Customize Search to only search current custom post type

Question

I have 3 custom post types and want the search widget to only search the custom post type it's currently on. ie. If viewing cpt_1 (single or archive) and someone uses the search widget in the sidebar it should only return results of cpt_1. Similarly viewing cpt_2 and searching should only return cpt_2 results.

I tried this:

<?php
// functions.php 
function search_cpt1( $query ) {
    if ( $query->is_search ) {
        $query->set( 'post_type', array( 'cpt1' ) );
    }
    return $query;
}   

function search_cpt2( $query ) {
    if ( $query->is_search ) {
        $query->set( 'post_type', array( 'cpt2' ) );
    }
    return $query;
}   

if ( 'cpt1' == get_post_type() ) {
    add_filter( 'pre_get_posts', 'search_cpt1' );
}

if ( 'cpt2' == get_post_type() ) {
    add_filter( 'pre_get_posts', 'search_cpt2' );
}

?>

I've also tried this way without success:

<?php
function jc_search_cpts( $query ) {
    if (('cpt1' == get_post_type()) && ( $query->is_search )) {
            $query->set( 'post_type', array( 'cpt1' ));
    }
    if (('cpt2' == get_post_type()) && ( $query->is_search )) {
            $query->set( 'post_type', array( 'cpt2' ));
    }
    return $query;
}
add_filter( 'pre_get_posts', 'jc_search_cpts' );

Answer 1

You will need to modify searchform.php file in your theme directory.

To search for current post type posts add following code inside the form !

$post_type = get_post_type();
if($post_type){
    echo '<input type="hidden" name="post_type" value="'.$post_type.'" />';
}

Answer 2

You can also do it using a WordPress filter pre_get_posts. Add or remove the post types as you see fit.

function es_search_filter($query)
{

    if ($query->is_search && !is_admin()) {
        $query->set('post_type', ['pages', 'posts']);
    }

    return $query;
}

add_filter('pre_get_posts', 'es_search_filter');

Answer 3

I was able to do this by creating a custom search form by adding this:

<input type="hidden" name="post_type" value="attorney" />

So, my search form looks like this:

<form role="search" method="get" id="searchform" action="<?php echo home_url( '/' ); ?>">
<input type="hidden" name="post_type" value="attorney" />
<input type="text" value="" name="s" />
<input type="submit" value="Search" />
</form>