Defines a mailer.

A mailer is a wrapper around an adapter that makes it easy for you to swap the adapter without having to change your code.

It is also responsible for doing some sanity checks before handing down the email to the adapter.

When used, the mailer expects :otp_app as an option. The :otp_app should point to an OTP application that has the mailer configuration. For example, the mailer:

defmodule Sample.Mailer do
  use ExPostmark.Mailer, otp_app: :sample
end

Could be configured with:

config :sample, Sample.Mailer,
  adapter: ExPostmark.Adapters.Postmark,
  api_key: "abc123"

Examples

Once configured you can use your mailer like this:

# in an IEx console
iex> email = new |> from("tony.stark@example.com") |> to("steve.rogers@example.com")
%ExPostmark.Email{from: {"", "tony.stark@example.com"}, ...}
iex> Mailer.deliver(email)
:ok