img "srcset" attribute urls are not proxyfied

[mattvick]

Loading the following page: http://kalkulackaenergie.com/

Through the proxy: https://www.optimcore.com/proxy/http://kalkulackaenergie.com/

Causes Mixed Content errors because image source urls within an img tag srcset attribute are loaded directly, over http. These urls should be proxyfied.

[nfriedly]

Oh, wow, I didn't realize srcset worked now - cool!

Do you think you can write a test and a fix and send me a PR?

For the test, add a line to test/source/index.html and test/expected/index.html and then the existing test infrastructure will find it; and then the fix can probably just be a tweak to the regex at lib/url-prefixer.js#L22

[emilhem]

It's easy to write a test but fixing srcset seems harder.
Since srcset can contain many urls its tricky to fix.
References:
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Img#Example_4_Using_the_srcset_and_sizes_attributes
https://webkit.org/demos/srcset/

[nfriedly]

Oh, yikes. Maybe this isn't such a good first bug...

[nfriedly]

This might help: https://www.npmjs.com/package/srcset