[Wikitech-l] ULS and caching

[Denny Vrandečić]

Hi all,

Wikidata is planned as a multilingual resource, and we are using ULS
for switching languages. ULS is pretty cool, if you have not tried it
out yet, you definitively should.
ULS works great if you are a logged in user.
ULS on Wikidata does not work so well right now if you are not logged
in. Due to caching issues, the system sometimes switches your language
randomly.

There is a bug with quite some discussion going on:


There is a changeset to ULS providing one solution:


There seems to be an agreement that the solution could fix the issue
for now with Wikidata, but it is unclear if this will scale to the
Wikipedias. This is a call for some input and attention to anyone who
can help resolve the issue.

So far huge thanks to Daniel K., Mark, Niklas, Katie, Siebrand, Faidon
for pushing for solutions.

Cheers,
Denny


-- 
Project director Wikidata
Wikimedia Deutschland e.V. | Obentrautstr. 72 | 10963 Berlin
Tel. +49-30-219 158 26-0 | http://wikimedia.de

Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e.V.
Eingetragen im Vereinsregister des Amtsgerichts Berlin-Charlottenburg
unter der Nummer 23855 B. Als gemeinnützig anerkannt durch das
Finanzamt für Körperschaften I Berlin, Steuernummer 27/681/51985.

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Re: [Wikitech-l] ULS and caching

[Yury Katkov]

This ULS? https://www.mediawiki.org/wiki/Universal_Language_Selector

-
Yury Katkov, WikiVote




On Tue, Nov 6, 2012 at 11:46 PM, Denny Vrandečić <
denny.vrande...@wikimedia.de> wrote:

> Hi all,
>
> Wikidata is planned as a multilingual resource, and we are using ULS
> for switching languages. ULS is pretty cool, if you have not tried it
> out yet, you definitively should.
> ULS works great if you are a logged in user.
> ULS on Wikidata does not work so well right now if you are not logged
> in. Due to caching issues, the system sometimes switches your language
> randomly.
>
> There is a bug with quite some discussion going on:
> 
>
> There is a changeset to ULS providing one solution:
> 
>
> There seems to be an agreement that the solution could fix the issue
> for now with Wikidata, but it is unclear if this will scale to the
> Wikipedias. This is a call for some input and attention to anyone who
> can help resolve the issue.
>
> So far huge thanks to Daniel K., Mark, Niklas, Katie, Siebrand, Faidon
> for pushing for solutions.
>
> Cheers,
> Denny
>
>
> --
> Project director Wikidata
> Wikimedia Deutschland e.V. | Obentrautstr. 72 | 10963 Berlin
> Tel. +49-30-219 158 26-0 | http://wikimedia.de
>
> Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e.V.
> Eingetragen im Vereinsregister des Amtsgerichts Berlin-Charlottenburg
> unter der Nummer 23855 B. Als gemeinnützig anerkannt durch das
> Finanzamt für Körperschaften I Berlin, Steuernummer 27/681/51985.
>
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> Wikitech-l mailing list
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> https://lists.wikimedia.org/mailman/listinfo/wikitech-l
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Re: [Wikitech-l] ULS and caching

[Tim Starling]

On 07/11/12 07:46, Denny Vrandečić wrote:
> There is a changeset to ULS providing one solution:
> 

As I said on the changeset, adding Vary: Cookie doesn't actually do
anything, but if you did make it do something, the result would be
essentially no caching, since there is client-side code deployed which
sets random cookies for all anonymous users.

The variant feature has much the same problem, and they solved it by
putting the language code in the URL, and then purging all possible
language URLs when a page is changed. Then only the
language-independent URLs need to send Vary: Accept-Language. I think
that is the best solution here, also.

Maybe it would be possible to vary on the value of the ULS language
cookie, but it would require patches to Squid and Varnish. Maybe you
could get away with just patching every client-side extension to use
local storage instead of cookies, but the result would be pretty
fragile since apparently, all our frontend developers love $.cookie
and use it by reflex.

-- Tim Starling


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Re: [Wikitech-l] ULS and caching

[Ori Livneh]

On Tuesday, November 6, 2012 at 4:22 PM, Tim Starling wrote:

> Maybe it would be possible to vary on the value of the ULS language
> cookie, but it would require patches to Squid and Varnish.

I don't know about Squid, but there are all manner of ways you could attack 
this problem with Varnish. Overriding vcl_hash lets you customize how a cache 
key is constructed from a request. It's usually just hostname + URL, but you 
can add any string to the hash:


sub vcl_hash {
if (req.http.Cookie ~ "language") {
hash_data(regsub(req.http.Cookie, "^.*(language=[^;]+).*$", "\1"));
}
}



--
Ori Livneh
o...@wikimedia.org



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