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well, as I said the document root is c:/xampp/htdocs/sub_crud. Within the sub_crud dir
c:
xampp  
  htdocs
    sub_crud   << document root
       application  
           controllers
               Configure.php   <<main controller
A user of the main program enters localhost in the browser and the Configure controller runs. Eventually this thing will be hosted on Google Cloud but I am still developing the app.

I am not sure how to architect this.

My Chrome Extension has two functions: a) login b)submit
Login sends an email string to my localhost. The program on localhost gets the email address looks it up in my database and sends back some JSON data that the Extension uses to populate its popup.html. How should the executable that gets the email string be configured? This being a CI centric place I have had some comments to just use a controller and a model. I could probably set up a route in my Configure controller called login that can be called like this from the Extension

xhr.open("GET", "http://localhost/login/".emailaddress, true);

So this would use the same controller as my regular application (which is a Grocery Crud app). It is a little strange to me to use a CI application as a daemon, but I guess it could work? As long as every user running my regular old Configure app is running a separate process. In the "olden days" we would spawn threads for something like this, but I really want to do this as simply as modernly possible. So to recap, when a call is made to xhr.open("GET", "http://localhost/login/".emailaddress, true) a new copy of my controller will run the "login route". Right? Can I start execution on a new CI process from a xhr.open?

proof that an old dog can learn new tricks