[avahi] Client Browser questions

[Nathanael D. Noblet]

On 04/12/2011 11:44 PM, Rajesh Sai T wrote:
> Hi Nathan,
>
> Even im looking out for a potential possibility to know if any
> device publishing the service has been removed from LAN and all rest of
> devices get a REMOVE notification so that respective devices can update
> their cache. If any new device comes up, we get BROWSER_NEW event in
> browser_callback but there isnt any event for REMOVE. Could you please
> just share your idea how could we achieve this?


Well there are two callbacks, one for browse, which gets events like 
AVAHI_BROWSER_NEW and AVAHI_BROWSER_REMOVE.

when you get BROWSER_NEW you get a new resolver which takes the new 
event and resolves it to a hostname etc. and that gets returned in a 
browser_resolve_callback.

So from looking at how avahi-discover does it, I added to my app 'global 
object' that gets passed to all callbacks a GList services;

the avahi-discover has a Hashtable of servicetypes & services, but I 
don't need all service types, just the one, so all I have is a GList.

in the browse_resolve_callback, I create a structure, with the service 
name, domain, host and interface and protocol and append it to my list 
of services.

Then I have a function that given the list of the services checks for a 
duplicate. It does this with

s->interface == interface && s->protocol == protocol && 
avahi_domain_equal(s->service, service_name) && 
avahi_domain_equal(s->domain, domain_name)

which was learnt from looking at avahi-discover similar test.

 From there in the browse_callback, when I get a AVAHI_BROWSER_REMOVE 
event I call this getService function that loops over the GList and 
returns the matching record, then do what I need to remove it from my app...

-- 
Nathanael d. Noblet
t 403.875.4613