Preflight error on device (ios)

I cannot find a way using HttpClient to get around Preflight error when trying to upload a photo to an API from an iOS device. Some background:

  1. I have no control over the server/API (in case it’s a CORS issue)
  2. The API is configured to accept only multipart/form-data

For the rest of the app, I’ve been using ionic-native http, which has worked great - except it seems it doesn’t support multipart/form-data. For this single call, I tried using angular HttpClient, which is resulting in the preflight errors.

Code is very vanilla … I can post anything anyone would like to see, but it’s nothing out of the ordinary.

I’ve done a lot of Googling on this, and the solutions so far are

  1. CORS issue, reconfigure the server (not an option for me)
  2. switch to ionic-native http (due to content-type, not an option for me, unless someone has found a way to make that work)
  3. downgrade web kit view - doesn’t seem like a very good solution

Has anyone had success doing something similar?