cast_upload(:logo, with: MyCustomUploader)
end

Casts a path in the params under a given key, uploads it, and assigns it to the field.

This function accepts the same options that Upload.Ecto.cast_upload/2 accepts.

Add the Upload’s key to the changeset for the given field.

If the file hasn’t been uploaded yet, it will be.