File Uploads Using the Req Elixir Library

file_upload_using_req.exs

defmodule Uploader do
  @moduledoc """
  Source: https://samrat.me/til-file-uploads-using-the-req-elixir-library
  v0.4.5 of Req don't support file upload. Might as well use multipart
  """
  def transcribe_audio(file_path, token) do
    model = "whisper-1"
    filename = Path.basename(file_path)
    {:ok, file_contents} = File.read(file_path)

    multipart =
      Multipart.new()
      |> Multipart.add_part(Multipart.Part.text_field(model, "model"))
      |> Multipart.add_part(
        Multipart.Part.file_content_field(filename, file_contents, :file, filename: filename)
      )

    content_length = Multipart.content_length(multipart)
    content_type = Multipart.content_type(multipart, "multipart/form-data")

    headers = [
      {"authorization", "Bearer #{token}"},
      {"Content-Type", content_type},
      {"Content-Length", to_string(content_length)}
    ]

    Req.post(
      "https://api.openai.com/v1/audio/transcriptions",
      headers: headers,
      body: Multipart.body_stream(multipart)
    )
  end
end