Providing a function to override the default query

Question

In a plugin, I want to provide a function for users to set the default query in their templates, so they can use some custom loops. What would be the best way of doing it?

I imagine something like this:

my_plugin_set_query();
if ( have_posts() ) {
    while ( have_posts() ) {
        the_post();
        ... iteration through a predefined post set ...
    }
}

Answer 1

If you want to plug into the query, pre_get_posts() is going to be your friend. Pippin Williamson also has a great writeup on the subject.

Answer 2

I did this, and it's working, but I'm not sure if it's the best way of doing it:

function get_override_query() {
    $posts = get_posts_from_some_custom_method();
    $query = new WP_Query();
    $query->current_post = -1;
    $query->post_count = count( $posts );
    $query->posts = $posts;        
    return $query;
}

function override_query() {
    global $wp_query;
    $query = get_override_query();
    $wp_query = $query;
}

Then, I can also iterate through posts without changing the default query, like:

$query = get_override_query();
while ( $query->has_posts() ) {
    $query->the_post();
    ...
}