Ruby Rest-client keeps correcting the uri - ruby-on-rails

Question

I'm using rest-client to make a post request to a certain address. Unfortunately rest-client keeps correcting the web adres from 'https' to 'http'. Which then gives back an error.
I already looked at the documentation whether this maybe was a setting for the gem. Anyone knows how I can 'force' rest-client to access the desired address.
Thx in advance!
used code is:
uri = 'https://sandbox.api.online.unit4.nl/V19/OAuth/Token'
payload = {
code: params[:code],
client_id: '#{#client_id}',
client_secret: '#{#client_secret}',
redirect_uri: '#{#client_redirect_url}',
grant_type: 'authorization_code'
}
response = RestClient::Request.execute(method: :post, url: uri, headers: {params: payload})
curl:
> GET /V19/OAuth/Token HTTP/1.1
> Host: sandbox.api.online.unit4.nl
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 400 Bad Request
< content-length: 27
< content-type: application/json; charset=utf-8
< date: Wed, 06 Dec 2017 15:21:44 GMT
< p3p: CP="NON CUR OTPi OUR NOR UNI"
< server: Microsoft-IIS/7.5
< x-aspnetmvc-version: 5.2
< cache-control: no-cache, no-store, max-age=0, must-revalidate
< access-control-allow-origin: *
< x-powered-by: ASP.NET
< x-aspnet-version: 4.0.30319
< pragma: no-cache
< Set-Cookie: PD_STATEFUL_88eb7504-dfe9-11e2-8624-005056af4a32=sandbox.api.online.unit4.nl; Path=/
< Set-Cookie: LB_online_unit4=1493375404.20480.0000; path=/

Answer 1

Could be that your variables aren't getting interpolated. With single quotes '#{#variable}' doesn't work. Try switching the single quotes to double quotes ('' => ""). What is happening is that instead of sending the actual client id and secret, you are sending the string #{#client_id}.
Try
uri = 'https://sandbox.api.online.unit4.nl/V19/OAuth/Token'
payload = {
code: params[:code],
client_id: #client_id,
client_secret: #client_secret,
redirect_uri: #client_redirect_url,
grant_type: 'authorization_code'
}
response = RestClient::Request.execute(method: :post, url: uri, headers: {params: payload})