Bulk export Drupal content in Markdown via Markdownify

export_md.php

<?php

/**
 * @file
 * Mass-exports Drupal nodes to Markdown files using the Markdownify module.
 *
 * DESCRIPTION:
 * This Drush script is designed for the mass-export of nodes into Markdown
 * (.md) files. It is optimized to handle a large number of nodes (10,000+)
 * efficiently by processing them in configurable chunks to prevent out-of-memory
 * issues.
 *
 * The script generates a clean, hierarchical directory structure for the
 * exported content based on their URL aliases. It also creates a comprehensive
 * 'export-overview.md' file that provides a summary of all exported items,
 * their status, and direct links to the generated files.
 *
 * USAGE:
 *   drush php-script export_md.php [<output-directory>]
 *
 * ARGUMENTS:
 *   <output-directory>  Optional. The path to the export directory. Can be
 *                       relative to the Drupal root or absolute.
 *                       Defaults to 'markdown_export' in the Drupal web root.
 *
 * EXAMPLES:
 *   # Export to the default 'web/markdown_export' directory
 *   drush php-script export_md.php
 *
 *   # Export to a custom absolute directory
 *   drush php-script export_md.php /path/to/my/exports
 */

use Drupal\node\Entity\Node;

// 1. Determine and prepare output directory.
$contentSubDir = 'content';
$outputDirArg = isset($extra[0]) ? $extra[0] : 'markdown_export';
if (substr($outputDirArg, 0, 1) !== '/') {
  $outputDir = DRUPAL_ROOT . '/' . $outputDirArg;
} else {
  $outputDir = $outputDirArg;
}

$contentDir = $outputDir . '/' . $contentSubDir;
if (!is_dir($contentDir)) {
  if (!mkdir($contentDir, 0755, TRUE)) {
    fwrite(STDERR, "Error: Failed to create content directory '$contentDir'\n");
    exit(1);
  }
}

print "Starting Markdown export...\n";
print "Output directory: $outputDir\n\n";

// 2. Fetch markdownify settings for configured view modes.
$config = \Drupal::config('markdownify.settings');
$supported_entities = $config->get('supported_entities') ?? [];

// 3. Query all nodes (both published and unpublished).
$query = \Drupal::entityTypeManager()->getStorage('node')
  ->getQuery()
  ->accessCheck(FALSE);
$nids = $query->execute();

if (empty($nids)) {
  print "No nodes found to export.\n";
  exit(0);
}

print "Found " . count($nids) . " nodes to export.\n";

$converter = \Drupal::service('markdownify.entity_converter');
$aliasManager = \Drupal::service('path_alias.manager');

$overviewRows = [];

// Define a safe chunk size for processing nodes to avoid memory issues.
define('NODE_CHUNK_SIZE', 50);

// Sort nodes by NID to make the overview consistent and processing predictable.
sort($nids, SORT_NUMERIC);

$nid_chunks = array_chunk($nids, NODE_CHUNK_SIZE);
$total_chunks = count($nid_chunks);

foreach ($nid_chunks as $chunk_index => $nid_chunk) {
  print "Processing chunk " . ($chunk_index + 1) . "/$total_chunks...\n";

  // Load all node objects for the current chunk in a single query.
  $nodes = Node::loadMultiple($nid_chunk);

  foreach ($nodes as $node) {
    $nid = $node->id();
    // Explicitly cast the label to a string to satisfy strict type checking.
    $title = (string) $node->label();
    $bundle = $node->bundle();
    $statusStr = $node->isPublished() ? 'Published' : 'Unpublished';
    $canonicalPath = '/node/' . $nid;

    // Get the human-readable label of the content type.
    $nodeType = \Drupal\node\Entity\NodeType::load($bundle);
    $bundleLabel = $nodeType ? (string) $nodeType->label() : $bundle;

    // Determine view mode based on Markdownify settings or fallback to 'full'.
    $view_mode = 'full';
    if (is_array($supported_entities) && isset($supported_entities['node']['view_modes'][$bundle])) {
      $view_mode = $supported_entities['node']['view_modes'][$bundle];
    }

    // Get the path alias if one exists.
    $alias = $aliasManager->getAliasByPath($canonicalPath);

    // Decide the relative export path of the file.
    $relativePath = '';
    if (!empty($alias) && $alias !== $canonicalPath && $alias !== '/') {
      // Trim leading/trailing slashes.
      $relativePath = trim($alias, '/');
    } else {
      $relativePath = 'node/' . $nid;
    }

    // Handle homepage or empty paths.
    if (empty($relativePath) || $relativePath === '/') {
      $relativePath = 'index';
    }

    // Append extension.
    $relativePath .= '.md';

    // Sanitize path slightly.
    $fullPath = $contentDir . '/' . $relativePath;
    $dir = dirname($fullPath);

    if (!is_dir($dir)) {
      mkdir($dir, 0755, TRUE);
    }

    try {
      print "[*] Exporting Node $nid ($title) -> $relativePath... ";

      // Generate Markdown using Markdownify.
      $markdown = $converter->convertEntityToMarkdown($node, $view_mode);

      // Write markdown file.
      if (file_put_contents($fullPath, $markdown) !== FALSE) {
        print "Success\n";
        $overviewRows[] = [
          'nid_link' => "[$nid]($canonicalPath)",
          'title' => str_replace(['|', "\n", "\r"], ['\|', ' ', ''], $title),
          'bundle_label' => $bundleLabel,
          'status' => $statusStr,
          'file_path' => $contentSubDir . '/' . $relativePath,
        ];
      } else {
        print "Failed to write file\n";
      }
    } catch (\Throwable $t) {
      print "Error (Skipped): " . $t->getMessage() . "\n";
    }
  }

  // Optional: Force garbage collection to free up memory after each chunk.
  if (function_exists('gc_collect_cycles')) {
    gc_collect_cycles();
  }
}

// 4. Generate the Overview Markdown Table.
$overviewFile = $outputDir . '/export-overview.md';
$overviewContent = "# Export Overview\n\n";
$overviewContent .= "Generated on: " . date('Y-m-d H:i:s') . "\n\n";
$overviewContent .= "| Node (ID) | Title | Content Type | Status | File Path |\n";
$overviewContent .= "| --- | --- | --- | --- | --- |\n";

foreach ($overviewRows as $row) {
  $overviewContent .= "| {$row['nid_link']} | {$row['title']} | {$row['bundle_label']} | {$row['status']} | [`{$row['file_path']}`]({$row['file_path']}) |\n";
}

if (file_put_contents($overviewFile, $overviewContent) !== FALSE) {
  print "\n[+] Created overview table: $overviewFile\n";
} else {
  print "\n[-] Failed to create overview table: $overviewFile\n";
}

print "Export process complete!\n";