I co-wrangle a few Cisco wireless LAN controllers (WLCs) that manage a variety of SSIDs, including some that authenticate users on a landing page. Webauth pages are in an interesting niche: they’re among the pages many users see daily, and yet their design quality does not tend to be proportional to their prominence. That shouldn’t be a surprise — the set intersection of Cisco wizards and web frontend designers is pretty small.
I’m not a Cisco wizard — but I could play one on TV, and somehow it has fallen to me to breathe new life into campus webauth landing pages. I wanted to use responsive design for optimal performance across phones, tablets, and computers, and images in SVG format that would look delightful at all zoom levels and pixel densities. My landing pages worked perfectly as served from an nginx testing server, but SVG logos failed to appear when uploaded as part of a webauth bundle and served on a testing SSID on the WLCs.
The WLCs were indeed serving the SVGs, but careful sleuthing in the network
monitor du jour (in Firefox: Ctrl-Shift-k –> Network) showed that the WLCs were
setting the Content-Type header of the SVG responses to
application/octet-stream, rather than the appropriate
Browsers were thus obeying the WLC web servers’ instructions to not show the
SVGs as images. There is no reliable client-side (and client-friendly) way to
get around this.
Eventually, I decided to replace the SVGs with PNGs of about double the
horizontal and vertical resolution specified for the logo
spans in CSS, which
results in acceptable appearance when slightly zoomed in. It’s pretty silly that
Cisco’s WLCs have such a limited set of supported MIME types.