Reorganize Payment Gateway Structure and Fix Payment Method Creation

README.md

@@ -53,7 +53,9 @@ config :ryal_core,
   user_module: App.User,
   user_table: :users,
   default_payment_gateway: :bogus,
-  fallback_payment_gateways: [:stripe, :braintree]
+  payment_gateways: %{
+    stripe: "sk_test_123"
+  }
 ```
 
 Now you'll want to copy over the migrations.

apps/ryal_core/lib/ryal.ex

@@ -3,15 +3,22 @@ defmodule Ryal do
   The core Ryal namespace. This guy is primarily used for configuration.
   """
 
-  @payment_gateway Application.get_env(:ryal_core, :payment_gateway)
-  @repo Application.get_env(:ryal_core, :repo)
-  @user_module Application.get_env(:ryal_core, :user_module)
-  @user_table Application.get_env(:ryal_core, :user_table)
-
   use Application
 
-  def payment_gateway, do: @payment_gateway
-  def payment_gateway_keys, do: Map.get(@payment_gateway, :keys) || %{}
+  import Application, only: [get_env: 2]
+
+  @default_payment_gateway get_env(:ryal_core, :default_payment_gateway)
+  @payment_gateways get_env(:ryal_core, :payment_gateways)
+
+  @repo get_env(:ryal_core, :repo)
+  @user_module get_env(:ryal_core, :user_module)
+  @user_table get_env(:ryal_core, :user_table)
+
+  def payment_gateways, do: @payment_gateways
+  def default_payment_gateway, do: @default_payment_gateway
+  def fallback_gateways do
+    Map.keys(payment_gateways() || %{}) -- [default_payment_gateway()]
+  end
 
   def repo, do: @repo
   def user_module, do: @user_module

apps/ryal_core/lib/ryal/web/commands/payment_gateway_command.ex

@@ -5,17 +5,16 @@ defmodule Ryal.PaymentGatewayCommand do
   """
 
   alias Ryal.PaymentGateway
-  alias Ryal.PaymentGateway.Customer
-
-  @default_gateway Map.get(Ryal.payment_gateway, :default)
-  @fallback_gateways Map.get(Ryal.payment_gateway, :fallbacks)
 
+  @doc "Shorthand for creating all the payment gateways relevant to a user."
+  @spec create(Ecto.Schema.t) ::
+     {:ok, Ecto.Schema.t} | {:error, Ecto.Changeset.t}
   def create(user) do
-    Enum.each @fallback_gateways || [], fn(gateway_type) ->
+    Enum.each Ryal.fallback_gateways() || [], fn(gateway_type) ->
       spawn_monitor fn -> create(gateway_type, user) end
     end
 
-    create @default_gateway, user
+    create Ryal.default_payment_gateway(), user
   end
 
   @doc """
@@ -27,7 +26,7 @@ defmodule Ryal.PaymentGatewayCommand do
   def create(type, user) do
     struct = %PaymentGateway{type: Atom.to_string(type), user_id: user.id}
 
-    with {:ok, external_id} <- Customer.create(type, user),
+    with {:ok, external_id} <- payment_gateway(type).create(:customer, user),
          changeset <-
            PaymentGateway.changeset(%{struct | external_id: external_id}),
       do: Ryal.repo.insert(changeset)
@@ -52,7 +51,17 @@ defmodule Ryal.PaymentGatewayCommand do
 
     Enum.map user.payment_gateways, fn(payment_gateway) ->
       type = String.to_atom payment_gateway.type
-      spawn_monitor Customer, action, [type, payment_gateway]
+      spawn_monitor payment_gateway(type), action, [:customer, payment_gateway]
     end
   end
+
+  defp payment_gateway(type) do
+    module_type = type
+      |> Atom.to_string
+      |> Macro.camelize
+
+    {module, []} = Code.eval_string("Ryal.PaymentGateway.#{module_type}")
+
+    module
+  end
 end

apps/ryal_core/lib/ryal/web/models/payment_gateways/bogus.ex

@@ -0,0 +1,25 @@
+defmodule Ryal.PaymentGateway.Bogus do
+  @moduledoc """
+  A very simple payment gateway module that provides the basic functions to fake
+  create, update, and delete methods with a payment gateway.
