wplf-export.php

<?php
/**
 * Plugin name: WPLF Export
 * Plugin URI: https://github.com/k1sul1/wplf-export
 * Description: Export form data from WP Libre Form
 * Version: 1.0.1
 * Author: @k1sul1
 * Author URI: https://github.com/k1sul1
 * License: GPLv3
 * License URI: https://www.gnu.org/licenses/gpl.html
 * Text Domain: wplf-export
 */

/** Copyright 2017 Christian Nikkanen
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 3, as
  published by the Free Software Foundation.
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  GNU General Public License for more details.
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

class WPLF_Export {
  public static $instance;

  public static function instance() {
    if (is_null(self::$instance)) {
      self::$instance = new WPLF_Export();
    }

    return self::$instance;
  }

  public function __construct() {
    add_filter('bulk_actions-edit-wplf-submission', array($this, 'bulkAction'));
    add_filter('handle_bulk_actions-edit-wplf-submission', array($this, 'handleBulk'), 10, 3);
    add_action('template_redirect', array($this, 'handleDownload'));
    add_action('admin_notices', array($this, 'noticeNag'));
  }

  public function bulkAction($options) {
    $options['wplf_export'] = __('Export', 'wplf-export');

    return $options;
  }

  public function handleBulk($redirect_to, $action, $post_ids) {
    if ($action !== 'wplf_export') {
      return $redirect_to;
    }

    // Export form id.
    $efid = !empty($_GET['form']) ? (int) $_GET['form'] : NULL;

    $filter_fn = function($field_name) {
      return $field_name[0] !== '_';
    };

    if (has_action("wplf_export_form_{$efid}_filter")) {
      $filter = apply_filters("wplf_export_form_{$efid}_filter", $filter_fn);
    } else {
      $filter = apply_filters('wplf_export_form_filter', $filter_fn);
    }

    $header = array();
    $rows = array();
    $errors = array();
    $queryvars = array();

    for ($i = 0; $i < count($post_ids); $i++) {
      // Should handle uploaded files fine.
      $id = $post_ids[$i];
      $meta = get_post_meta($id);
      $fields = array_filter(array_keys($meta), $filter);

      if ($i === 0) {
        $header = $fields;
      }

      $row = array();
      foreach ($fields as $field) {
        $row[] = $meta[$field][0];
      }

      if (count($row) !== count($header)) {
        $queryvars['wplf_export_error'] = 'ERR_HEADER_ROW_MISMATCH';
        $errors[] = array($id => 'ERR_HEADER_ROW_MISMATCH');
      }

      $rows[] = $row;
    }

    if (count($errors) > 0) {
      error_log(print_r($errors, true));
    }

    if (has_action("wplf_export_form_{$efid}_delimiter")) {
      $delimiter = apply_filters("wplf_export_form_{$efid}_delimiter", ',');
    } else {
      $delimiter = apply_filters('wplf_export_form_delimiter', ',');
    }

    $filename = 'wplf_export_' . date('U') . '.csv';
    if (has_action("wplf_export_form_{$efid}_filename")) {
      $filename = apply_filters("wplf_export_form_{$efid}_filename", $filename);
    } else {
      $filename = apply_filters('wplf_export_form_filename', $filename);
    }

    $csvpath = $this->generateCSV($filename, $header, $rows, $delimiter);
    $queryvars['wplf_export_path'] = $csvpath;
    $queryvars['wplf_exported_posts'] = count($post_ids);

    $redirect_to = add_query_arg($queryvars, $redirect_to);
    return $redirect_to;
  }

  public function generateCSV($filename = 'wplf_export.csv', $header = array(), $rows = array(), $delimiter = ',') {
    $uploads = wp_upload_dir('wplf'); // meant for date, but works with a string too
    $path = $uploads['basedir'] . DIRECTORY_SEPARATOR . 'wplf' . DIRECTORY_SEPARATOR . $filename;
    $handle = fopen($path, 'w+');

    fputcsv($handle, $header, $delimiter);

    foreach ($rows as $row) {
      fputcsv($handle, $row, $delimiter);
    }

    return $path;
  }

  public function getCSV($filepath) {
    $path = $filepath;

    if (!file_exists($path)) {
      return false;
    }

    $handle = fopen($path, 'r');
    $csv = '';

    while(!feof($handle)) {
      $csv .= fread($handle, 8192);
    }

    fclose($handle);

    return $csv;
  }

  public function handleDownload() {
    if (parse_url($_SERVER["REQUEST_URI"], PHP_URL_PATH) === '/wplf-export') {
      $allowed = current_user_can(
          apply_filters('wplf_export_capability', 'edit_others_posts')
      );
      $uploads = wp_upload_dir();
      $filename = basename($_REQUEST['wplf-export-download']);

      // Do not trust the parameter! Only allow files from this folder.
      $filepath = $uploads['basedir'] . DIRECTORY_SEPARATOR . 'wplf' . DIRECTORY_SEPARATOR . $filename;

      if ($allowed && $filepath) {
        $data = $this->getCSV($filepath);


        if ($data) {
          header("Content-Type: application/csv", true, 200);
          header("Content-Disposition: attachment; filename=$filename");
          echo $data;

          // Remove the file after download
          ignore_user_abort(true);
          register_shutdown_function('unlink', $filepath); // Never pass unsanitized filepath!
          die();
        }
      }
    }
  }

  public function noticeNag() {
    $r = $_REQUEST;

    $html = "";
    $fpath = !empty($_REQUEST['wplf_export_path']) ? urlencode($_REQUEST['wplf_export_path']) : null;

    if (!empty($r['wplf_export_error'])
        && $r['wplf_export_error'] === 'ERR_HEADER_ROW_MISMATCH') {
      $html .= "<div id='wplf_export_nag' class='notice notice-error is-dismissible'>";
      $html .= "<p>Row item count was different from header item count.
        This is usually caused by selecting multiple different forms for
        one export, or modifying the form fields after it has submissions.</p>
        <p>If the imported file seems to be broken, select only one type
        of form and try exporting again.</p>";
      $html .= "<p>The download should start automatically.
        <a href='/wplf-export?wplf-export-download=$fpath' id='wplf_export_save' target='_blank'>
        If it doesn't click here.
        </a></p>";
      $html .= "</div>";
    } else if (!empty($r['wplf_exported_posts'])) {
      $count = (int) $r['wplf_exported_posts'];

      $html .= "<div id='wplf_export_nag' class='notice notice-success is-dismissible'>";
      $html .= "<p>Exported $count submissions.</p>";
      $html .= "<p>The download should start automatically.
        <a href='/wplf-export?wplf-export-download=$fpath' id='wplf_export_save' target='_blank'>
        If it doesn't click here.
        </a></p>";
      $html .= "</div>";

      $html .= "<script>setTimeout(function(){document.getElementById('wplf_export_save').click();},100);</script>";
    }

    echo $html;
  }
}

WPLF_Export::instance();