Question

I tried to send a request within a Greasemonkey script, using the Range-header.
The requested site is kind of long and I know which parts I actually need, so I thought, instead of requesting the whole site to download I could just request the necessary 500 bytes to speed things up.

However, Range: bytes=0-500 always gives me the full website. I also tried Content-Range: bytes=0-500, which doesn’t work, and Content-Length:500 which isn’t allowed to set any more due to security-problems.

So, does anybody know, why it is like this?
I’m using Greasemonkey scripts:

 GM_xmlhttpRequest({
    method: 'GET',
    url: "http://colonel-strawberry.deviantart.com/",
     headers: {"Range": "bytes=0-500"}, 
    onload: function (responseDetails) {
      console.log(responseDetails);
    },
    onerror: function(responseDetails) {
      console.log("err:"+responseDetails);
    }
});

With response-header:

Date: Mon, 05 Nov 2012 17:11:42 GMT
Content-Encoding: gzip
Transfer-Encoding: chunked
P3P: policyref="/w3c/p3p.xml", CP="NOI DSP COR CURa OUR STP"
Connection: Keep-Alive
Server: Apache
Vary: Accept-Encoding
Content-Type: text/html
Cache-Control: private
Keep-Alive: timeout=45

Answer 1

The host colonel-strawberry.deviantart.com does not appear to support requests for byte ranges.

You would need to be requesting the data from a server that does support them.

(I tested by comparing curl -H "Range: bytes=50-60" $foo where $foo was first http://colonel-strawberry.deviantart.com and then where it was a URI on a server I do control).

Note the HTTP specification:

A server MAY ignore the Range header.