Does a HTTP resource that accepts range requests always specify content-length? <p>Before starting a range request, I first check if it is supported using a HEAD request. Normally I get back something like this:</p> <pre><code>curl -X HEAD -i http://bits.wikimedia.org/images/wikimedia-button.png HTTP/1.1 200 OK ... Content-Length: 2426 Accept-Ranges: bytes ... </code></pre> <p>Is the Content-Length guaranteed per the HTTP/1.1 specification in this case? I can't find a definitive answer but it seems like I would need to know the Content-Length before I do a Range request.</p>