Strip trailing spaces with canonical URLs

[matt]

Apparently a really common trailing 404 is %20s, like ​http://ma.tt/%20%20. We should strip these and redirects. It's from links like this:

<a href="http:/ma.tt/ ">

[markjaquith]

That shows a draft to me, and is_preview() is true, so Canonical code can't be run. Need to figure out what WP_Query is showing a draft in this situation.

[markjaquith]

Try this patch. Fixes it for pretty permalinks and default permalinks (in most situations). As with other things here, I've crafted it to look for specific circumstances, instead of hitting the problem with a big hammer. Let me know if you find a popular 404 case that isn't covered.

[markjaquith]

(In [8667]) Strip trailing spaces in URLs, redirect to canonical URL. fixes #7537

[DD32]

I'm getting constantly redirected to <page-requested/>? now, ie. its allways adding the Query to the end.

I'll attach a patch to fix it.

[markjaquith]

(In [9197]) Switch to using empty()/!empty() checks in Canonical. see #7537

[markjaquith]

Closing. Reopen if issues remain.