Alter a stream with trumpet, how to get content-length header in http.Response right?

Question

I have a nodejs http server running and I want to alter content on specific sites (kind of my own private ad-blocker). I decided to do this with trumpet . Now the problem is, when trumpet injects the new content and pipes it to the http Response (http.IncomingMessage), the headers['content-length'] value is no more valid.

Some browsers do not seem to care (Chrome / Firefox on W7), others crash immediatly (Safari on iPad). I tried erasing the content-length header alltogether, with similar outcome (Safari waiting forever).

How can I set the content-length of the response right, after switching contents? I found harmon , but I just need this last bit, so harmon felt like too much overhead. Or is it not that trivial?

Answer 1

If you do not know how big your response will be when you send the headers (the case here), you need to use chunked transfer encoding .

Node should default to chunked transfer encoding if you do not specify any Content-Length . Either remove the code that's setting the Content-Length header or try res.removeHeader('Content-Length') .