[OpenSIPS-Users] mid_register and its possible bad actions with De-REGISTER

[Dmitry Ponomaryov]

Hello, opensips community, let's imagine default situations where we 
have dynamic users who can move and change FREQUENTLY! ip-address on 
phone, and re-send the registration, and at the same time we have in the 
configs:

mid_registrar_save("location","c1f");

in this case, we receive with any new registration from the user, the 
old registration will be deleted:

PQsendQuery(delete from location where contact_id=...) 
mid_registrar:reg_tm_cback: >> [REPLY] UNREGISTER !

this is in Contact throttling, reflected by contact_id.

and each deletion of a contact from the location table leads to a 
De-REGISTER, and a new register, is such a De-REGISTER needed?? which if 
this all happens in throttling mode, and OpenSIPS knows about all 
contacts, and let the final server be Asterisk , the main thing is to 
send INVITE to OpenSIPS for further work.

All this to say, it might make sense to add the ability to disable this 
De-REGISTER, because with a new registration, we will still send it a 
registration with an updated contact before the main registrar times 
out, and there will be no problems, that is, for example, the following 
settings:

modparam("mid_registrar", "outgoing_expires", 600) 
modparam("mid_registrar", "default_expires", 300)

 From doc mid_registrar:

A common occurrence is for some SIP User Agents to lose their network 
connection (especially when dealing with mobile devices), hence they do 
not properly de-register from the mid-registrar. In this case, in order 
to avoid stale registrations on the main registrar (which contains SIP 
contacts with greatly extended lifetimes!), the mid-registrar will 
appropriately generate De-REGISTER requests and remove these contacts 
from the main registrar's location service as soon as it considers them 
to have expired.

Thank you in advance!