Allow whitespace before protocols.

[benubois]

Hi @rgrove,

Thanks for an excellent library!

I recently received a bug report on Feedbin about a broken image. The source in the XML looked like:

<img src="
http://img.thedailywtf.com/images/14/q4/e141/Pic-2.png" />

But after it was sanitized it looked like:

<img>

It appears that any attribute that is checked for a valid protocol will be stripped if it contains leading whitespace.

Not sure if this is the right place to address this. The other idea I had was to allow for a regex when specifying allowed protocols like:

protocols: {
  'img' => {'src' => [/\A\s*http/i]}
}

[rgrove]

@benubois Thanks! I've merged and released 3.0.4 with this fix.

I'm a huge Feedbin fan, btw. Had no idea you were using Sanitize. :)

[benubois]

Excellent! Happy to hear you're a Feedbin fan.

Yeah, sanitize is perfect for safely displaying content from an RSS feed 😄