chain of responsibility pattern in your command linewith the virtual environment activestart the serverwith hello_world_server py set as the application to handle requests uwsgi --http : --wsgi-file hello_world_server py if you point your browser to hello world in the window congratulationsyou have your very own web server runningyou could even deploy it on serverpoint url at itand let the world send requests to it what we want to do next is see how the middleware fits into the flow from request to response by building it from the ground up since the server is already up and runninglet' add function to check if the user token is set in the headers we are going to follow convention that is used by number of bigger apis you might find online uthentication headers the idea is that the client includes an authorization headerwhere the header value is set to the word basic followed by spacefollowed by base -encoded string the string that gets encoded has the following formusername:passwordwhich will be used to identify and verify the user on the system before we continue building up the functionalityit is important to note that by including the authentication header whenever you make call to the appand having the app check for the authorization headeryou remove the need for the app to keep track of which user is making the callsand instead you get to attach the user to the request when that request happens the easiest way to test url endpoints is to install tool like postman on your system it allows you to request urls from the app and interpret the results the free postman app can be downloaded hereonce the postman install concludesopen the app firstenter the same url you entered in your browser into the postman address bar and click send or press enter you should see hello world in the box at the bottom of the screen this tells you that postman is working and your app is still running