DNSSD Browser UI Service Type helper function: _mailto._tcp

[adam-burns]

helper function for_mailto._tcp useful for browser UI to reolve & connect to service instances.

should map URL schema to mailto: (note no forward slashes)
take number from a TXT attribute, "to" ie to=[email protected]
and map into format mailto:

this well known mapping will work for any browser on any platform that has a schema handler defined for mailto:
mobile phones (android & ios) auto-associate this with their phone email apps

example: mailto:[email protected]

note cc, bcc & body elements as descibed in mailto should be defined in TXT record.

For any browsing domain that wishes to define one or more _mailto._tcp service type instances, a PTR record of (eg)

_services._dns-sd._udp. PTR _mailto._tcp.

must exist.

For any browsing domain that has has no _mailto._tcp service types existing or last remaining has been deleted, then PTR record of

_services._dns-sd._udp. PTR _mailto._tcp.

should be deleted.

this is useful for example in giving email contact details for map points.