Fix the RDFa markup for number of comments on teasers [#694994]

The RDFa markup for the number of comments in teaser mode is:

<div about="/node/12">
  <ul>
    <li>
      <a content="4" property="sioc:num_replies" href="/node/12#comments">4 comments</a>
    </li>
  </ul>
</div>

I initially thought it would create the triple
</node/12> sioc:num_replies "4" .

but it turns out the RDFa parser I use generates
</node/12#comments> sioc:num_replies "4" .

What's happening is that the href URI is set as new subject because there are no rel/rev (due to the RDFa parsing rule 4). Our options are either to:
- add about="/node/12" in the a tag
- add rel="" in the a tag

Although it's less self explanatory, I would choose the empty rel which would perform slightly better - no value to check_plain() in drupal_attributes() - and generate a bit less extra markup (with appropriate documentation in rdf.module).

(see related thread on the RDFa mailing list).

Comment	File	Size	Author
#8	rdf_694994_4.patch	2.86 KB	Stefan Freudenberg
#8
#6	rdf_694994_3.patch	2.95 KB	Stefan Freudenberg
#6
#4	rdf_694994_2.patch	2.86 KB	Stefan Freudenberg
#4
#2	rdf_694994.patch	926 bytes	Stefan Freudenberg
#2

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Comments

Comment #1

scor CreditAttribution: scor commented 25 January 2010 at 18:27

Issue tags:

+RDF, +RDFa

tagging

Comment #2

Stefan Freudenberg CreditAttribution: Stefan Freudenberg commented 6 April 2010 at 14:58

Status:

Active

» Needs review

File	Size
rdf_694994.patch	926 bytes

Here's a patch that adds the empty rel attribute to the comment count links.

Comment #3

scor CreditAttribution: scor commented 6 April 2010 at 15:33

Status:

Needs review

» Needs work

We need a comment to explain why we need to add this empty rel, something like:
According to the RDFa processing rule #4 triggered the lack of @rel/@rev attribute, a new subject URI will be set from the @href value. We want to trigger rule #5 and for that reason set an empty @rel attribute. (with a link to http://www.w3.org/TR/rdfa-syntax/#sec_5.5.)

A test for that empty @rel will also be nice :)

Comment #4

Stefan Freudenberg CreditAttribution: Stefan Freudenberg commented 7 April 2010 at 23:35

File	Size
rdf_694994_2.patch	2.86 KB

Added a comment and a test.

Comment #5

Stefan Freudenberg CreditAttribution: Stefan Freudenberg commented 7 April 2010 at 23:38

Status:

Needs work

» Needs review

Comment #6

Stefan Freudenberg CreditAttribution: Stefan Freudenberg commented 8 April 2010 at 13:33

File	Size
rdf_694994_3.patch	2.95 KB

Removed trailing whitespace.

Comment #7

scor CreditAttribution: scor commented 8 April 2010 at 14:15

This patch works. The test fail when the empty @rel hunk is not there, and works otherwise, so this is RTBC after some minor docs tweaks below (leaving needs review as this is minor).

+++ modules/rdf/rdf.module	8 Apr 2010 12:42:24 -0000
@@ -483,6 +483,12 @@ function rdf_preprocess_node(&$variables
+      // According to RDFa parsing rule number 4 a new subject URI is created

a comma between "number 4" and "a new..." would improve the read flow.

+++ modules/rdf/rdf.module	8 Apr 2010 12:42:24 -0000
@@ -483,6 +483,12 @@ function rdf_preprocess_node(&$variables
+      // the original node URL from the about attribute of the container we

parent container to be more explicit.

+++ modules/rdf/rdf.module	8 Apr 2010 12:42:24 -0000
@@ -483,6 +483,12 @@ function rdf_preprocess_node(&$variables
+      // from the href attribute if no rel/rev attribute is present.  To get

+++ modules/rdf/rdf.module	8 Apr 2010 12:42:24 -0000
@@ -483,6 +483,12 @@ function rdf_preprocess_node(&$variables
+      // set an empty rel attribute which triggers rule number 5.  See

We don't put double space after the end of a sentence.