Non-literal host names returned for some auto-discovered WSD devices

[alexpevzner]

Some devices (for now, only Pantum MFPs know to have such a behaviour) when being automatically discovered using WS-Discovery in the WSD mode report their endpoint URLs using device names, not IP addresses. I.e., http://Pantum-1C6FA7:43001/43001, not http://192.168.0.47:43001/43001

It is not good for several reasons:

• things become slower. because symbolic (non-literal) URL needs to be resolved every time it is being used
• the name that device uses is not necessarily resolvable via DNS (depends on device configuration; often default name is used)
• it adds extra dependency on local DNS which makes things more complex and less predictable

As for now, the preferred behaviour would be to resolve host names in these URLs during discovery. For now it looks most reasonable to use Avahi directly to resolve these names via MDNS. However some practical experience is required; may be in the future we will prefer to use standard libc resolver for this purpose or make things configurable

[alexpevzner]

The following commit has addressed this issue: https://github.com/alexpevzner/sane-airscan/commit/6cc94e9e3e1932d97690a45f5461ad64e057ebc3

[alexpevzner]

Fixed