At Sun, 26 Oct 2014 11:40:31 -0700, Jason Fesler wrote:
On Sun, Oct 26, 2014 at 10:52 AM, Niall O'Reilly <niall.oreilly@ucd.ie> wrote:
In the case mentioned, it looks as if application error HTTP 404 is being interpreted as indicating IPv6 network target unreachable. Isn't this a layering misinterpretation?
Yes. But I have limits on what I can do in JavaScript, without invoking browser specific or even operating system specific code, or depending on plugins. I can (as far as I know) only detect success, failure, and timeout. Above all, I want the site to operate purely on simple clean javascript that works on any popular browser, and ideally, even the unpopular javascript-enabled browsers.
I fear that "simple clean javascript that works on any popular browser" may be an unattainable goal. The jQuery library attempts to provide a uniform abstraction layer above the particular behaviour of individual browsers. I've found it useful, but my experience is limited, so I can't say whether it achieves all you'll need.
FWIW: I always check IPv4 as a control measure. I only complain when IPv6 fails but IPv4 worked. This catches the case of apache httpd being down; it catches power down; it doesn't catch more subtle problems. When the control is down, I discount it from the list of failures (grey instead of red; and the ISP test in particular stops counting it).
Not perfect; but if you can help me improve on this in a way that keeps my goal of simple javascript, I'm very much interested in your ideas. In some cases, it may be as simple as expertise (since JavaScript is not my "native tongue", so to speak).
We both share that pedigree! 8-)
Thanks for the feedback! And thanks for taking the time to read the document. A lot of people have put a lot of time into that document already. I'm hoping ultimately the community finds the document (and the site) useful.
Thanks for revealing more of the picture to me. ATB Niall