Scriptrunner Confluence Macro - Calling REST API to Watch Page and Descendants

[Julie Torres]

I'm trying to create a macro in Scriptrunner for Confluence Server/DataCenter, version 7.4.7. The macro would add a link that, when clicked, would add the current user as a watcher to the current page AND its descendants. 

To do this, I am trying to make an API call to Atlassian's REST API.

The following code works with the /rest/api/accessmode API, but when I call /rest/api/user/watch/content/{page-id}, the macro fails.

import com.atlassian.confluence.xhtml.api.XhtmlContent
import com.atlassian.sal.api.component.ComponentLocator
import groovy.xml.MarkupBuilder
import groovyx.net.http.ContentType
import groovyx.net.http.HTTPBuilder
import groovyx.net.http.Method

def httpBuilder = new HTTPBuilder("https://my-company-confluence-site.com")
def xhtmlContent = ComponentLocator.getComponent(XhtmlContent)

def rt = httpBuilder.request(Method.GET, ContentType.JSON) {
uri.path = "/rest/api/user/watch/content/162529323"
}

def writer = new StringWriter()
def builder = new MarkupBuilder(writer)

builder.div {
p {
yield(rt)
}
}

xhtmlContent.convertStorageToView(writer.toString(), context)

I'm modelling this macro after another macro - Watchlinks - that is being retired.

That macro is a link with the following URL. But when I try adding a link with that URL, it successfully watches the page and descendants, but doesn't allow me to un-watch the page. The link also has a couple of data tags, so there's surely some Javascript going on there too.

https://my-company-confluence-site.com/notificationpreferences/watch-descendants.action?pageId=162529323&atl_token=xxx

I also checked the normal Confluence watch button and the watch descendants checkbox. Those call the following API, which is not shown in the REST API docs:

https://my-company-confluence-site/rest/enterpriseNotificationsService/1.0/notifications/pageWatch/162529323/

My questions are:

1) Is calling the REST API the best way to handle this, or is there a better option?

2) Am I calling the right REST API?

3) Why is the call to /rest/api/user/watch/content/{page-id} failing / causing the macro not to load?

Any help is much appreciated.