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<?php
/**
* @package dompdf
* @link https://github.com/dompdf/dompdf
* @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
*/
namespace Dompdf\Image;
use Dompdf\Options;
use Dompdf\Helpers;
use Dompdf\Exception\ImageException;
/**
* Static class that resolves image urls and downloads and caches
* remote images if required.
*
* @package dompdf
*/
class Cache
{
/**
* Array of downloaded images. Cached so that identical images are
* not needlessly downloaded.
*
* @var array
*/
protected static $_cache = [];
/**
* @var array
*/
protected static $tempImages = [];
/**
* Array of image references from an SVG document.
* Used to detect circular references across SVG documents.
*
* @var array
*/
protected static $svgRefs = [];
/**
* The url to the "broken image" used when images can't be loaded
*
* @var string
*/
public static $broken_image = "data:image/svg+xml;charset=utf8,%3C?xml version='1.0'?%3E%3Csvg width='64' height='64' xmlns='http://www.w3.org/2000/svg'%3E%3Cg%3E%3Crect stroke='%23666666' id='svg_1' height='60.499994' width='60.166667' y='1.666669' x='1.999998' stroke-width='1.5' fill='none'/%3E%3Cline stroke-linecap='null' stroke-linejoin='null' id='svg_3' y2='59.333253' x2='59.749916' y1='4.333415' x1='4.250079' stroke-width='1.5' stroke='%23999999' fill='none'/%3E%3Cline stroke-linecap='null' stroke-linejoin='null' id='svg_4' y2='59.999665' x2='4.062838' y1='3.750342' x1='60.062164' stroke-width='1.5' stroke='%23999999' fill='none'/%3E%3C/g%3E%3C/svg%3E";
public static $error_message = "Image not found or type unknown";
/**
* Resolve and fetch an image for use.
*
* @param string $url The url of the image
* @param string $protocol Default protocol if none specified in $url
* @param string $host Default host if none specified in $url
* @param string $base_path Default path if none specified in $url
* @param Options $options An instance of Dompdf\Options
*
* @return array An array with three elements: The local path to the image, the image
* extension, and an error message if the image could not be cached
*/
static function resolve_url($url, $protocol, $host, $base_path, Options $options)
{
$tempfile = null;
$resolved_url = null;
$type = null;
$message = null;
try {
$full_url = Helpers::build_url($protocol, $host, $base_path, $url);
if ($full_url === null) {
throw new ImageException("Unable to parse image URL $url.", E_WARNING);
}
$parsed_url = Helpers::explode_url($full_url);
$protocol = strtolower($parsed_url["protocol"]);
$is_data_uri = strpos($protocol, "data:") === 0;
if (!$is_data_uri) {
$allowed_protocols = $options->getAllowedProtocols();
if (!array_key_exists($protocol, $allowed_protocols)) {
throw new ImageException("Permission denied on $url. The communication protocol is not supported.", E_WARNING);
}
foreach ($allowed_protocols[$protocol]["rules"] as $rule) {
[$result, $message] = $rule($full_url);
if (!$result) {
throw new ImageException("Error loading $url: $message", E_WARNING);
}
}
}
if ($protocol === "file://") {
$resolved_url = $full_url;
} elseif (isset(self::$_cache[$full_url])) {
$resolved_url = self::$_cache[$full_url];
} else {
$tmp_dir = $options->getTempDir();
if (($resolved_url = @tempnam($tmp_dir, "ca_dompdf_img_")) === false) {
throw new ImageException("Unable to create temporary image in " . $tmp_dir, E_WARNING);
}
$tempfile = $resolved_url;
$image = null;
if ($is_data_uri) {
if (($parsed_data_uri = Helpers::parse_data_uri($url)) !== false) {
$image = $parsed_data_uri["data"];
}
} else {
list($image, $http_response_header) = Helpers::getFileContent($full_url, $options->getHttpContext());
}
// Image not found or invalid
if ($image === null) {
$msg = ($is_data_uri ? "Data-URI could not be parsed" : "Image not found");
throw new ImageException($msg, E_WARNING);
}
if (@file_put_contents($resolved_url, $image) === false) {
throw new ImageException("Unable to create temporary image in " . $tmp_dir, E_WARNING);
}
self::$_cache[$full_url] = $resolved_url;
}
// Check if the local file is readable
if (!is_readable($resolved_url) || !filesize($resolved_url)) {
throw new ImageException("Image not readable or empty", E_WARNING);
}
