Funny that it mentions twisted (briefly). I last used tcpflow not long ago to debug some issues in twisted proxy. Twisted has two quirks that make it slightly less compatible/forgiving with the web at large than most browsers.
1. It lowercases headers, such that Cookie: becomes cookie:. Technically, the standard says they are case insensitive.
2. When reading responses, it strictly looks for \r\n line endings. \n will not cut. Standard does say \r\n is the only acceptable ending.
Guess which web server violates both of these rules? The one in arc that powers Hacker News. Figuring out why my proxy worked with every website except HN probably wouldn't have been possible without tcpflow.
1. It lowercases headers, such that Cookie: becomes cookie:. Technically, the standard says they are case insensitive.
2. When reading responses, it strictly looks for \r\n line endings. \n will not cut. Standard does say \r\n is the only acceptable ending.
Guess which web server violates both of these rules? The one in arc that powers Hacker News. Figuring out why my proxy worked with every website except HN probably wouldn't have been possible without tcpflow.