+  """
+
+  @doc "Simple bogus create function for an external_id."
+  @spec create(atom, Ecto.Schema.t) :: {:ok, String.t}
+  def create(_atom, _schema), do: {:ok, random_id()}
+
+  @doc "Simple bogus update function."
+  @spec update(atom, Ecto.Schema.t) :: {:ok, %{}}
+  def update(_atom, _schema), do: {:ok, %{}}
+
+  @doc "Simple bogus delete function."
+  @spec delete(atom, Ecto.Schema.t) :: {:ok, %{}}
+  def delete(_atom, _schema), do: {:ok, %{}}
+
+  defp random_id do
+    :rand.uniform * 10_000_000_000
+    |> round
+    |> to_string
+    |> String.ljust(10, ?0)
+  end
+end

apps/ryal_core/lib/ryal/web/models/payment_gateways/stripe.ex

@@ -0,0 +1,76 @@
+defmodule Ryal.PaymentGateway.Stripe do
+  @moduledoc "Relevant functions for working with the Stipe API."
+
+  alias Ryal.PaymentGatewayQuery
+
+  @stripe_api_key Map.get(Ryal.payment_gateways(), :stripe)
+  @stripe_base "https://#{@stripe_api_key}:@api.stripe.com"
+
+  @spec create(atom, Ecto.Schema.t, String.t) :: {:ok, String.t}
+  def create(type, schema, stripe_base \\ @stripe_base)
+
+  def create(:credit_card, payment_method, stripe_base) do
+    credit_card_data = payment_method.proxy.data
+    customer_id = payment_method.user_id
+      |> PaymentGatewayQuery.get_external_id("stripe")
+      |> Ryal.repo.one!
+
+    credit_card_path = "/v1/customers/#{customer_id}/sources"
+    create_object credit_card_data, :credit_card, credit_card_path, stripe_base
+  end
+
+  def create(:customer, user, stripe_base) do
+    create_object user, :customer, "/v1/customers", stripe_base
+  end
+
+  defp create_object(schema, type, path, stripe_base) do
+    response = HTTPotion.post(stripe_base <> path, [body: params(type, schema)])
+
+    with {:ok, body} <- Poison.decode(response.body),
+      do: {:ok, body["id"]}
+  end
+
+  @spec update(atom, Ecto.Schema.t, String.t) :: {:ok, %{}}
+  def update(type, schema, stripe_base \\ @stripe_base)
+
+  @doc "Updates information on Stripe when the user data changes."
+  def update(:customer, payment_gateway, stripe_base)  do
+    user = payment_gateway.user
+
+    response = stripe_base
+      <> "/v1/customers/#{payment_gateway.external_id}"
+      |> HTTPotion.post([body: params(:customer, user)])
+
+    Poison.decode(response.body)
+  end
+
+  @spec delete(atom, Ecto.Schema.t, String.t) :: {:ok, %{}}
+  def delete(atom, schema, stripe_base \\ @stripe_base)
+
+  @doc "Marks a customer account on Stripe as deleted."
+  def delete(:customer, payment_gateway, stripe_base) do
+    response = stripe_base
+      <> "/v1/customers/#{payment_gateway.external_id}"
+      |> HTTPotion.delete
+
+    Poison.decode(response.body)
+  end
+
+  defp params(:credit_card, credit_card) do
+    URI.encode_query %{
+      "source[object]" => "card",
+      "source[exp_month]" => credit_card.month,
+      "source[exp_year]" => credit_card.year,
+      "source[number]" => credit_card.number,
+      "source[cvc]" => credit_card.cvc,
+      "source[name]" => credit_card.name
+    }
+  end
+
+  defp params(:customer, user) do
+    URI.encode_query %{
+      email: user.email,
+      description: "Customer #{user.id} from Ryal."
