How to read data when HttpResponse has no Content-Length

Question

Hi, support

Unusually, some sites (SugarSync) send data without a Content-Length header in the Http response when passing through a proxy server(Fiddler).

In this case, if I read data from the Response Stream, a Connection Closed error occurs immediately. (Of course it will)

Even if KeepAlive is set, the server sends data with a Connection: closed in the Header and closes it immediately after sending.

However, it seems impossible, but is there a way to handle it, even if it is a trick?

Thank you

Answer 1

Hi,

Actually, with "Connection: closed", the server is supposed to close the connection immediately after sending the data, and that should be handled by HttpResponse without issues.

However, it's possible that the server closes the connection in a wrong way. For example, when HTTPS is used, the connection should be closed by sending the closenotify alert message, because a lack of that would open the connection to truncation man-in-the-middle attacks, where the client could be tricked into accepting incomplete data without being able to detect that. So perhaps the lack of closenotify is actually the issue with SugarSync?

Please post the error message you get, or rather a debug log - that should help us to figure out what's actually going on, and hopefully suggest a workaround for that particular issue.

Comments

Thanks for your answer.

I simply assumed that the problem was caused by the lack of Content-Length Header information.
But it was a Connection-related issue.

When I connected through Fiddler classic or directly, there was still no Content-Length information in the Header, and all headers were the same.

Therefore, it seems that Fiddler is not handling the connection properly.
So I think it can be concluded as a Fiddler issue.
I can send you the log if you need it.

Thank you