Fix the documentation for the sign parameter

[MathieuLegault1]

Even thought the documentation says that you should include the leading "/" in practice you need to exclude it.

  def generate_signature(url, config) do
    uri = URI.parse(url)
    url_path = uri.path
    url_path = String.trim_leading(url_path, config.path <> "/") # This is removing the leading /

    url_query =
      uri.query
      |> URI.decode_query()
      |> Enum.sort_by(fn {key, _} -> key end)
      |> Map.new()
      |> Map.drop(["sign"])
      |> URI.encode_query()

    Base.url_encode64(:crypto.mac(:hmac, :sha256, config.url_signature_key, url_path <> url_query))
  end

[simonprev]

That’s weird because it breaks the imaginary lib: https://github.com/h2non/imaginary?tab=readme-ov-file#url-signature.

I think we should maintain this contract by fixing this lib and making a major version release.

Can you add a test that shows the bug?

[MathieuLegault1]

Is there a reason we want to stay compliant with h2non/imaginary ? I don't see any mention of that lib in the plug_image_processing project. But yeah I don't mind changing this lib to keep it. I'll add a test for it !

[MathieuLegault1]

I've added a test that demonstrate that the "/" is excluded. I'll change the code (and the test) after you give me a 👍 that we want that !

[remi]

Looks like it’s in the repository’s description and tags only:

But we should definitely make it more obvious in README.md 😁