Re: [squid-users] Metalink (XML mirror & checksum list) downloads with Squid?

Anthony Bryan wrote:
> Hello,
>
> I figured this would be a good place to ask about Metalink downloads
> with proxies.
>
> Metalinks are XML files that list the mirrors a file is available
> from, checksums, sometimes signatures, and other useful info. They're
> frequently used for large files like ISOs. I've included a sample
> metalink at the end of this message.
>
> I am not familiar with how proxies work internally. If a file listed
> in a metalink is already cached, but a different URI is used then I
> assume it won't be recognized and will be requested again since it
> seems to be an uncached file?

Yes.

> I'm wondering if the checksums in a metalink or something else could
> be used to see if the file is the same or not. Are there other
> possible Metalink issues with proxies?

No. Proxies usually make decisions based on the *request* HTTP headers
and client source IP. Before the object is ever received.
Which for example may be nothing more than:
"
   GET http://example.com/meta.dat HTTP/1.1
   Host: example.com
"
As you can see, no checksum present. Even if the object *after
retrieval* may turn out to be a duplicate, its far too late.

> We are working on an Internet Draft for Metalink at
> http://tools.ietf.org/html/draft-bryan-metalink-03 .
>
> Also, I noticed 2 minor typos on 2 pages:
>
> "...provide static, dymanic and streaming content" on
> http://www.squid-cache.org/Intro/
>
> dynamic
>
> "...during the developmen and not for general users." on
> http://www.squid-cache.org/Support/mailing-lists.dyn
>
> development

Thank you. Fixed.

Amos

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