Filtering bp_ajax_querystring

bp-custom.php

<?php
/**
 * Filter the querystring when on the activity directory
 *
 * @param  string/array $query_string component loop arguments
 * @param  sting $object       component name
 * @return string the edited query string
 */
function bphelp_ajax_querystring( $query_string, $object ) {

	// if not a query string about activities, return without modifying
	if ( 'activity' != $object ) {
		return $query_string;
	}

	// if not on the activity directory page, return without modifying
	if ( ! bp_is_activity_directory() ) {
		return $query_string;
	}

	// Make sure we will manipulate an array
	$query_args = wp_parse_args( $query_string, array() );

	/**
	 * About overriding scope
	 * the commented line would force the scope to be just-me but on the activity
	 * directory there's the mentions/friends tab so it would prevent mentions to
	 * ever appear for instance
	 */
	//$query_args['scope'] = 'just-me';

	/**
	 * A nicer way to deal with it...
	 * (add as much scopes as needed)
	 */
	$enabled_scopes = array( 'mentions', 'friends', 'just-me' );

	if ( ! empty( $query_args['scope'] ) ) {
		$scopes = explode( ',', $query_args['scope'] );
		$scopes_to_use = array_intersect( $scopes, $enabled_scopes );

	// Default to just-me
	} else {
		$scopes_to_use = array( 'just-me' );
	}

	$query_args['scope'] = join( ',', $scopes_to_use );

	// random example..
	$query_args['per_page'] = 1;

	// Build the querystring
	$new_query_string = http_build_query( $query_args );

	// it's always a good idea to allow other edit the querystring
	// and to include the originale querystring
	return apply_filters( 'bphelp_ajax_querystring', $new_query_string, $query_string );

}
add_filter( 'bp_ajax_querystring', 'bphelp_ajax_querystring', 20, 2 );