Fix Image::fromString to support PNG and WebP files

- Add missing fromString methods to PNG and WebP classes
- Update Image::fromString to read image size and MIME type with getimagesizefromstring
- Update and refactor related tests

Author: klaari

src/Format/PNG.php

@@ -104,6 +104,16 @@ public static function fromFile($filename)
         return new self(file_get_contents($filename));
     }
 
+    /**
+     * @param $string
+     *
+     * @return PNG
+     */
+    public static function fromString($string)
+    {
+        return new self($string);
+    }
+
     /**
      * @param string $contents
      *

src/Format/WebP.php

@@ -144,10 +144,19 @@ public function getIptc()
      */
     public static function fromFile($filename)
     {
-        // var_dump($filename);
         return new self(file_get_contents($filename));
     }
 
+    /**
+     * @param $string
+     *
+     * @return PNG
+     */
+    public static function fromString($string)
+    {
+        return new self($string);
+    }
+
     /**
      * @param string $contents
      *

src/Image.php

@@ -210,29 +210,31 @@ public static function fromFile($fileName)
      *
      * @return JPEG|WebP|PNG|false
      */
+
     public static function fromString($string)
     {
-        $len = strlen($string);
+        $imageInfo = getimagesizefromstring($string);
 
-        // try JPEG
-        if ($len >= 2) {
-            if (JPEG::SOI === substr($string, 0, 2)) {
-                return JPEG::fromString($string);
-            }
+        if (!$imageInfo) {
+            return false;
         }
 
-        // try WebP
-        if ($len >= 4) {
-            if ('RIFF' === substr($string, 0, 4) && 'WEBP' === substr($string, 8, 4)) {
-                return WebP::fromString($string);
-            }
-        }
+        $width = $imageInfo[0];
+        $height = $imageInfo[1];
+        $mime = $imageInfo['mime'];
 
-        // try PNG
-        if ($len >= 8) {
-            if (PNG::SIGNATURE === substr($string, 0, 8)) {
-                return PNG::fromString($string);
-            }
+        $mimeToClass = [
+            'image/jpeg' => JPEG::class,
+            'image/png'  => PNG::class,
+            'image/webp' => WebP::class,
+        ];
+
+        if (isset($mimeToClass[$mime])) {
+            $class = $mimeToClass[$mime];
+            $image = $class::fromString($string);
+            $image->width = $width;
+            $image->height = $height;
+            return $image;
         }
 
         return false;

tests/Format/JPEGTest.php

@@ -1,53 +1,58 @@
 <?php
-
 namespace CSD\Image\Tests\Format;
 
 use CSD\Image\Format\JPEG;
 use CSD\Image\Metadata\Xmp;
 
 /**
- * @author Daniel Chesterton <daniel@chestertondevelopment.com>
- *
  * @coversDefaultClass \CSD\Image\Format\JPEG
  */
 class JPEGTest extends \PHPUnit\Framework\TestCase
 {
     /**
-     * Test that JPEG can read XMP embedded with Photo Mechanic.
+     * Data provider for testGetXmp method.
+     *
+     * @return array
      */
-    public function testGetXmpPhotoMechanic()
+    public function providerTestGetXmp()
     {
-        $jpeg = JPEG::fromFile(__DIR__ . '/../Fixtures/metapm.jpg');
-
-        $xmp = $jpeg->getXmp();
-
-        $this->assertInstanceOf(Xmp::class, $xmp);
-        $this->assertSame('Headline', $xmp->getHeadline());
+        return [
+            // [method, filename, expectedHeadline]
+            ['fromFile', 'metapm.jpg', 'Headline'],
+            ['fromString', 'metapm.jpg', 'Headline'],
+            ['fromFile', 'metaphotoshop.jpg', 'Headline'],
+            ['fromString', 'metaphotoshop.jpg', 'Headline'],
+            ['fromFile', 'nometa.jpg', null],
+            ['fromString', 'nometa.jpg', null],
+        ];
     }
 
     /**
-     * Test that JPEG can read XMP embedded with Photoshop.
+     * Test that JPEG can read XMP data using both fromFile and fromString methods.
+     *
+     * @dataProvider providerTestGetXmp
+     *
+     * @param string      $method          The method to use ('fromFile' or 'fromString')
+     * @param string      $filename        The filename of the test image
+     * @param string|null $expectedHeadline The expected headline in the XMP data
      */
-    public function testGetXmpPhotoshop()
+    public function testGetXmp($method, $filename, $expectedHeadline)
     {
-        $jpeg = JPEG::fromFile(__DIR__ . '/../Fixtures/metaphotoshop.jpg');
-
-        $xmp = $jpeg->getXmp();
+        $filePath = __DIR__ . '/../Fixtures/' . $filename;
 
-        $this->assertInstanceOf(Xmp::class, $xmp);
-        $this->assertSame('Headline', $xmp->getHeadline());
-    }
-
-    /**
-     * Test that JPEG class returns an empty XMP object when there is no XMP data.
-     */
-    public function testGetXmpNoMeta()
-    {
-        $jpeg = JPEG::fromFile(__DIR__ . '/../Fixtures/nometa.jpg');
+        if ($method === 'fromFile') {
+            $jpeg = JPEG::fromFile($filePath);
+        } elseif ($method === 'fromString') {
+            $string = file_get_contents($filePath);
+            $jpeg = JPEG::fromString($string);
+        } else {
+            throw new \InvalidArgumentException("Invalid method: $method");
+        }
 
         $xmp = $jpeg->getXmp();
 
         $this->assertInstanceOf(Xmp::class, $xmp);
-        $this->assertNull($xmp->getHeadline());
+        $this->assertSame($expectedHeadline, $xmp->getHeadline());
     }
 }
+