[wp-trac] [WordPress Trac] #37240: Remove schemes from dns-prefetch resource hint outputs

[WordPress Trac]

#37240: Remove schemes from dns-prefetch resource hint outputs
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 Reporter:  niallkennedy                |       Owner:  voldemortensen
     Type:  defect (bug)                |      Status:  reviewing
 Priority:  normal                      |   Milestone:  4.6
Component:  General                     |     Version:  trunk
 Severity:  normal                      |  Resolution:
 Keywords:  has-patch needs-unit-tests  |     Focuses:  performance
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Changes (by swissspidy):

 * keywords:  has-patch has-unit-tests commit => has-patch needs-unit-tests


Comment:

 The [https://w3c.github.io/resource-hints/ specification] isn't clear
 about the schemes and uses protocol-relative URLs or relative URLs
 everywhere in the examples.

 For Chromium, it doesn't matter whether it's `//` or `http://`:

 > The double slashes indicate that the URL starts with a host name (as
 specified in RFC 1808). It is equivalent (but unnecessary) to use a full
 URL such as "http://host_name_to_prefetch.com/".

 Source: https://www.chromium.org/developers/design-documents/dns-
 prefetching

 That's also the impression I got when looking at the Webkit source code.

 The only benefit I see is that we'd be able to filter out duplicates
 (which the browser would probably do anyway). As per the ticket
 description, wordpress.org, http://wordpress.org, https://wordpress.org
 should all have the same DNS lookup and therefore only need 1 entry.

 We need a unit test to cover this.

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Ticket URL: <https://core.trac.wordpress.org/ticket/37240#comment:6>
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