get total number of images from media using xml-rpc

I have large number of images in media library so I am accessing images in chunks via pagination in my Ruby on Rails application. I pass page number and offset to wp.getMediaLibrary API and it returns fixed number of images. So counting returned images is useless.

Here is my approach to get total number of images.

If we call wp.getMediaLibrary without passing number and offset, it will return all images and we can get count of images from results.

But the problem with this approach is that the site has huge number of images and so something goes wrong at server end and API return empty response.

Can anybody please guide me how to get count of images without getting all images information?

VERSION 1 will query all the images and give you a count by checking the size of the returned array. VERSION 2 is a much faster method introduced by birgire.

// VERSION 1

    $images = get_posts(array(
        'post_type'         => 'attachment',
        'post_status'       => 'any',
        'numberposts'       => -1,
        'fields'            => 'ids',
        'post_mime_type'    => 'image/jpeg,image/gif,image/jpg,image/png',
    ));

    echo count($images) . ' images total';

// VERSION 2

    $count = array_sum( (array) wp_count_attachments( 'image' ) );

    echo "{$count} images total";

ORIGINAL – For a full XML-RPC solution, create a custom method.

function xml_add_method( $methods ) {
    $methods['myNamespace.attachmentCount'] = 'get_attachment_count';
    return $methods;
}
add_filter( 'xmlrpc_methods', 'xml_add_method' );

function get_attachment_count( $args ) {
    // good to know it's here
    // global $wpdb; 

    // params passed in the call - not needed in this example
    $params = $args[3];

    // count the posts then return the total value
    $images = get_posts(array(
        'post_type'         => 'attachment',
        'post_status'       => 'any',
        'numberposts'       => -1,
        'fields'            => 'ids',
        'post_mime_type'    => 'image/jpeg,image/gif,image/jpg,image/png',
    ));

    // images total
    return count($images); 
}

Then do the RPC

global $current_user;

$user = $current_user->user_login;
$password = $user->data->user_pass;

include_once( ABSPATH . WPINC . '/class-IXR.php' );
include_once( ABSPATH . WPINC . '/class-wp-http-ixr-client.php' );
$xmlrpc_url = home_url('xmlrpc.php');
$client = new WP_HTTP_IXR_CLIENT( $xmlrpc_url );

// set this to true if you need help
// $client->debug = true;

$response = $client->query( 'myNamespace.attachmentCount', array(
    0,
    $user,
    $password,
    array(
        'post_type'         => 'attachment',
        'post_status'       => 'any',
    )
) );

if ( is_wp_error( $response ) ) {
    $error_message = $response->get_error_message();
    echo "Something went wrong: $error_message";
} else {
    echo 'Response:<pre>';        
    $count = $client->message->params[0]; // our return value is here
    print_r( $count . ' images total' );
    echo '</pre>';
}

UPDATE
Merging @birgire’s solution into this one.

add_filter('xmlrpc_methods', function ($methods) {
    $methods['myNamespace.getTotalImageCount'] = 'rpc_myNamespace_getTotalImageCount';
    return $methods;
});

function rpc_myNamespace_getTotalImageCount($args)
{
    return array_sum((array)wp_count_attachments('image'));
}

add_action('parse_request', function () {

    // PULL USER CREDS FROM CURRENT USER
    global $current_user;

    $user = $current_user->user_login;
    $password = $user->data->user_pass;

    include_once(ABSPATH . WPINC . '/class-IXR.php');
    include_once(ABSPATH . WPINC . '/class-wp-http-ixr-client.php');
    $xmlrpc_url = home_url('xmlrpc.php');
    $client = new WP_HTTP_IXR_CLIENT($xmlrpc_url);

    // CALL OUR CUSTOM METHOD
    $response = $client->query('myNamespace.getTotalImageCount', array(0, $user, $password));

    echo 'Response:<pre>';
    $count = $client->message->params[0];
    print_r("{$count} total images");
    echo '</pre>';

    wp_die('FIN');
});