Logging into a website through google and scraping data from it

Hello,

In Swift, I want to be able to log into a website that uses a Google account to log in and scrape page text from it.

Let me explain.

I'm trying to build an app that will run in the background and periodically pull page text from a website to see if its changed. If its changed I will recieve a notification, etc. That's the base of the app. This wouldn't be too hard, but the problem is: The website I need to get to requires you to login first. Now I'm not trying to hack into the website because I don't have access. If I log in using my google account (which is what it prompts me to do), it lets me in just fine.

If I log out of the website in Safari, and reload the page, I come to a screen with a list of my three google accounts. I can log in with the third one in the list and proceed to the website.

I've already followed a Stack Overflow post that said how to scrape the content of a website and produced this code:

let url = NSURL(string: "\website url here\")
        let request = URLRequest(url: url as! URL)
        let task = URLSession.shared.dataTask(with: request) {(data, response, error) in
            var myString = String(NSString(data: data!, encoding: String.Encoding.utf8.rawValue)!)
            print(myString)
        }
        task.resume()

This code will gather the HTML from the website page specificed and print it to the console. I tried applying this code to apple.com (not the website I want to use obviously) and it printed the HTML code for apple's website, which contained some page text, but not all by the looks of it. I then tried scraping the website I want to get to. I copied and pasted the link which it took me to after I logged in. When it printed to the console, I found the words "Google" and "Account" everywhere meaning it had not bypassed the login screen.

What I want my app to do is, however neccessary (whether it be creating a WebKit view, something similar to my example up there, or something completely different), bypass the Google page by logging in to that third account or somehow clicking it, then take all the text on the page it redirects to and convert it to a String to then be parsed, etc.

How would I go about doing this?