Buddypress allow site admins to join any group


//
// creates a new join button to allow the site admin to join any group
//

function scg_site_admin_group_join_button() {
        global $bp, $groups_template;

        $group =& $groups_template->group;

        if ( !$bp->loggedin_user->is_site_admin )
                return false;

        if ( !$group->is_member && $group->status != 'public' )
                echo '<div class="generic-button">Site Admin can <a class="join-group" href="' . wp_nonce_url( bp_get_group_permalink( $group ) . 'admin-join', 'admin_groups_join_group' ) . '">' . __( 'Join Group', 'buddypress' ) . '</a></div>';

}
add_action( 'bp_group_header_meta', 'scg_site_admin_group_join_button', 1);

// catch the join request from the button added in function above
function scg_admin_groups_action_join_group() {
        global $bp;

        if ( !$bp->loggedin_user->is_site_admin || !$bp->is_single_item || $bp->current_component != $bp->groups->slug || $bp->current_action != 'admin-join' )
                return false;

        // Nonce check
        if ( !check_admin_referer( 'admin_groups_join_group' ) )
                return false;

        // User wants to join any group
        if ( !groups_join_group( $bp->groups->current_group->id ) )
                bp_core_add_message( __( 'There was an error joining the group.', 'buddypress' ), 'error' );
        else
                bp_core_add_message( __( 'You joined the group!', 'buddypress' ) );

        bp_core_redirect( bp_get_group_permalink( $bp->groups->current_group ) );
}
add_action( 'wp', 'scg_admin_groups_action_join_group', 3 );