title: Close the tab from a Flask route
body: <p>I have a client (written in Python) that opens a new browser tab where the user can give OAuth2 permission to my application; they are then redirected to my site, on a Flask route, where I do some database operations, and then want to close the tab.</p>
  
  <p>As a Flask route, though, I need to return something - I've tried to see if there's a special return value to close the tab, but haven't found anything, and redirecting to a different page with JavaScript that tells the tab to close doesn't work (I'm guessing because you need the same script to have opened that tab).</p>
  
  <p>Is there any way to achieve this? The site is simply a front for a RESTful API, so has no real content to show - I'd like to avoid adding a landing page to instruct the user to close the tab themselves.</p>
  
  <p>EDIT: This is not a duplicate, as I am aware I cannot just open a page that closes itself - but the tab I open in the first place is opened from my client, and I am redirected to my own site; the question asks if, with these options as well, it becomes possible to close the tab.</p>