Why are Vapor GET requests being processed in the URL

Question

I am creating a Vapor server, but it is processing GET requests in the URL, when enter is not being pressed. See below for an example:

Suppose I have the code get('hello'), and whenever it is entered, it returns hello world in json format.

If I were to run the Vapor server, type localhost:8080/hello, and press enter in my browser, it will return {"hello":"world"}, which works as intended. On the console, it will print GET /hello, which works as intended. However, if I was to clear hello from the URL, I would have localhost:8080/ the output would be empty, printing GET / to the console. If I were to then append h to this: localhost:8080/h, then the URL will autocomplete to localhost:8080/hello because I entered it earlier, printing GET /hello to the console, before I have pressed enter in the URL.

Whenever I type text into the URL, it is sending a request to the Vapor server, and processing the request - even if I don't press enter to send the request.

Why is it doing this, and how can this be prevented?

Answer 1

Safari (and probably some other browsers) uses a pre-fetching feature. See 'Preload Top Hit in the background' in the Search section of Safari preferences. If enabled, your browser will send off GET requests at various times without your even being aware of it.

You can't stop this behaviour in the wide world, so you need to plan for it. GET endpoints shouldn't do any significant work, or change any model state. Put those sorts of endpoints behind a verb like POST.