Register listener on the dbus interface to detect Avahi deamon restarts

[Supereg]

♻️ Current situation

As of now we don't detect restarts of Avahi Deamon and therefore remain without an advertising in this situation as explained in #923.

💡 Proposed solution

This PR fixes this by subscribing on the dbus StateChanged listener to detect avahi deamon restarts.

⚙️ Release Notes

• Properly recreate advertisements on restarts of avahi when using the avahi/dbus based advertiser.

➕ Additional Information

Testing

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Reviewer Nudging

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[Supereg]

@adriancable I'm currently unable to test this on a live machine. Could you verify, that this works as expected?

[coveralls]

Pull Request Test Coverage Report for Build 3358922347

• 10 of 28 (35.71%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.07%) to 51.913%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/lib/Advertiser.ts	10	28	35.71%

Files with Coverage Reduction	New Missed Lines	%
src/lib/Advertiser.ts	1	41.61%

Totals
Change from base Build 3358848225:	-0.07%
Covered Lines:	5820
Relevant Lines:	10247

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💛 - Coveralls

[adriancable]

Hi @Supereg - I'm on vacation until the end of the month and don't have access to a Linux machine to test. I'll happily have a look at the start of October if you can't find anyone else to test before that. Sorry!

[Supereg]

Well, I’m for a half a year in South Korea 😄 so let’s see, maybe I can start up one of my machines at home :) otherwise it will be October 🙃

[Supereg]

Have verified functionality (have restarted the daemon twice in the below log output). The re advertisement is also pretty fast:

DEBUG=HAP-NodeJS:Advertiser node dist/BridgedCore.js
  HAP-NodeJS:Advertiser Initializing HAP-NodeJS v0.10.4 ... +0ms
HAP-NodeJS fix/avahi-server-state-handling starting...
  HAP-NodeJS:Advertiser Detected Avahi over DBus interface running version 'avahi 0.7'. +0ms
  HAP-NodeJS:Advertiser Preparing Advertiser for 'Node Bridge 5BA5' using Avahi backend! +1ms
  HAP-NodeJS:Advertiser Starting to advertise 'Node Bridge 5BA5' using Avahi backend! +0ms
  HAP-NodeJS:Advertiser Found Avahi daemon to have restarted! +21s
  HAP-NodeJS:Advertiser Starting to advertise 'Node Bridge 5BA5' using Avahi backend! +0ms
  HAP-NodeJS:Advertiser Found Avahi daemon to have restarted! +15s
  HAP-NodeJS:Advertiser Starting to advertise 'Node Bridge 5BA5' using Avahi backend! +1ms

Calling avahi-browse afterwards yields positive results:

avahi-browse _hap._tcp --resolve
+ enp0s1 IPv6 Node Bridge 5BA5                              _hap._tcp            local
+ enp0s1 IPv4 Node Bridge 5BA5                              _hap._tcp            local
+     lo IPv4 Node Bridge 5BA5                              _hap._tcp            local
= enp0s1 IPv6 Node Bridge 5BA5                              _hap._tcp            local
   hostname = [primary.local]
   address = [fdfa:e7fa:e3cd:3065:5054:ff:febe:4642]
   port = [51826]
   txt = ["sh=73Llyg==" "ci=2" "sf=1" "s#=1" "pv=1.1" "md=Default-Model" "id=CC:22:3D:E3:CE:F6" "ff=0" "c#=3"]
= enp0s1 IPv4 Node Bridge 5BA5                              _hap._tcp            local
   hostname = [primary.local]
   address = [192.168.64.2]
   port = [51826]
   txt = ["sh=73Llyg==" "ci=2" "sf=1" "s#=1" "pv=1.1" "md=Default-Model" "id=CC:22:3D:E3:CE:F6" "ff=0" "c#=3"]
=     lo IPv4 Node Bridge 5BA5                              _hap._tcp            local
   hostname = [primary.local]
   address = [127.0.0.1]
   port = [51826]
   txt = ["sh=73Llyg==" "ci=2" "sf=1" "s#=1" "pv=1.1" "md=Default-Model" "id=CC:22:3D:E3:CE:F6" "ff=0" "c#=3"]