Google’s John Mueller said it is good practice to specify a rel=canonical. John said this is regardless of framework and is espesially true when “you have preferences regarding the URL shown.”

He said this on Twitter the other day:

A lot of CMS platforms do this by default, but if you have something custom – you can do it as well.

Just don’t do it wrong because if you specify the wrong canonical, it can cause serious damage.

Forum discussion at Twitter.