实现API请求的正确方式

我正试图创建一个这样的请求,但使用ruby。

curl --request POST \
--url '{BASE_URL}/oauth2/token' \
--header 'Authorization: Basic {BASIC_CLIENT}' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data grant_type=client_credentials

我试着这样做:

require 'uri'
require 'net/http'

url = URI("https://api.userede.com.br/redelabs/oauth2/token")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = http.post(
  url,
  { 'grant_type' => 'client_credentials' }.to_json,
  { 'Authorization' => "Basic #{CLIENTID}", 'Content-Type' => 'application/x-www-form-urlencoded'}
)

但我得到了以下错误:

{\"error_description\":\"OAuth 2.0 Parameter: grant_type\",\"error\":\"invalid_request\",\"error_uri\":\"https://datatracker.ietf.org/doc/html/rfc6749#section-5.2\"}