Filtering of password protected posts

[paddelboot]

Goal:
to query for password protected posts only or to remove all password protected posts from a query.

Current solution:
Modify the query SQL by using the 'posts_where' filter as suggested here: ​http://stackoverflow.com/questions/7538959/how-to-exclude-password-protected-posts-in-wordpress-loop

Suggested solution:
Make it possible to modify a parameter via 'pre_get_posts' or 'request' - filter, i.e. $query->set( 'post_password', TRUE ).

[ocean90]

See ​http://codex.wordpress.org/Reporting_Bugs#Trac_Keywords for allowed keywords.

[nacin]

I could go for post_password as a query variable with these possible values:

• null (ignore)
• false (only posts without passwords)
• true (only posts with passwords)
• a string (posts with this exact password)

In practice, this kind of type-checking is not particularly feasible in WP_Query, unfortunately. Would have to be two different query vars, such as password_exists and post_password. So for now, something like password_exists or has_password seems like a good approach.

[robmiller]

I've added a patch that allows querying for password-protected posts in WP_Query.

It adds a query var called "has_password"; if it's truthy, password-protected posts will be returned; if it's falsey, public posts will be returned.

[robmiller]

Add has_password var to WP_Query

[wonderboymusic]

Modified the patch to do all of the things @nacin said

[nacin]

WP_Query + query variables are not really designed for type-checking, so I'm not sure about 20308.diff​. Let's consider has_password => true|false|null. And then we could also do post_password = string to actually check the field's value. Thoughts?

[helen]

Seems like this could use an alternate approach, so punting.

[wonderboymusic]

20308.2.diff​ supports has_password => true|false|null and allows post_password to be passed explicitly, adding perm => 'readable' if perm is not already set.

Adds Unit Tests.

[F J Kaiser]

This one will knock out the arguments delivered in #16483

[nacin]

The latest patch looks good. I actually meant that has_password = null would be the default. So, isset() rather than array_key_exists().

I'm also making it so post_password overrules has_password if specified. No need for them to compete.

[nacin]

In 27395:

Add has_password and post_password query variables to WP_Query.

• has_password true means posts with passwords, false means posts without.
• post_password can query for posts with a particular password.

props wonderboymusic, robmiller.
fixes #20308.