src/applications/files/transform/PhabricatorFileImageTransform.php

   1 <?php
   2
   3 abstract class PhabricatorFileImageTransform extends PhabricatorFileTransform {
   4
   5   private $file;
   6   private $data;
   7   private $image;
   8   private $imageX;
   9   private $imageY;
  10
  11   /**
  12    * Get an estimate of the transformed dimensions of a file.
  13    *
  14    * @param PhabricatorFile File to transform.
  15    * @return list<int, int>|null Width and height, if available.
  16    */
  17   public function getTransformedDimensions(PhabricatorFile $file) {
  18     return null;
  19   }
  20
  21   public function canApplyTransform(PhabricatorFile $file) {
  22     if (!$file->isViewableImage()) {
  23       return false;
  24     }
  25
  26     if (!$file->isTransformableImage()) {
  27       return false;
  28     }
  29
  30     return true;
  31   }
  32
  33   protected function willTransformFile(PhabricatorFile $file) {
  34     $this->file = $file;
  35     $this->data = null;
  36     $this->image = null;
  37     $this->imageX = null;
  38     $this->imageY = null;
  39   }
  40
  41   protected function getFileProperties() {
  42     return array();
  43   }
  44
  45   protected function applyCropAndScale(
  46     $dst_w, $dst_h,
  47     $src_x, $src_y,
  48     $src_w, $src_h,
  49     $use_w, $use_h,
  50     $scale_up) {
  51
  52     // Figure out the effective destination width, height, and offsets.
  53     $cpy_w = min($dst_w, $use_w);
  54     $cpy_h = min($dst_h, $use_h);
  55
  56     // If we aren't scaling up, and are copying a very small source image,
  57     // we're just going to center it in the destination image.
  58     if (!$scale_up) {
  59       $cpy_w = min($cpy_w, $src_w);
  60       $cpy_h = min($cpy_h, $src_h);
  61     }
  62
  63     $off_x = ($dst_w - $cpy_w) / 2;
  64     $off_y = ($dst_h - $cpy_h) / 2;
  65
  66     if ($this->shouldUseImagemagick()) {
  67       $argv = array();
  68       $argv[] = '-coalesce';
  69       $argv[] = '-shave';
  70       $argv[] = $src_x.'x'.$src_y;
  71       $argv[] = '-resize';
  72
  73       if ($scale_up) {
  74         $argv[] = $dst_w.'x'.$dst_h;
  75       } else {
  76         $argv[] = $dst_w.'x'.$dst_h.'>';
  77       }
  78
  79       $argv[] = '-bordercolor';
  80       $argv[] = 'rgba(255, 255, 255, 0)';
  81       $argv[] = '-border';
  82       $argv[] = $off_x.'x'.$off_y;
  83
  84       return $this->applyImagemagick($argv);
  85     }
  86
  87     $src = $this->getImage();
  88     $dst = $this->newEmptyImage($dst_w, $dst_h);
  89
  90     $trap = new PhutilErrorTrap();
  91     $ok = @imagecopyresampled(
  92       $dst,
  93       $src,
  94       $off_x, $off_y,
  95       $src_x, $src_y,
  96       $cpy_w, $cpy_h,
  97       $src_w, $src_h);
  98     $errors = $trap->getErrorsAsString();
  99     $trap->destroy();
 100
 101     if ($ok === false) {
 102       throw new Exception(
 103         pht(
 104           'Failed to imagecopyresampled() image: %s',
 105           $errors));
 106     }
 107
 108     $data = PhabricatorImageTransformer::saveImageDataInAnyFormat(
 109       $dst,
 110       $this->file->getMimeType());
 111
 112     return $this->newFileFromData($data);
 113   }
 114
 115   protected function applyImagemagick(array $argv) {
 116     $tmp = new TempFile();
 117     Filesystem::writeFile($tmp, $this->getData());
 118
 119     $out = new TempFile();
 120
 121     $future = new ExecFuture('convert %s %Ls %s', $tmp, $argv, $out);
 122     // Don't spend more than 60 seconds resizing; just fail if it takes longer
 123     // than that.