+    }
+  end
+end

apps/ryal_core/lib/ryal/web/models/payment_method.ex

@@ -37,11 +37,13 @@ defmodule Ryal.PaymentMethod do
   schema "ryal_payment_methods" do
     field :type, :string
 
-    embeds_one :data, Ryal.PaymentMethod.Proxy
+    embeds_one :proxy, Ryal.PaymentMethod.Proxy
 
     has_many :payment_method_gateways, Ryal.PaymentMethodGateway
 
     belongs_to :user, Ryal.user_module()
+
+    timestamps()
   end
 
   @required_fields ~w(type user_id)a
@@ -58,15 +60,15 @@ defmodule Ryal.PaymentMethod do
     |> cast(set_module_type(params), @required_fields)
     |> validate_required(@required_fields)
     |> validate_inclusion(:type, @payment_method_types)
-    |> cast_embed(:data, required: true)
+    |> cast_embed(:proxy, required: true)
   end
 
   defp set_module_type(%{type: type} = params)
       when type in @payment_method_types do
     module_type = Macro.camelize(type)
     {module_name, []} = Code.eval_string("Ryal.PaymentMethod.#{module_type}")
-    data = Map.get(params, :data, %{})
-    Map.put(params, :data, struct(module_name, data))
+    proxy_data = Map.get(params, :proxy, %{})
+    Map.put(params, :proxy, struct(module_name, proxy_data))
   end
 
   defp set_module_type(params), do: params

apps/ryal_core/lib/ryal/web/models/payment_methods/proxy.ex

@@ -10,6 +10,7 @@ defmodule Ryal.PaymentMethod.Proxy do
   import Ecto.Changeset, only: [cast: 3]
 
   embedded_schema do
+    field :data, :map
   end
 
   @doc """
@@ -38,8 +39,15 @@ defmodule Ryal.PaymentMethod.Proxy do
     %module{} = struct
     params = Map.from_struct(struct)
 
-    module
-    |> struct(%{})
-    |> module.changeset(params)
+    proxy_changeset = module
+      |> struct(%{})
+      |> module.changeset(params)
+
+    %__MODULE__{}
+    |> cast(%{data: params}, [:data])
+    |> Map.merge(%{
+      errors: proxy_changeset.errors,
+      valid?: proxy_changeset.valid?
+    })
   end
 end

apps/ryal_core/lib/ryal/web/queries/payment_gateway_query.ex

@@ -0,0 +1,18 @@
+defmodule Ryal.PaymentGatewayQuery do
+  @moduledoc "Queries for the `Ryal.PaymentGateway`."
+
+  use Ryal.Web, :query
+
+  alias Ryal.PaymentGateway
+
+  @doc """
+  Have a user id and want to get its external_id to one of the payment
+  gateways? This query should help you out fine.
+  """
+  @spec get_external_id(integer, String.t) :: Ecto.Query.t
+  def get_external_id(user_id, gateway_type) do
+    from pg in PaymentGateway,
+      where: [user_id: ^user_id, type: ^gateway_type],
+      select: pg.external_id
+  end
+end

apps/ryal_core/priv/repo/migrations/20170225213108_create_ryal_payment_methods.exs

@@ -3,7 +3,8 @@ defmodule Ryal.Repo.Migrations.CreateRyalPaymentMethods do
 
   def change do
     create table(:ryal_payment_methods) do
-      add :data, :map, null: false
+      add :type, :string, null: false
+      add :proxy, :map, null: false
 
       add :user_id, references(Ryal.user_table()), null: false
 

apps/ryal_core/test/fixtures/stripe/credit_card.json

@@ -0,0 +1,24 @@
+{
+  "id": "card_1AA3En2BZSQJcNSQ77orWzVS",
+  "object": "card",
+  "address_city": null,
+  "address_country": null,
+  "address_line1": null,
+  "address_line1_check": null,
+  "address_line2": null,
+  "address_state": null,
+  "address_zip": null,
+  "address_zip_check": null,
+  "brand": "Visa",
+  "country": "US",
+  "customer": "cus_AUIXSS9KUHRv5H",
+  "cvc_check": null,
+  "dynamic_last4": null,
+  "exp_month": 8,
+  "exp_year": 2018,
+  "funding": "credit",
+  "last4": "4242",
+  "metadata": {},
+  "name": null,
+  "tokenization_method": null
+}