How to filter content for specific content variable

Question

I created a plugin that adds content from another post, and places this content next to the original content. I can say, that this content should appear at the bottom of the original post content.

I get post_content for my additional post, and then call apply_filter('the_content', $custom) but this code does this not only for my $custom, but for original content as well! What am I doing wrong?

add_filter( 'the_content', 'custom_content' );

function custom_content( $content ) {

    $customPost = get_post( 22 );
    remove_filter( 'the_content', 'custom_content' );
    $html = $customPost->post_content;
    $html = apply_filters( 'the_content', $html );

    return $content . $html;

}

Answer 1

the_content will return the whole content of the post and not particular part. If you want to access your particular part, then you can go for shortcode.

For eg, if you have content like this in your post

Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's [mycustomtextpart] standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has

Then use do_shortcode function to make changes in the [mycustomtextpart] section. Refer.