Re: [PATCH] core: add internet connectivity check

[Marcel Holtmann <marcel holtmann org>]

Hi Thomas,

> >>>> i just want to summarize the discussion about the response handling so
> >>>> we can decide which solution we want to use.
> >>>> mentioned solutions are:
> >>>>
> >>>> 1) check http status-response 204 (or any other) (chromiumos method)
> >>>> 2) check content for a specific http header (connman method)
> >>>> 3) check start of content (implemented in patch V3)
> >>>> 4) check complete content
> >>>> 5) check http status-response 200 (creates false positives for hotspots)
> >>>> 6) check content with a regex (tie us into a specific regex lib)
> >>>>
> >>>> 5+6 are already declined.
> >>>>
> >>>> i prefer solution 3 because it's more flexible than 1) and produce fewer
> >>>> traffic than 2).
> >>>
> >>> actually 2) would produce fewer traffic than 3) since the HTTP headers
> >>> are transmitted before the content.
> >>
> >> You are right. i mixed up http headers with html headers.
> >>
> >>> If you just want some stupid check, then looking at the headers is
> >>> simpler since otherwise you have to deal with HTTP 1.0 vs 1.1 and have
> >>> to have support for chunked encoding.
> >>
> >> i'm not sure but i think libsoup handles 1.0/1.1 and chunked encoding.
> >>
> >> i like the idea of a plain text file because it's more easy to setup on
> >> server side than http headers.
> >
> > creating server side HTTP headers is as simple as plain text files. We
> > decided for the HTTP headers since it a lot more logical then doing some
> > random plain file comparison.
> 
> if you have a managed server (without root access) i think it's not so 
> easy to send http headers but it's simple to deliver a plain text file.

it is as simple with a managed server. We are using Apache + PHP and for
example it can be done like this:

header('X-ConnMan-Status: online');

> >>> However if your long term goal is WISPr support, then you have to look
> >>> at the whole page anyway. There is no guarantee that the WISPr XML is at
> >>> the beginning. Some providers actually just attach it to the end.
> >>
> >> personally i don't care about WISPr. I just want to know if i have a
> >> working internet connection.
> >
> > Doing this without also handling WISPr seems rather pointless. I prefer
> > my system to automatically log me into a hotspot if I have access
> > credentials for it.
> 
> why do you think that's pointless?
> eg i have a embedded device with an usb-gadget (detected as ethernet 
> device). when i connect my pc with the device over usb, the device has 
> no internet connection. but when i configure my pc to forward some 
> traffic from the device, the device has internet connection. for this 
> usecase it's very nice to check the connectivity.
> the device can do different task if a connection is available.

I would solve that entirely different, but fair enough.

Regards

Marcel