 124     $future->setTimeout(60)->resolvex();
 125
 126     $data = Filesystem::readFile($out);
 127
 128     return $this->newFileFromData($data);
 129   }
 130
 131
 132   /**
 133    * Create a new @{class:PhabricatorFile} from raw data.
 134    *
 135    * @param string Raw file data.
 136    */
 137   protected function newFileFromData($data) {
 138     if ($this->file) {
 139       $name = $this->file->getName();
 140     } else {
 141       $name = 'default.png';
 142     }
 143
 144     $defaults = array(
 145       'canCDN' => true,
 146       'name' => $this->getTransformKey().'-'.$name,
 147     );
 148
 149     $properties = $this->getFileProperties() + $defaults;
 150
 151     return PhabricatorFile::newFromFileData($data, $properties);
 152   }
 153
 154
 155   /**
 156    * Create a new image filled with transparent pixels.
 157    *
 158    * @param int Desired image width.
 159    * @param int Desired image height.
 160    * @return resource New image resource.
 161    */
 162   protected function newEmptyImage($w, $h) {
 163     $w = (int)$w;
 164     $h = (int)$h;
 165
 166     if (($w <= 0) || ($h <= 0)) {
 167       throw new Exception(
 168         pht('Can not create an image with nonpositive dimensions.'));
 169     }
 170
 171     $trap = new PhutilErrorTrap();
 172     $img = @imagecreatetruecolor($w, $h);
 173     $errors = $trap->getErrorsAsString();
 174     $trap->destroy();
 175     if ($img === false) {
 176       throw new Exception(
 177         pht(
 178           'Unable to imagecreatetruecolor() a new empty image: %s',
 179           $errors));
 180     }
 181
 182     $trap = new PhutilErrorTrap();
 183     $ok = @imagesavealpha($img, true);
 184     $errors = $trap->getErrorsAsString();
 185     $trap->destroy();
 186     if ($ok === false) {
 187       throw new Exception(
 188         pht(
 189           'Unable to imagesavealpha() a new empty image: %s',
 190           $errors));
 191     }
 192
 193     $trap = new PhutilErrorTrap();
 194     $color = @imagecolorallocatealpha($img, 255, 255, 255, 127);
 195     $errors = $trap->getErrorsAsString();
 196     $trap->destroy();
 197     if ($color === false) {
 198       throw new Exception(
 199         pht(
 200           'Unable to imagecolorallocatealpha() a new empty image: %s',
 201           $errors));
 202     }
 203
 204     $trap = new PhutilErrorTrap();
 205     $ok = @imagefill($img, 0, 0, $color);
 206     $errors = $trap->getErrorsAsString();
 207     $trap->destroy();
 208     if ($ok === false) {
 209       throw new Exception(
 210         pht(
 211           'Unable to imagefill() a new empty image: %s',
 212           $errors));
 213     }
 214
 215     return $img;
 216   }
 217
 218
 219   /**
 220    * Get the pixel dimensions of the image being transformed.
 221    *
 222    * @return list<int, int> Width and height of the image.
 223    */
 224   protected function getImageDimensions() {
 225     if ($this->imageX === null) {
 226       $image = $this->getImage();
 227
 228       $trap = new PhutilErrorTrap();
 229       $x = @imagesx($image);
 230       $y = @imagesy($image);
 231       $errors = $trap->getErrorsAsString();
 232       $trap->destroy();
 233
 234       if (($x === false) || ($y === false) || ($x <= 0) || ($y <= 0)) {
 235         throw new Exception(
 236           pht(
 237             'Unable to determine image dimensions with '.
 238             'imagesx()/imagesy(): %s',
 239             $errors));
 240       }
 241
 242       $this->imageX = $x;
 243       $this->imageY = $y;
 244     }
 245
 246     return array($this->imageX, $this->imageY);
 247   }
 248
 249
 250   /**
 251    * Get the raw file data for the image being transformed.
 252    *
 253    * @return string Raw file data.