list($width, $height, $type) = Helpers::dompdf_getimagesize($resolved_url, $options->getHttpContext());
if (($width && $height && in_array($type, ["gif", "png", "jpeg", "bmp", "svg","webp"], true)) === false) {
throw new ImageException("Image type unknown", E_WARNING);
}
if ($type === "svg") {
$parser = xml_parser_create("utf-8");
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, false);
xml_set_element_handler(
$parser,
function ($parser, $name, $attributes) use ($options, $parsed_url, $full_url) {
if (strtolower($name) === "image") {
if (!\array_key_exists($full_url, self::$svgRefs)) {
self::$svgRefs[$full_url] = [];
}
$attributes = array_change_key_case($attributes, CASE_LOWER);
$urls = [];
$urls[] = $attributes["xlink:href"] ?? "";
$urls[] = $attributes["href"] ?? "";
foreach ($urls as $url) {
if (empty($url)) {
continue;
}
$inner_full_url = Helpers::build_url($parsed_url["protocol"], $parsed_url["host"], $parsed_url["path"], $url);
if (empty($inner_full_url)) {
continue;
}
self::detectCircularRef($full_url, $inner_full_url);
self::$svgRefs[$full_url][] = $inner_full_url;
[$resolved_url, $type, $message] = self::resolve_url($url, $parsed_url["protocol"], $parsed_url["host"], $parsed_url["path"], $options);
if (!empty($message)) {
throw new ImageException("This SVG document references a restricted resource. $message", E_WARNING);
}
}
}
},
false
);
if (($fp = fopen($resolved_url, "r")) !== false) {
while ($line = fread($fp, 8192)) {
xml_parse($parser, $line, false);
}
fclose($fp);
xml_parse($parser, "", true);
}
xml_parser_free($parser);
}
} catch (ImageException $e) {
if ($tempfile) {
unlink($tempfile);
}
$resolved_url = self::$broken_image;
list($width, $height, $type) = Helpers::dompdf_getimagesize($resolved_url, $options->getHttpContext());
$message = self::$error_message;
Helpers::record_warnings($e->getCode(), $e->getMessage() . " \n $url", $e->getFile(), $e->getLine());
self::$_cache[$full_url] = $resolved_url;
}
return [$resolved_url, $type, $message];
}
static function detectCircularRef(string $src, string $target)
{
if (!\array_key_exists($target, self::$svgRefs)) {
return;
}
foreach (self::$svgRefs[$target] as $ref) {
if ($ref === $src) {
throw new ImageException("Circular external SVG image reference detected.", E_WARNING);
}
self::detectCircularRef($src, $ref);
}
}
/**
* Register a temp file for the given original image file.
*
* @param string $filePath The path of the original image.
* @param string $tempPath The path of the temp file to register.
* @param string $key An optional key to register the temp file at.
*/
static function addTempImage(string $filePath, string $tempPath, string $key = "default"): void
{
if (!isset(self::$tempImages[$filePath])) {
self::$tempImages[$filePath] = [];
}
self::$tempImages[$filePath][$key] = $tempPath;
}
/**
* Get the path of a temp file registered for the given original image file.
*
* @param string $filePath The path of the original image.
* @param string $key The key the temp file is registered at.
*/
static function getTempImage(string $filePath, string $key = "default"): ?string
{
return self::$tempImages[$filePath][$key] ?? null;
}
/**
* Unlink all cached images (i.e. temporary images either downloaded
* or converted) except for the bundled "broken image"
*/
static function clear(bool $debugPng = false)
{
foreach (self::$_cache as $file) {
if ($file === self::$broken_image) {
continue;
}
if ($debugPng) {
print "[clear unlink $file]";
}
if (file_exists($file)) {
unlink($file);
}
}
foreach (self::$tempImages as $versions) {
foreach ($versions as $file) {
if ($file === self::$broken_image) {
continue;
}
if ($debugPng) {
print "[unlink temp image $file]";
}
if (file_exists($file)) {
unlink($file);
}
}
}
self::$_cache = [];
self::$tempImages = [];
self::$svgRefs = [];
}
static function detect_type($file, $context = null)
{
list(, , $type) = Helpers::dompdf_getimagesize($file, $context);
return $type;
}
static function is_broken($url)
{
return $url === self::$broken_image;
}
}
if (file_exists(realpath(__DIR__ . "/../../lib/res/broken_image.svg"))) {
Cache::$broken_image = realpath(__DIR__ . "/../../lib/res/broken_image.svg");
}
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