Put API v2 rate limit token to cookies

apps/block_scout_web/config/config.exs

@@ -12,7 +12,8 @@ config :block_scout_web,
   cookie_domain: System.get_env("SESSION_COOKIE_DOMAIN"),
   # 604800 seconds, 1 week
   session_cookie_ttl: 60 * 60 * 24 * 7,
-  invalid_session_key: "invalid_session"
+  invalid_session_key: "invalid_session",
+  api_v2_temp_token_key: "api_v2_temp_client_key"
 
 config :block_scout_web,
   admin_panel_enabled: System.get_env("ADMIN_PANEL_ENABLED", "") == "true"

apps/block_scout_web/lib/block_scout_web/api_key_v2_router.ex

@@ -9,8 +9,6 @@ defmodule BlockScoutWeb.APIKeyV2Router do
     plug(Logger, application: :api_v2)
     plug(:accepts, ["json"])
     plug(CheckApiV2)
-    plug(:fetch_session)
-    plug(:protect_from_forgery)
   end
 
   scope "/", as: :api_v2 do
@@ -18,6 +16,6 @@ defmodule BlockScoutWeb.APIKeyV2Router do
 
     alias BlockScoutWeb.API.V2
 
-    get("/", V2.APIKeyController, :get_key)
+    post("/", V2.APIKeyController, :get_key)
   end
 end

apps/block_scout_web/lib/block_scout_web/controllers/api/v2/api_key_controller.ex

@@ -2,10 +2,13 @@ defmodule BlockScoutWeb.API.V2.APIKeyController do
   use BlockScoutWeb, :controller
 
   alias BlockScoutWeb.AccessHelper
-  alias Plug.Crypto
+
+  @api_v2_temp_token_key Application.compile_env(:block_scout_web, :api_v2_temp_token_key)
 
   action_fallback(BlockScoutWeb.API.V2.FallbackController)
 
+  plug(:fetch_cookies, signed: [@api_v2_temp_token_key])
+
   def get_key(conn, params) do
     helper = Application.get_env(:block_scout_web, :captcha_helper)
     ttl = Application.get_env(:block_scout_web, :api_rate_limit)[:api_v2_token_ttl_seconds]
@@ -14,11 +17,14 @@ defmodule BlockScoutWeb.API.V2.APIKeyController do
          {:recaptcha, false} <- {:recaptcha, is_nil(recaptcha_response)},
          {:recaptcha, true} <- {:recaptcha, helper.recaptcha_passed?(recaptcha_response)} do
       conn
+      |> put_resp_cookie(@api_v2_temp_token_key, %{ip: AccessHelper.conn_to_ip_string(conn)},
+        max_age: ttl,
+        sign: true,
+        same_site: "Lax",
+        domain: Application.get_env(:block_scout_web, :cookie_domain)
+      )
       |> json(%{
-        key:
-          Crypto.sign(conn.secret_key_base, conn.secret_key_base, %{ip: AccessHelper.conn_to_ip_string(conn)},
-            max_age: ttl
-          )
+        message: "OK"
       })
     end
   end

apps/block_scout_web/lib/block_scout_web/views/access_helper.ex

@@ -11,7 +11,7 @@ defmodule BlockScoutWeb.AccessHelper do
   alias BlockScoutWeb.WebRouter.Helpers
   alias Explorer.AccessHelper
   alias Explorer.Account.Api.Key, as: ApiKey
-  alias Plug.{Conn, Crypto}
+  alias Plug.Conn
 
   alias RemoteIp
 
@@ -77,7 +77,7 @@ defmodule BlockScoutWeb.AccessHelper do
     ip_string = conn_to_ip_string(conn)
 
     plan = get_plan(conn.query_params)
-    token = get_ui_v2_token(conn, conn.query_params, ip_string)
+    token = get_ui_v2_token(conn, ip_string)
 
     user_agent = get_user_agent(conn)
 
@@ -167,18 +167,19 @@ defmodule BlockScoutWeb.AccessHelper do
     to_string(:inet_parse.ntoa(ip))
   end
 
-  defp get_ui_v2_token(conn, %{"token" => token}, ip_string) do
-    case is_api_v2_request?(conn) && Crypto.verify(conn.secret_key_base, conn.secret_key_base, token) do
-      {:ok, %{ip: ^ip_string}} ->
-        token
+  defp get_ui_v2_token(conn, ip_string) do
+    api_v2_temp_token_key = Application.get_env(:block_scout_web, :api_v2_temp_token_key)
+    conn = Conn.fetch_cookies(conn, signed: [api_v2_temp_token_key])
+
+    case is_api_v2_request?(conn) && conn.cookies[api_v2_temp_token_key] do
+      %{ip: ^ip_string} ->
+        conn.req_cookies[api_v2_temp_token_key]
 
       _ ->
         nil
     end
   end
 
-  defp get_ui_v2_token(_conn, _params, _ip_string), do: nil
-
   defp get_user_agent(conn) do
     case Conn.get_req_header(conn, "user-agent") do
       [agent] ->