Verifying webhook for Paddle

popo63301 · February 7, 2023, 1:57pm

Hello !

I’m trying to implement my own webhook verification function for paddle but I’m stuck at the step of SHA1 verification.

I’m trying to translate JS code from this repo example to Elixir:

The file: verify-paddle-webhook/index.js at 9f7d9d3cf8afe6ba28724496f26ecad165992202 · daveagill/verify-paddle-webhook · GitHub

The test file: verify-paddle-webhook/index.test.js at master · daveagill/verify-paddle-webhook · GitHub

I really struggle to understand the :crypto module documentation in Erlang.

Can anyone help ?

benlime · February 7, 2023, 2:15pm

Hey there. I recently wrote a Twitter thread about that. Maybe this helps?

Here is probably the part you are most interested in. Validating the paddle hook in paddle_signature.ex:

gist.github.com

https://gist.github.com/benvp/ae32016ca3449c977326ebce420ed493#file-paddle_signature-ex

_paddle_script.html.eex

<script src="https://cdn.paddle.com/paddle/paddle.js"></script>

<%= if vendor_id = Application.get_env(:my_app, :paddle)[:vendor_id] do %>
  <%= if Application.get_env(:my_app, :paddle)[:sandbox] do %>
    <script type="text/javascript">
      Paddle.Environment.set("sandbox");
      Paddle.Setup({ vendor: <%= vendor_id %> });
    </script>
  <% else %>
    <script type="text/javascript">

This file has been truncated. show original

license.ex

defmodule MyApp.Licensing.License do
  use Ecto.Schema

  import Ecto.Changeset

  alias MyApp.Accounts.User

  @primary_key false
  @foreign_key_type :binary_id
  schema "licenses" do

This file has been truncated. show original

paddle_controller.ex

defmodule MyAppWeb.PaddleController do
  use MyAppWeb, :controller

  require Logger

  alias MyApp.{Accounts, Licensing}
  alias MyApp.Licensing.License

  def webhook(conn, %{"alert_name" => "subscription_created"} = params) do
    user = fetch_user(params)

This file has been truncated. show original

There are more than three files. show original

popo63301 · February 7, 2023, 2:28pm

Indeed ! It really helped me solve my problem !

Thanks a lot !!!