I am working on a project that requires the use of the Dropbox API to create personalized file requests for survey users to upload their supporting documents to my Dropbox Account. 

The workflow is that the user works on their survey, if based on their answers they need to submit documents, a Dropbox file request is created for that user via the Dropbox API and then the link is displayed to the user as part of the end of survey message (with a copy sent via email)

Due to Dropbox using short lived tokens for authentication (4 hours) every time the survey is accessed, we need to get a new token as users will have two weeks to submit their survey and documents. 

So, I am trying to get a “refreshed token” via the Dropbox API. The documentation for their HTTP SDK provides the documentation/sample code as a cURL statement (shown below) which I have tested, and it works on my computer (for purposes of security I replaced the sensitive values with Embedded Data fields. 

curl https://api.dropbox.com/oauth2/token  -d grant_type=refresh_token -d refresh_token=${e://Field/DBX_AUTH_REFRESH_TOKEN} -u ${e://Field/DBX_AUTH_APP_KEY}:${e://Field/DBX_AUTH_APP_SECRET}

So, the issue is how do I translate this into the Qualtrics Web Services prompts in Survey Flow. 

All guidance is appreciated.