From 0dbcd86c881442c916a1c8c5caaef2e89f9baa95 Mon Sep 17 00:00:00 2001
From: reichert621 <reichertjalex@gmail.com>
Date: Mon, 16 Nov 2020 23:09:06 -0500
Subject: [PATCH] Start playing around with setting up a public v1 API

---
 lib/chat_api/users.ex                    |  6 ++
 lib/chat_api_web/api_auth_plug.ex        |  1 +
 lib/chat_api_web/public_api_auth_plug.ex | 85 ++++++++++++++++++++++++
 lib/chat_api_web/router.ex               | 12 ++++
 4 files changed, 104 insertions(+)
 create mode 100644 lib/chat_api_web/public_api_auth_plug.ex

diff --git a/lib/chat_api/users.ex b/lib/chat_api/users.ex
index bc7805204..d9faaa44d 100644
--- a/lib/chat_api/users.ex
+++ b/lib/chat_api/users.ex
@@ -40,6 +40,12 @@ defmodule ChatApi.Users do
     User |> where(password_reset_token: ^token) |> Repo.one()
   end
 
+  @spec find_by_api_key(binary()) :: User.t() | nil
+  def find_by_api_key(_api_key) do
+    # TODO: implement me!
+    nil
+  end
+
   @spec send_password_reset_email(User.t()) ::
           ChatApi.Emails.deliver_result() | {:error, Ecto.Changeset.t()}
   def send_password_reset_email(user) do
diff --git a/lib/chat_api_web/api_auth_plug.ex b/lib/chat_api_web/api_auth_plug.ex
index a3902ab21..ec8ab5189 100644
--- a/lib/chat_api_web/api_auth_plug.ex
+++ b/lib/chat_api_web/api_auth_plug.ex
@@ -93,6 +93,7 @@ defmodule ChatApiWeb.APIAuthPlug do
   defp signing_salt(), do: Atom.to_string(__MODULE__)
 
   defp fetch_auth_token(conn, config) do
+    # TODO: if token isn't verified, check personal API keys?
     with [token | _rest] <- Conn.get_req_header(conn, "authorization"),
          {:ok, token} <- Plug.verify_token(conn, signing_salt(), token, config) do
       token
diff --git a/lib/chat_api_web/public_api_auth_plug.ex b/lib/chat_api_web/public_api_auth_plug.ex
new file mode 100644
index 000000000..5f203a49f
--- /dev/null
+++ b/lib/chat_api_web/public_api_auth_plug.ex
@@ -0,0 +1,85 @@
+defmodule ChatApiWeb.PublicAPIAuthPlug do
+  @moduledoc false
+  use Pow.Plug.Base
+
+  alias Plug.Conn
+  alias Pow.{Config, Store.CredentialsCache}
+
+  @impl true
+  @spec fetch(Conn.t(), Config.t()) :: {Conn.t(), map() | nil}
+  def fetch(conn, config) do
+    conn
+    |> fetch_auth_token(config)
+    |> fetch_user(conn, config)
+  end
+
+  defp fetch_user(nil, conn, _config), do: {conn, nil}
+
+  defp fetch_user(token, conn, config) do
+    case fetch_from_store(token, config) do
+      nil -> fetch_and_cache_user(token, conn, config)
+      user -> {conn, user}
+    end
+  end
+
+  defp fetch_and_cache_user(token, conn, config) do
+    case ChatApi.Users.find_by_api_key(token) do
+      nil ->
+        {conn, nil}
+
+      user ->
+        config
+        |> store_config()
+        |> CredentialsCache.put(token, {user, []})
+
+        {conn, user}
+    end
+  end
+
+  defp fetch_from_store(token, config) do
+    config
+    |> store_config()
+    |> CredentialsCache.get(token)
+    |> case do
+      :not_found -> nil
+      {user, _metadata} -> user
+    end
+  end
+
+  @impl true
+  @spec create(Conn.t(), map(), Config.t()) :: {Conn.t(), map()}
+  def create(conn, user, _config) do
+    {conn, user}
+  end
+
+  @impl true
+  @spec delete(Conn.t(), Config.t()) :: Conn.t()
+  def delete(conn, config) do
+    case fetch_auth_token(conn, config) do
+      nil ->
+        :ok
+
+      token ->
+        config
+        |> store_config()
+        |> CredentialsCache.delete(token)
+    end
+
+    conn
+  end
+
+  defp fetch_auth_token(conn, _config) do
+    with [token | _rest] <- Conn.get_req_header(conn, "authorization"),
+         "bearer " <> token <- String.downcase(token) do
+      token
+    else
+      _any -> nil
+    end
+  end
+
+  defp store_config(config) do
+    backend = Config.get(config, :cache_store_backend, Pow.Store.Backend.EtsCache)
+
+    [backend: backend]
+  end
+end
diff --git a/lib/chat_api_web/router.ex b/lib/chat_api_web/router.ex
index 04aabc9e6..53c42d52f 100644
--- a/lib/chat_api_web/router.ex
+++ b/lib/chat_api_web/router.ex
@@ -20,6 +20,12 @@ defmodule ChatApiWeb.Router do
     plug(ChatApiWeb.EnsureUserEnabledPlug)
   end
 
+  pipeline :public_api do
+    plug(ChatApiWeb.IPAddressPlug)
+    plug(:accepts, ["json"])
+    plug(ChatApiWeb.PublicAPIAuthPlug, otp_app: :chat_api)
+  end
+
   # Swagger
   scope "/api/swagger" do
     forward "/", PhoenixSwagger.Plug.SwaggerUI, otp_app: :chat_api, swagger_file: "swagger.json"
@@ -103,6 +109,12 @@ defmodule ChatApiWeb.Router do
     post("/event_subscriptions/verify", EventSubscriptionController, :verify)
   end
 
+  scope "/api/v1", ChatApiWeb do
+    pipe_through([:public_api])
+
+    get("/me", SessionController, :me)
+  end
+
   # Enables LiveDashboard only for development
   #
   # If you want to use the LiveDashboard in production, you should put