Splash return embedded response

I am looking to return an embedded response from a website. This website makes it very difficult to reach this embedded response without javascript so I am hoping to use splash. I am not interested in returning the rendered HTML, but rather one embedded response. Below is a screenshot of the exact response that I am looking to get back from splash.

This response returns a JSON object to the site to render, I would like the raw JSON returned from this response, how do I do this in Lua?

Turns out this is a bit tricky. The following is the kludge I have found to do this:

Splash call with LUA script, called from Scrapy:

scrpitBusinessUnits = """
            function main(splash, args)
                splash.request_body_enabled = true
                splash.response_body_enabled = true
                assert(splash:go(args.url))
                assert(splash:wait(18))
                splash:runjs('document.getElementById("RESP_INQA_WK_BUSINESS_UNIT$prompt").click();')
                assert(splash:wait(20))
                return {
                    har = splash:har(),
                }
            end
        """
        yield SplashRequest(
            url=self.start_urls[0],
            callback=self.parse, 
            endpoint='execute',
            magic_response=True,
            meta={'handle_httpstatus_all': True},
            args={'lua_source': scrpitBusinessUnits,'timeout':90,'images':0}, 
        )

This script works by returning the HAR file of the whole page load, it is key to set splash.request_body_enabled = true and splash.response_body_enabled = true to get the actual response content in the HAR file.

The HAR file is just a glorified JSON object with a different name... so:

def parse(self, response):
        harData = json.loads(response.text)
        responseData = harData['har']['log']['entries']
        ...
        # Splash appears to base64 encode large content fields, 
        # you may have to decode the field to load it properly
        bisData = base64.b64decode(bisData['content']['text']) 

From there you can search the JSON object for the exact embedded response.

I really dont think this is a very efficient method, but it works.