microdot.route(...) decorator details

[matthimue]

I'm running microdot on an esp32, it's a great framework!!!
I have a generic question trying to understand in the code of 'microdot.route()...'

My question is, how does the decorator route(...) work, without having the function as parameter 'f' but it is used in decorated(f) to register (same for get,del, patch,....). For after_request(self, f) or before_request(self, f) this is different. What insights am I missing here to understand from decorator usage.

def route(self, url_pattern, methods=None):
def decorated(f):
self.url_map.append(
([m.upper() for m in (methods or ['GET'])],
URLPattern(url_pattern), f, '', None))
return f
return decorated

[miguelgrinberg]

Decorators are a standard feature of the Python language. I have written a series of articles on my blog that explain how they work: https://blog.miguelgrinberg.com/post/the-ultimate-guide-to-python-decorators-part-i-function-registration. The route decorator you are interested in is one of the most advanced, and is covered in the 3rd article in the series.