Override Ninja Forms Submission download link to download all the things without writing to filesystem

ninja-forms-export-all-the-things.php

<?php
namespace MY_R_KEY_DOESNT_WORRRRK_PROPERLY;

/**
 * Download all submissions of a form, between a specific range if provided.
 *
 * @action wp_ajax_ninja_forms_export_all_subs
 */
function download_all_subs() {
	$form_id = filter_input( INPUT_GET, 'form_id', FILTER_SANITIZE_NUMBER_INT );
	$from    = filter_input( INPUT_GET, 'from' );
	$to      = filter_input( INPUT_GET, 'to' );

	if ( empty( $form_id ) ) {
		wp_die( esc_html__( 'Invalid form ID passed', 'hello-dolly' ) );
	}

	$args = [
		'posts_per_page' => -1,
		'post_type'      => 'nf_sub',
		'fields'         => 'ids',
		'meta_query'     => [
			[
				'key'   => '_form_id',
				'value' => $form_id,
			],
		],
		'no_found_posts' => true,
	];

	if ( $from && $to ) {
		$args['date_query'] = [
			'after'     => date( 'r', $from ),
			'before'    => date( 'r', $to ),
			'inclusive' => true,
		];
	}

	$post_ids = get_posts( $args );

	if ( empty( $post_ids ) ) {
		wp_die( esc_html__( 'No submissions found in the chosen date range.', 'byebye-dolly' ) );
	}

	\NF_Database_Models_Submission::export( $form_id, $post_ids );
}

add_action( 'wp_ajax_ninja_forms_export_all_subs', __NAMESPACE__ . '\\download_all_subs' );

/**
 * Alter the URL of the submissions download link to point to our new endpoint
 *
 * @filter ninja_forms_download_submissions_url
 *
 * @return string
 */
function download_all_subs_url_change( $url, $form_id ) {
	$args = [
		'form_id' => absint( $form_id ),
		'from'    => get_date_from_gmt( date( 'Y-m-d H:i:s', strtotime( filter_input( INPUT_GET, 'begin_date' ) ) ), 'U' ),
		'to'      => get_date_from_gmt( date( 'Y-m-d H:i:s', strtotime( filter_input( INPUT_GET, 'end_date' ) ) ), 'U' ),
	];

	$url = add_query_arg( array_filter( $args ), admin_url( 'admin-ajax.php?action=ninja_forms_export_all_subs' ) );

	return $url;
}

// See https://github.com/wpninjas/ninja-forms/pull/3259
add_filter( 'ninja_forms_download_all_submissions_url', __NAMESPACE__ . '\\download_all_subs_url_change', 10, 2 );