Display all post types together

Question

I'm looking to use Custom Post Types to create a simplified process for key individuals to add information to a webpage. Let's use a Job Posting as an example, with custom fields for Job Title, Closing Date, etc.

However, I also have regular posts across a number of categories.

I would like to have all posts listed together. So for the home page where it shows the last 3 posts, that includes those in custom post types (there will be several).

I would also like to have these custom posts automatically set to specific categories, but these categories should be a part of the regular post types. If "Job Postings" and "Press Releases" are two categories under my regular post menu, I would also like a CPT of "Job_Posting" to be set to "Job Postings" automatically.

This is for situations where we need to post information that would belong to a job posting category but wouldn't necessarily be an actual postings with the required fields set up in that CPT.

Am I going about this the wrong way entirely?

---

Update:

I've changed my WP_Query to the following, and it still won't show CPT:

<ul class="home-content-recent">
            <?php 
            $args = array(
                'post_type' => 'any',
            );
            $recent = new WP_Query($args);
            $recent->query('showposts=3');
            if($recent->have_posts()) : while($recent->have_posts()): $recent->the_post();?>
        <li>
        <a class="recent-title" href="<?php the_permalink()?>"><?php the_title()?></a>
        <div class="post-meta-data">
        <p class="recent-time"><?php the_time('l, F j, Y')?></p>
        <p class="recent-category"><?php the_category(', '); ?></p>
        <p class="recent-commentcount"><?php comments_number( 'No Comments', '1 Comment', '% Comments' ); ?></p>
        </div>
        <div class="recent-excerpt"><?php the_excerpt()?></div>
        </li>
            <?php endwhile ?>
            <?php else : ?>
            <?php endif ?>
</ul>

Answer 1

For the first part of your question, a pre_get_posts hook is all you would need. This code should work, providing you are using the default "Latest Posts" setting as your front page (Settings > Reading).

add_action( 'pre_get_posts', 'se132019_home_page_all_post_types' );
function se132019_home_page_all_post_types( $query ) {
    if ( ! is_admin() $query->is_main_query() && $query->is_posts_page() ) {
        $query->set( 'post_type', 'any' );
    }
}

If you are using a custom WP_Query, just add 'post_type' => 'any' as an argument.

The second piece is a personal preference for you - you could just house all posts in Posts, and display them differently depending on the terms (categories) they are attached to. Otherwise, you would need to do the following 2 things:

1. Add your custom post types (Job Listings) to the category taxonomy. This can be done when registering the post type using taxonomies argument, or using register_taxonomy_for_object_type.
2. hook into the save_post method, check to see if the post was attached to any Categories. If not, manually assign it to the proper category, depending on which post type it was.

EDIT::

your first couple lines should look like the following. When a WP_Query object is created, it automatically calls the query() function. You are calling it a second time, passing it new arguments.

        <?php 
        $args = array(
            'post_type' => 'any',
            'posts_per_page' => 3
        );
        $recent = new WP_Query($args);