Add the ability to specify a custom port to which requests will be redirected.

[A]

For example, I have expressjs app that listen 3000 port instead 80.

[mistakster]

Actually, there is no issue with port numbers other than 80. Try to fetch page using curl

curl "http://127.0.0.1:3000"

HTML page appears blazing fast.

Now run throttle-proxy with very low speed limit: throttle-proxy -s 1000 and make same request.

curl -x 127.0.0.1:3128 "http://127.0.0.1:3000"

As you can see, the terminal window updates very slowly.

If you fetch page using browser then please check your network setting. It seems that proxy is misconfigured.

[A]

Mea culpa, I tried to write something like 0.0.0.0:3128 in my web-browser. And I did not understand that it is a real proxy. Now established it as a proxy for the browser and it worked.