PHP Wallhaven.cc full-resolution wallpaper downloader by keyword search

wallhaven_downloader.php

<?php
//// Simple Wallhaven downloader
// Downloads wallpapers from Wallhaven.cc at full resolution by searching for specified keywords

$keywords = [
  'waterfall',
  'nature',
  'mountains',
];

// Resolutions (finds wallpapers of exactly these resolutions)
// Separate by comma for multiple
// eg. $resolutions = '1920x1080,2560x1440'
$resolutions = '';

// Minimum resolution (finds wallpapers of atleast this resolution)
// eg. $atleast = '1280x720'
$atleast = '';

// Use either $resolutions or $atleast and leave the other one blank

// Aspect ratios
// Valid values: [ 4x3, 5x4, 16x9, 16x10, 21x9, 32x9, 48x9, 9x16, 10x16, ]
// Separate by comma for multiple
$aspect_ratio = '16x9';

// Sort order
// Valid values: [ relevance, random, date_added, views, favorites, toplist ]
$sorting = 'relevance';

// Colors
// Any 3-byte hex value, searches by dominant color
$colors = '';

// Categories
// Field order [ General, Anime, People ]
// eg. General = 100, Anime & People = 011
$categories = '100';

// Purity
// Field order [ SFW, Sketchy, ? ]
// eg. SFW = 100, SFW & Sketchy = 110
$categories = '100';

///////////////////////////////////////////////////////////////////////////////
foreach ($keywords as $keyword) {
  $url = "https://alpha.wallhaven.cc/search?q={$keyword}";
  $url .= "&sorting=relevance";
  $url .= "&order=desc";

  if (!empty($categories))   $url .= "&categories={$categories}";
  if (!empty($purity))       $url .= "&purity={$purity}";
  if (!empty($resolutions))  $url .= '&resolutions='.urlencode($resolutions);
  else if (!empty($atleast)) $url .= "&resolutions={$atleast}";
  if (!empty($aspect_ratio)) $url .= "&ratios={$aspect_ratio}";
  if (!empty($colors))       $url .= "&colors={$colors}";

  echo $url."\n";

  $ch = curl_init($url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HEADER, 0);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  $html = curl_exec($ch);

  $re = '/data-wallpaper-id="(\d+)"/';
  preg_match_all($re, $html, $matches);

  echo "Found ".count($matches[1])." wallpapers ..\n";
  foreach ($matches[1] as $match) {
    $id = $match;
    $filename = "wallhaven-{$id}.jpg";

    if (!file_exists($filename)) {
      $img_url = "https://alpha.wallhaven.cc/wallpapers/full/{$filename}";
      $data = file_get_contents($img_url);
      if (strlen($data) <= 1) continue;

      file_put_contents($filename, $data);
      echo "Downloaded {$filename}\n";
    }
  }
}