Tighten up surface requirements to only apply to ARM-based systems

[KeyserSosa]

Alos fixup unit tests to cover more of the current set of common browsers as base cases. The consensus seems to be that only ARM based Windows RT surfaces (2-3 years old now) should really be considered tablets. One corroborating repository for that assessment:

https://github.com/serbanghita/Mobile-Detect/blob/master/Mobile_Detect.php#L227

I'm equally happy to just remove that change as it seems small edge case.

[RyanJarv]

We attempted to use this devicedetect repo but ran into issues with several users getting the mobile version of the site. After a while of searching I found a Windows 8.1 Chrome User-Agent matching the old regular expression here. Below is the User-agent.

Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.36

I'm not sure why the semi-colon in the regular expression is being ignored but this does in fact match and can be tested on varnish 4.1 with the following varnishtest.

varnishtest "Device detection"

server s1 {
   rxreq
   txresp
} -start

varnish v1 -vcl+backend {
  sub vcl_recv {
    if (req.http.User-Agent ~ "Touch.+Tablet PC" ||
      req.http.User-Agent ~ "Windows NT [0-9.]+; [ARM;|WOW64;|Win64; x64]" ) {
      set req.http.X-UA-Device = "tablet-microsoft";
    } else {
      set req.http.X-UA-Device = "Something-Else";
    }
  }
  sub vcl_deliver {
    set resp.http.X-UA-Device = req.http.X-UA-Device;
  }
} -start

client c1 {
  txreq -hdr "User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.36"
  rxresp
  expect resp.http.X-UA-Device != "tablet-microsoft"
} -run

I hope this can get merged in soon. Right now this device detection seems to be broken for 64 bit chrome windows users.

[RyanJarv]

Looking at the original regex again I imagine it was supposed to be this:

if (req.http.User-Agent ~ "Touch.+Tablet PC" ||
      req.http.User-Agent ~ "Windows NT [0-9.]+; (ARM;|WOW64;|Win64; x64)" )

Not the parenthesis instead of square brackets. But either way if this is overly broad then it probably needs to be removed.

[fgsch]

@KeyserSosa I think you should commit this. Whether matching on ARM alone (and not something else as Mobile-Detect does) can be tweaked later. As things stand at the moment this is broken for some users as reported by @RyanJarv .

[KeyserSosa]

Merged