Add support for Sendgrid unique arguments (beam-community#609)

Closes beam-community#592

Adds support for Sendgrid unique arguments. It includes 
a `with_unique_args` helper function in the SendGridHelper.

lib/bamboo/adapters/send_grid_adapter.ex

@@ -130,6 +130,7 @@ defmodule Bamboo.SendGridAdapter do
  |> put_bypass_list_management(email)
  |> put_google_analytics(email)
  |> put_ip_pool_name(email)
+ |> put_unique_args(email)
  end
 
  defp put_from(body, %Email{from: from}) do
@@ -440,4 +441,12 @@ defmodule Bamboo.SendGridAdapter do
  do: Map.put(body, :ip_pool_name, ip_pool_name)
 
  defp put_ip_pool_name(body, _), do: body
+
+ defp put_unique_args(body, %Email{private: %{unique_args: unique_args}})
+ when is_map(unique_args) do
+ body
+ |> Map.put(:unique_args, unique_args)
+ end
+
+ defp put_unique_args(body, _), do: body
 end

lib/bamboo/adapters/send_grid_helper.ex

@@ -22,6 +22,7 @@ defmodule Bamboo.SendGridHelper do
  @allowed_google_analytics_utm_params ~w(utm_source utm_medium utm_campaign utm_term utm_content)a
  @send_at_field :sendgrid_send_at
  @ip_pool_name_field :ip_pool_name
+ @unique_args :unique_args
 
  @doc """
  Specify the template for SendGrid to use for the context of the substitution
@@ -294,4 +295,25 @@ defmodule Bamboo.SendGridHelper do
  email
  |> Email.put_private(@ip_pool_name_field, ip_pool_name)
  end
+
+ @doc """
+ A map of unique arguments for this email. This will override any existing unique arguments.
+
+ ## Example
+
+ email
+ |> with_unique_args(%{new_arg_1: "new arg 1", new_arg_2: "new arg 2"})
+ """
+ def with_unique_args(email, unique_args) when is_map(unique_args) do
+ unique_args =
+ Map.get(email.private, @unique_args, %{})
+ |> Map.merge(unique_args)
+
+ email
+ |> Email.put_private(@unique_args, unique_args)
+ end
+
+ def with_unique_args(_email, _unique_args) do
+ raise "expected a map of unique arguments"
+ end
 end

test/lib/bamboo/adapters/send_grid_adapter_test.exs

@@ -628,6 +628,25 @@ defmodule Bamboo.SendGridAdapterTest do
  assert msg =~ ~r/'email' field/
  end
 
+ test "deliver/2 correctly handles with_unique_args" do
+ email = new_email()
+
+ unique_args = %{
+ new_arg1: "new arg 1",
+ new_arg2: "new arg 2",
+ new_arg3: "new arg 3"
+ }
+
+ email
+ |> Bamboo.SendGridHelper.with_unique_args(unique_args)
+ |> SendGridAdapter.deliver(@config)
+
+ assert_receive {:fake_sendgrid, %{params: params}}
+ assert params["unique_args"]["new_arg1"] == "new arg 1"
+ assert params["unique_args"]["new_arg2"] == "new arg 2"
+ assert params["unique_args"]["new_arg3"] == "new arg 3"
+ end
+
  test "deliver/2 will set sandbox mode correctly" do
  email = new_email()
  email |> SendGridAdapter.deliver(@config_with_sandbox_enabled)

test/lib/bamboo/adapters/send_grid_helper_test.exs

@@ -207,4 +207,28 @@ defmodule Bamboo.SendGridHelperTest do
  email = email |> with_ip_pool_name(@ip_pool_name)
  assert email.private[:ip_pool_name] == @ip_pool_name
  end
+
+ test "with_unique_args/2 merges multiple maps", %{email: email} do
+ email =
+ email
+ |> with_unique_args(%{new_arg_1: "new arg 1", new_arg_2: "new arg 2"})
+ |> with_unique_args(%{new_arg_3: "new arg 3"})
+
+ assert map_size(email.private[:unique_args]) == 3
+ end
+
+ test "with_unique_args/2 overrides duplicate entries", %{email: email} do
+ email =
+ email
+ |> with_unique_args(%{new_arg_1: "new arg 1"})
+ |> with_unique_args(%{new_arg_1: "latest new arg 1", new_arg_2: "new arg 2"})
+
+ assert map_size(email.private[:unique_args]) == 2
+ end
+
+ test "with_unique_args/2 raises on non-map parameter", %{email: email} do
+ assert_raise RuntimeError, fn ->
+ email |> with_unique_args(["new arg"])
+ end
+ end
 end