 254    */
 255   protected function getData() {
 256     if ($this->data !== null) {
 257       return $this->data;
 258     }
 259
 260     $file = $this->file;
 261
 262     $max_size = (1024 * 1024 * 16);
 263     $img_size = $file->getByteSize();
 264     if ($img_size > $max_size) {
 265       throw new Exception(
 266         pht(
 267           'This image is too large to transform. The transform limit is %s '.
 268           'bytes, but the image size is %s bytes.',
 269           new PhutilNumber($max_size),
 270           new PhutilNumber($img_size)));
 271     }
 272
 273     $data = $file->loadFileData();
 274     $this->data = $data;
 275     return $this->data;
 276   }
 277
 278
 279   /**
 280    * Get the GD image resource for the image being transformed.
 281    *
 282    * @return resource GD image resource.
 283    */
 284   protected function getImage() {
 285     if ($this->image !== null) {
 286       return $this->image;
 287     }
 288
 289     if (!function_exists('imagecreatefromstring')) {
 290       throw new Exception(
 291         pht(
 292           'Unable to transform image: the imagecreatefromstring() function '.
 293           'is not available. Install or enable the "gd" extension for PHP.'));
 294     }
 295
 296     $data = $this->getData();
 297     $data = (string)$data;
 298
 299     // First, we're going to write the file to disk and use getimagesize()
 300     // to determine its dimensions without actually loading the pixel data
 301     // into memory. For very large images, we'll bail out.
 302
 303     // In particular, this defuses a resource exhaustion attack where the
 304     // attacker uploads a 40,000 x 40,000 pixel PNGs of solid white. These
 305     // kinds of files compress extremely well, but require a huge amount
 306     // of memory and CPU to process.
 307
 308     $tmp = new TempFile();
 309     Filesystem::writeFile($tmp, $data);
 310     $tmp_path = (string)$tmp;
 311
 312     $trap = new PhutilErrorTrap();
 313     $info = @getimagesize($tmp_path);
 314     $errors = $trap->getErrorsAsString();
 315     $trap->destroy();
 316
 317     unset($tmp);
 318
 319     if ($info === false) {
 320       throw new Exception(
 321         pht(
 322           'Unable to get image information with getimagesize(): %s',
 323           $errors));
 324     }
 325
 326     list($width, $height) = $info;
 327     if (($width <= 0) || ($height <= 0)) {
 328       throw new Exception(
 329         pht(
 330           'Unable to determine image width and height with getimagesize().'));
 331     }
 332
 333     $max_pixels = (4096 * 4096);
 334     $img_pixels = ($width * $height);
 335
 336     if ($img_pixels > $max_pixels) {
 337       throw new Exception(
 338         pht(
 339           'This image (with dimensions %spx x %spx) is too large to '.
 340           'transform. The image has %s pixels, but transforms are limited '.
 341           'to images with %s or fewer pixels.',
 342           new PhutilNumber($width),
 343           new PhutilNumber($height),
 344           new PhutilNumber($img_pixels),
 345           new PhutilNumber($max_pixels)));
 346     }
 347
 348     $trap = new PhutilErrorTrap();
 349     $image = @imagecreatefromstring($data);
 350     $errors = $trap->getErrorsAsString();
 351     $trap->destroy();
 352
 353     if ($image === false) {
 354       throw new Exception(
 355         pht(
 356           'Unable to load image data with imagecreatefromstring(): %s',
 357           $errors));
 358     }
 359
 360     $this->image = $image;
 361     return $this->image;
 362   }
 363
 364   private function shouldUseImagemagick() {
 365     if (!PhabricatorEnv::getEnvConfig('files.enable-imagemagick')) {
 366       return false;
 367     }
 368
 369     if ($this->file->getMimeType() != 'image/gif') {
 370       return false;
 371     }
 372
 373     // Don't try to preserve the animation in huge GIFs.
 374     list($x, $y) = $this->getImageDimensions();
 375     if (($x * $y) > (512 * 512)) {
 376       return false;
 377     }
 378
 379     return true;
 380   }
 381
 382 }