Should follow redirections but not cache against the redirected path

[uzyn]

I'm working on a flexible badge service, Umbo, that allows user to update the badge with any values.

Example: https://github.com/uzyn/umbo-weather/blob/master/README.md

To not reinvent the wheel, I'm relying on the great service, shields.io, for badge generation (for example: https://img.shields.io/badge/Singapore%2C%20Singapore-27.47%C2%B0C-yellow.svg)

For the example at umbo-weather, there's a background process that updates the value every 5 minutes.

The badge URL for Singapore weather is http://umbo.zynesis.com/singaporeio8gg0ok8ckwcck8.svg and it redirects to a different shields.io badge URL based on the value.

(Try going to http://umbo.zynesis.com/singaporeio8gg0ok8ckwcck8.svg in 5 minutes interval or so)

Camo, however, returns the final redirected URL and caches against that, of which the value never changes.

It would be great if Camo caches the original requesting URL instead. If not, what do you recommend that I should be doing for such service?

[atmos]

What headers are you setting? GitHub uses camo/fastly and respects caching headers.

[uzyn]

@atmos Here are the headers.

$ curl -i http://umbo.zynesis.com/singaporeio8gg0ok8ckwcck8.svg
HTTP/1.1 303 See Other
Server: Cowboy
Connection: keep-alive
X-Powered-By: Umbo 1.0.0 <umbo.io>
Access-Control-Allow-Origin: 
Access-Control-Allow-Credentials: 
Access-Control-Allow-Methods: 
Access-Control-Allow-Headers: 
Cache-Control: no-cache
Etag: 5732d227b1eaf5545a786fbdadaafccc812ab55f
Content-Type: image/svg+xml;charset=utf-8
Location: https://img.shields.io/badge/Singapore%2C%20Singapore-28.99%C2%B0C-yellow.svg
Set-Cookie: sails.sid=s%3AcZYsIV2YEOldVY8IG-WhoizndUGLiZfS.afH%2Fp%2Bg6eq904jAAFDGU%2Fq6DmdEdeyLx2aRo9GSV6Ac; Path=/; HttpOnly
Date: Sat, 11 Jul 2015 16:06:22 GMT
Transfer-Encoding: chunked
Via: 1.1 vegur

ETag is set too.

My case is rather unique in the sense that the redirected URL changes, ie, for the same URL:
http://umbo.zynesis.com/singaporeio8gg0ok8ckwcck8.svg

The generated badge is updated every 5 minutes, via different redirection URL, instead of via content changes.

[lifehome]

Camo, however, returns the final redirected URL and caches against that, of which the value never changes.

It would be great if Camo caches the original requesting URL instead. If not, what do you recommend that I should be doing for such service?

Why not both? Perhaps the hash could compare the Content-Length, then depends passing cached or renew the hash for being a new image?

[hiendv]

Sorry but anything new?
I'm sharing the same problem here: hiendv/hireable#1 (comment)