Pre-Code request for a squid helper for "time quota"

Hello squid developers,

I would like to extend squid so that an administrator can define a
maximum time for web access for a given time period. This could be used
for parents limiting the time to use the internet. E.g. I would like to
define something like:

joe:unlimited
mary:unlimited
littlejoe:2h / 1day
littlemary:4h/1week

I know, that squid already allows to limit the access time (e.g. Monday
from 2pm to 4pm), but this is to unflexible for children. They should
decide on there own WHEN to use the internet but only up to a given
"time quota".

Question 1: do you know of something similar?

Question 2: I would would like to implement this in the following way.
Is this OK or do you have any tips?

It could be an external_acl helper very similar to the existing "squid
session" helper. There would be an additional configuration file as
described above. The module would be included in squid.conf with a

external_acl_type time_quota ttl=60,negative_ttl=60 %LOGIN
/usr/local/squid/libexec/time_quota -f /usr/local/squid/etc/time_quota.conf
acl AclName external time_qouta

It would count how many minutes each user has already used and store
that in memory or a database. As long as their is enough time left, it
would respond with OK, otherwise with ERR until the limit is reset.

Question 3: Assuming that I code it in a way you like it, are you
willing to include this into squid? I would transfer any license which
is needed.

Thanks for developing squid and your precious time.

Kind regards,
  Till

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