[squid-users] hsc-dynamic-cache: relied on storeID rules? Removed in 3.5.20?

[Eliezer Croitoru]

Hey Linda,

As the pathcer\author of StoreID I will try to clarify what might seems odd.
StoreID is a "static" rule which is one of the squid cache fundamentals.
The feature is the option to tweak this internal cache object ID.
This is a very static feature and will not be changed for a very long time from now on.
Most of the public helpers I have seen are very "simple" and rely on very simple things.
The main idea is that the admin can know and predict what would be the StoreID.
It's like "knowing" what the kid is going to say next from the past experience with him.
In a similar way StoreID allows an admin that can predict that a specific URL will contain the same content as another one that was previously cached.
In a more simple way, it gives that admin the option to run a "de-duplication" script.

But since many systems these days are aware of the option to predict what would be the next url(think about an exe or other binary that can be replaced on-the-fly\in-transit) the developers changed and change(like a Diffe Hellman) their way of transporting content to the end client.
Due to this "Diffe Hellman" feature that many added it makes the more simple scripts useless since the developers became much smarter.
And back to the analogy, the kid grows and talks in a certain language.
Now the kids is much more mature after couple years and he became smart enough so you would need to actually answer the question "where do kids come from" or some other questions.
Then the answer can be creative enough to leave the child with a satisfying and a good one. If you "miss" this opportunity and will answer a very non-realistic answer(compared to the kid's age) the next time he would demand from you a more demanding answer and eventually if you would answer too many bad responses he will eventually go and research by himself in other and maybe a more reliable sources.
(the above analogy is what gave squid a very bad reputation by many admins)

Today Squid-Cache is smart enough to at-least answer the right answer for a demanding client even if the admin does something wrong in his StoreID helper.
Indeed you will see TCP_MISS and it won't cache but this is only since the admin might have the illusion that an encrypted content can be predicted when a Diffie  Helman cryptography is creating the plain url's these days.

Hope It helped,
Eliezer

* For youtube to be cached the best way is to learn more about content adaptation and to have a look at some youtube video downloaders scripts.

----
Eliezer Croitoru
Linux System Administrator
Mobile: +972-5-28704261
Email: eliezer at ngtech.co.il



-----Original Message-----
From: squid-users [mailto:squid-users-bounces at lists.squid-cache.org] On Behalf Of L A Walsh
Sent: Monday, March 27, 2017 10:26 PM
To: Yuri Voinov <yvoinov at gmail.com>
Cc: squid-users at squid-cache.org
Subject: [squid-users] hsc-dynamic-cache: relied on storeID rules? Removed in 3.5.20?

This caught my attention as my housemate tends to watch alot of
youtube videos, and caching some of them might speed up their
access, so was trying to understand what was meant in your post:

Yuri Voinov wrote:
> Things are changed in the web on regular basis. Nothing permanent in the
> world.
>
> So, store ID rules lost relevance and no longer work.
>   
----
    Is the problem that "Store ID rules lost relevance" caused by a
change from squid 3.5.19 -> 3.5.20?

    That doesn't sound so much like a change on the web, but a change
in squid.

    Were storeID rules removed in 3.5.20?  If that's the case,
what might have replaced them?

@Eduardo: am I to understand that this plugin worked in 3.5.19, but
not in 3.5.20 and above?  (trying to get the versions right)

Also, Eduardo -- what specific features above 3.5.19 were you hoping
to include by upgrading?  I.e. is 3.5.19 not working for you for some
reason?  It might be easier to cherry pick changes that you needed from
some later version back into 3.5.19 if some major feature
(like storeID rules?) was removed after that version...

Thanks Yuri!
Linda


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