Enable pagination for the XML-RPC getRecentPosts function

[feedfabrik]

To retrieve posts via the XML-RPC API, currently the following methods can be called:

• blogger.getRecentPosts
• metaWeblog.getRecentPosts
• mt.getRecentPostTitles

In changeset r16256 these methods were enhanced to support an optional number of posts. However, the query still always starts from the most recent post and there is no way to retrieve older posts without increasing the optional number of posts to a sufficiently large number and retrieving everything before as well. This can place an unnecessary and unwanted burden on the server.

There is an alternative of requesting a post by ID but for this the ID needs to be known in advance. Until ticket #6850 is addressed, there is no way to query for specific IDs.

I would like to suggest an enhancement that leverages r16256 and introduces another optional parameter for offset.

As an example, the code for blogger_getRecentPosts would get an additional:

if ( isset( $args[5] ) )
    $query['offset'] = absint( $args[5] );

That should be enough to get wp_get_recent_posts from post.php do the job.

On more general terms, a new XML-RPC method wp.getPosts could be introduced that simply accepts the array used in wp_get_recent_posts for even more flexibility, but that's probably stuff for another ticket.

[redsweater]

This has been a major performance/usability challenge for all clients, for years. I've been hoping it would get changed and never thought to propose something as simple as this. It would certainly be a welcome addition.

[redsweater]

One other thought: can you do something to expose the feature to clients, i.e. through the wlwmanifest file, or something? We need to know whether we can request an offset-relative get with confidence.

[feedfabrik]

Any hope of a review here? Is there anything I can do to make this process work? Contribute code in a different form?

I have also started a discussion on ​http://wordpress.stackexchange.com/questions/7303/how-to-get-all-posts-in-chunks-via-xml-rpc

[ericmann]

Replying to feedfabrik:

Is there anything I can do to make this process work? Contribute code in a different form?

If you could contribute a patch, or at least the start of a patch, it would move a lot faster. I had planned to contribute a patch for this already, I just haven't had the time to focus on it.

But if you patch it, it will eventually get reviewed and probably committed to core.

[feedfabrik]

Well, it is only the two lines I've already submitted in my ticket 7 months ago. What else do you need as a patch?

[feedfabrik]

Suggested patch for function mw_getRecentPosts in class-wp-xmlrpc-server.php based on trunk

[maxcutler]

Extended feedfabrik's patch to include all 3 relevant XML-RPC methods

[maxcutler]

I've added feedfabrik's changes to the other two mentions mentioned in the original description. nacin pointed out on IRC that technically these API specs don't support an offset parameter, so we'd be breaking those contracts.

Given that the mw.* method implementations already take liberties with the spec by adding WP-specific content_struct fields, I don't have a problem extending it in this way.

The alternative is to wait for #18433 to be polished and committed in 3.4 or later.

[feedfabrik]

Thanks, maxcutler. As far as I understand, you're not really breaking the contract by adding to the API. The modified API is a superset of the existing API, so this should be totally transparent.

[westi]

I don't think we should be adding an offset to these older APIs I think it is better to encourage clients to switch to the newer WP namespaced api we are working on in #18433 if they want to go further back into the archives.

[markoheijnen]

Can be closed since it can be done with the wp.getPosts #18433