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From: Rainer Weikusat <rweikusat@mssgmbh.com>
Newsgroups: comp.os.linux.development.apps
Subject: Re: Program hanging on recv()
Date: Mon, 04 Feb 2013 19:43:19 +0000
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Ramon <ramif_47.invalid@yahoo.co.uk> writes:
> What I'm actually doing is just downloading an XML page to memory
> using the HTTP
> protocol. (e.g. http://weather.yahooapis.com/forecastrss?w=2502265)

[...]

> *Question*:  Is it possible to know the size of the page to download
> beforehand?

If you're only interested in using the TCP connection for a single
request-reply exchange, send a HTTP1.0 request without a Connection:
header or with Connection: close as connection header and call
shutdown(sockfd, SHUT_WR) on you socket after sending the complete
request. The server is then required/ supposed to mark the end of the
reply by closing the connection so you can just read until EOF.

Otherwise, there are (AFAIK) two additional cases to deal with:

	- length of the content is provided in form a a Content-Length
          header

	- so-called 'chunked transfer coding' (reply is send in chunks
          each of which is preceded by a chunk length)