Did you find any assistance on this with the Alteryx community either? I am replying here to bring the post back to the top of the 'recent discussions' but it woudl be great to know if you have located a solution. Sadly, I am not familiar enough with Alteryx to assist here.
I haven’t made many REST API calls to Tableau, however I have been working on REST API calls to another app from Alteryx and I highly recommend adding Postman to your toolkit. I figure out what the REST calls need to look like in Postman and then translate that into Alteryx. It helps me by separating the “what exactly do I need to send to the remote app to get it do what I want” question from the “how do I need to configure Alteryx” question.
I did indeed find a solution
1) Copy/pasting the Request Body provided in the Tableau Documentation into a Formula tool to build the "payload" manually. Here's what it looks like.
The Subscription-Subject and Content-Type parameters are simple pieces of text (The former will be the subject of the e-mail notification the Tableau Server sends out, the latter is either View or Workbook, depending on what you are subscribing people too). The content-id (unique ID of the view), schedule-id (unique ID of the specific schedule you are subscribing people too), and user-id (unique ID of each Tableau User) parameters are each obtained by making different REST API calls, which can be found in the Tableau REST API documentation
2) Switching my Download tool a Custom POST request (Just select Custom in the API call options and specify POST manually). You than also need to tick 'Take Query String/Body from Field' and select the payload you built in the formula tool.
3) Using only X-Auth-Code as a Header (No need for a Content-Type header). You obtain this code using the Publish to Tableau Server Tool, you have to select Request Authorization token to obtain it and use it in your download tool to 'talk' to the server.
Was a real shot in the dark as neither Tableau nor Alteryx provided any documentation on this!