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Re: GET with offset ?

From: Claus André Färber <claus@faerber.muc.de>
Date: Mon, 14 Sep 1998 10:00:26 +0100 (BST)
To: http-wg@hplb.hpl.hp.com
Message-Id: <70pLlgXZcDB@faerber.muc.de>
Tristan Savatier <tristan@mpegtv.com> schrieb:
> Thanks. Now I see how to do a GET with range request.
> Now, another question:
> Is there a way to specify the offset or range with the http: URL
> syntax ?
> i.e. something like http://host/dir/file@range=0,500

No, but media types can define how to access parts of a document.  
Examples:

http://host/foo.html#section2.1.1
http://host/foo.pdf#page123
http://host/foo.mpeg#2m03s04f   (hypothetical)

What is missing is a method to only access the parts that are really  
needed, i.e. if the part referred to is #page123, the server determines  
which byte ranges that are and returns them. However, this depends on  
the media type.
For some media types, you _can_ retrieve the header (of the file, not  
the http header!) after determining the media type and calculate the  
offset of the part you want to retrieve.

An HTTP method by which the client can have the server/proxy parse the  
message content and retrieve the parts' names with the corresponding  
byteranges could be useful:

- RANGES /foo.html HTTP/1.1
+ 300 HTTP/1.1 Ok.
+ Content-Type: message/byterangeinfo
+
+ * 0-480
+ #sec1 123-245
+ #sec2 245-345
+ #sec3 345-467

--
Claus Andre Faerber <http://www.muc.de/~cfaerber/> Fax: +49_8061_3361
PGP: ID=1024/527CADCD FP=12 20 49 F3 E1 04 9E 9E  25 56 69 A5 C6 A0 C9 DC
Received on Friday, 18 September 1998 06:28:21 EDT

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