Add 'urn' to allowed protocols

[geekysoft]

'urn' should be the safest protocol to allow on the planet as it doesn’t do much, except act as an identifier in various XML schemes.

the_guid() currently uses esc_url() as a default filter, meaning urn:uuid:<hash> can’t be used as a guid in feeds ithout first allowing the urn protocol. The Atom feed standard shows most examples with a urn:uuid used as the ID. (IDs in Atom must be URIs so using esc_url() still makes perfect sense.)

The attach patch adds the urn protocol to the list of allowed protocols. (See RFC 2141 for details on the protocol schema.)

Work-around: print( get_the_guid() ); doesn’t apply any default filters like the_guid() does.

[ocean90]

@geekysoft Thanks for the ticket and the patch, looks good to me. The function needs only a new changelog entry for the new protocol, see [32346] for 'webcal'.

[geekysoft]

@ocean90, I’m sorry for not responding earlier. This went into my Spam folder. Do you still need me revise the patch to include the changelog entry? What version number should I use?

[jorbin]

Updated patch to be from the root.

@ocean90 Can you take a look?

[ocean90]

In 38686:

Add 'urn' to the list of URI protocols whitelisted by default.

Props geekysoft, jorbin.
Fixes #37300.