Cross-Domain Caching

[Per Buer]

Look at the headers. If there are two numbers next on the X-Varnish header
it's a cache hit. One number - cache miss.


On Wed, Jun 11, 2014 at 10:07 PM, Diego Rabatone <diraol at diraol.eng.br>
wrote:

> Thanks Per,
>
> I have read the link you suggested and it made all more clear to me now.
>
> It looks that my varnish is now "working", but I don't know if it is
> caching or now, how to test if it is a cached version or if it is just a
> redirect?
>
> Thanks again.
>
>
> --------------------------------
> Diego Rabatone Oliveira
> diraol(arroba)diraol(ponto)eng(ponto)br
> Identica: (@diraol) http://identi.ca/diraol
> Twitter: @diraol
>
>
> 2014-06-11 16:26 GMT-03:00 Per Buer <perbu at varnish-software.com>:
>
>  Hi Diego.
>>
>> What you need to understand is how the server which you are embedding the
>> content from works. It will not serve up the right content unless you give
>> it the right Host: header (
>> https://www.varnish-software.com/blog/getting-virtual-hosts-right-varnish-cache
>> explain how virtual hosts actually works).
>>
>> The thing you are missing is something like this:
>>
>> sub vlc_recv {
>>   if (req.http.host ~ "infographics.estadaodados.com") {
>>      set req.http.host = "example.com";
>>      # could also override req.url here - but better to keep req.url the
>> same (for simplicity).
>>      set req.backend_hint = infograph;
>>   }
>>
>>
>>
>> On Wed, Jun 11, 2014 at 8:10 PM, Diego Rabatone <diraol at diraol.eng.br>
>> wrote:
>>
>>> Hi James and Per,
>>>
>>> thank you very much for answering my question.
>>>
>>> First of all, I have the permission to embed the content. All embeds are
>>> from websites that are offer the service of building data visualizations
>>> and infographics, me and my team use them to build our products and they
>>> all have embeding options.
>>>
>>> I like the option to only revalidate the contet, instead of refetching
>>> it, but I didn't understand completly how could I do it Per.
>>>
>>> I will try and example, tell me if I'm making any conecptual mistake.
>>>
>>> My cached domain is: *estadaodados.com <http://estadaodados.com>* ,
>>> this is were I have full control and where my Varnish is.
>>>
>>> On *estadaodados.com/iframe <http://estadaodados.com/iframe>* I want to
>>> embed, using an Iframe, a page from *example.com <http://example.com>*,
>>> exactly this page: *example.com/123* <http://example.com/123>
>>>
>>> So, instead of using *<iframe src="http://example.com/123
>>> <http://example.com/123>"></iframe>*
>>> I should set *example.com <http://example.com>* as a *backend* on my
>>> varnish with:
>>>
>>> backend infograph {
>>>     .host="example.com"
>>> }
>>>
>>> And set this vcl_recv rule:
>>>
>>> sub vlc_recv {
>>>   if (req.http.host ~ "infographics.estadaodados.com") {
>>>      set req.backend_hint = example.com
>>>   }
>>>
>>> And then use the iframe with:
>>>
>>>
>>> *<iframe src="infographics.estadaodados.com/123
>>> <http://infographics.estadaodados.com/123>"></iframe> *
>>>
>>> That's it?
>>>
>>> Thanks for your attention,
>>>
>>> Best,
>>>
>>>
>>> --------------------------------
>>> Diego Rabatone Oliveira
>>> diraol(arroba)diraol(ponto)eng(ponto)br
>>> Identica: (@diraol) http://identi.ca/diraol
>>> Twitter: @diraol
>>>
>>>
>>> 2014-06-10 3:55 GMT-03:00 Per Buer <perbu at varnish-software.com>:
>>>
>>>  Hi Diego,
>>>>
>>>>
>>>> On Tue, Jun 10, 2014 at 1:24 AM, Diego Rabatone <diraol at diraol.eng.br>
>>>> wrote:
>>>>
>>>>> Hi friends,
>>>>>
>>>>> I am new at the caching World, and I have looked for some solution to
>>>>> cross-domain caching, but I have not found any solution.
>>>>>
>>>>> I have a blog that embed some dataviz webservices, and I want to cache
>>>>> this content that I insert using Iframes.
>>>>> The blog is: http://blog.estadaodados.com there is any way of doing
>>>>> this?
>>>>>
>>>>
>>>> Absolutely. It is a pretty good way to make sure that the content you
>>>> embed performs well in addition to lessening the load on the server you are
>>>> embedding content from.
>>>>
>>>>
>>>>> At this moment I have a Varnish + nginx + php-fpm setup on a dev
>>>>> server (not the link that I posted), and it seems to be working ok, but
>>>>> there is no caching of the Iframes.
>>>>>
>>>>
>>>> No. This is expected. In order to cache those iframes you would need to
>>>> set up the server you embedding content from as a backend on your varnish
>>>> and preferably give it a new hostname. Then, in the vcl_recv you replace
>>>> req.http.host to the original hostname and set the backend. Then regular
>>>> caching rules will be applied. In Varnish 4.0 you could set the cache time
>>>> to one hour and you could add a keep of maybe a couple of hours. That will
>>>> enable IMS so you wouldn't have to refetch the content, only revalidate it.
>>>>
>>>>
>>>> As James said, should make sure you have the authors permission, but if
>>>> you do it through Varnish at least there won't be much of a impact on their
>>>> server when you do this.
>>>>
>>>> Cheers,
>>>>
>>>> Per.
>>>>
>>>> --
>>>>  <http://www.varnish-software.com/> *Per Buer*
>>>> CTO | Varnish Software
>>>> Phone: +47 958 39 117 | Skype: per.buer
>>>> We Make Websites Fly!
>>>>
>>>> Winner of the Red Herring Top 100 Global Award 2013
>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>>  <http://www.varnish-software.com/> *Per Buer*
>> CTO | Varnish Software
>> Phone: +47 958 39 117 | Skype: per.buer
>> We Make Websites Fly!
>>
>> Winner of the Red Herring Top 100 Global Award 2013
>>
>>
>>
>


-- 
 <http://www.varnish-software.com/> *Per Buer*
CTO | Varnish Software
Phone: +47 958 39 117 | Skype: per.buer
We Make Websites Fly!

Winner of the Red Herring Top 100 Global Award 2013
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