ACF Gallery field images donwload

Question

I have the following image gallery in ACF:

$slider = get_field( 'slider' );

I need to create a function so that with a single click, the entire image gallery is turned over to a .zip file. Anyone have something similar? I've found some things, but for some reason it doesn't work. Thanks.

EDIT:

I have tried to implement this:

<?php 
if ( $slider ) :
    $destination = 'downloads/' . sanitize_title( get_the_title() ) . '.zip';
    if ( file_exists( $destination ) ) {
        echo '<a href="' . esc_url( home_url( '/' ) ) . $destination . '" class="download-link" download>DOWNLOAD ALL</a>';
    } else {
        $files = array();
        foreach ( $slider as $singlefile ) {
            $files[] = get_attached_file( $singlefile['ID'] );
        }

        if ( count( $files ) ) {
            $zip = new ZipArchive();
            $zip->open( $destination, ZipArchive::CREATE );

            foreach ( $files as $file ) {

                if ( file_exists( $file ) ) {
                    $new_filename = substr( $file, strrpos( $file, '/' ) + 1 );
                    $zip->addFile( $file, $new_filename );
                }
            }
            $zip->close();

            echo '<a href="' . esc_url( home_url( '/' ) ) . $destination . '" class="download-link" download>DOWNLOAD ALL</a>';
        } else {
            echo 'no files found';
        }
    }
endif;
?>

But when the file is downloaded, I receive a download error and I don't know what I am doing wrong.

Answer 1

I'm using this same code and I was able to figure out where the error's happening. The path that gets generated when this line of code is called is wrong:

$zip->open( $destination, ZipArchive::CREATE );

It spits out your home directory and then appends the value of $destination to it.

In my case (it's not the cleanest solution, but it's the one I ended up doing), I hard-coded the destination instead of using the variable.

$zip->open( 'wp-content/themes/my theme/downloads/' . sanitize_title( get_the_title() ) . '.zip', ZipArchive::CREATE );