Need Assistance in Configuring Varnish to Retain and Ignore Unique Parameter in Request URL while caching

[Guillaume Quintard]

Thanks, so, to make things clean you are going to need to use a couple of
vmods, which means being able to compile them first:
- https://github.com/otto-de/libvmod-uuid as Geoff offered
- https://github.com/Dridi/libvmod-querystring that will allow easy
manipulation of the querystring

unfortunately, the install-vmod tool that is bundled into the Varnish
docker image isn't able to cleanly compile/install them. I'll have a look
this week-end if I can, or at least I'll open a ticket on
https://github.com/varnish/docker-varnish

But, if you are able to install those two, then your life is easy:
- once you receive a request, you can start by creating a unique ID,
which'll be the the vcl equivalent of `uuidgen | sed -E
's/(\w+)-(\w+)-(\w+)-(\w+).*/\1\2\3\4/'` (without having testing it,
probably `regsub(uuid.uuid_v4(), "s/(\w+)-(\w+)-(\w+)-(\w+).*",
"\1\2\3\4/"`)
- then just add/replace the parameter in the querystring with
vmod_querystring

and...that's about it?

Problem is getting the vmods to compile/install which I can help with this
week-end. There's black magic that you can do using regex to manipulate
querystring, but it's a terrible idea.

-- 
Guillaume Quintard


On Wed, May 31, 2023 at 6:48 PM Uday Kumar <uday.polu at indiamart.com> wrote:

>
> Does it need to be unique? can't we just get away with
>> "aaaaaaaaaaaaaaaaaaaa"?
>>
>
> Our Requirements:
> 1. New Parameter should be *appended *to already existing parameters in
> Query String. (should not replace entire query string)
> 2. Parameter Value *Must be Unique for each request* (ideally unique
> randomness is preferred)
> 3. Allowed Characters are Alphanumeric which are *URL safe* [can be
> lowercase, uppercase in case of alphabets]
> 4. Characters can be repeated in parameter value EX: Gn4lT*Y*gBgpPaRi6hw6
> *Y*S (here, Y is repeated) But as mentioned above the value must be
> unique as a whole.
>
> Ex: Parameter value for 1st request can be "Gn4lT*Y*gBgpPaRi6hw6*Y*S",
>                                         2nd request can be
> "G34lTYgBgpPaRi6hyaaF" and so on
>
>
> Thanks & Regards
> Uday Kumar
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://www.varnish-cache.org/lists/pipermail/varnish-misc/attachments/20230531/c78458d0/attachment.html>