add stream support

Author: mindplay-dk

src/JPEGService.php

@@ -48,6 +48,8 @@ public function __construct(string $bin_path = null, string $args = "--min 50 {I
     }
 
     /**
+     * Compress a specified JPEG file and write to a specified output path.
+     *
      * @param string $input  absolute path to input JPEG file
      * @param string $output absolute path of output JPEG file
      *
@@ -58,7 +60,7 @@ public function compress(string $input, string $output)
         $command = strtr(
             "{$this->bin_path} {$this->args}",
             [
-                "{INPUT}" => escapeshellarg($input),
+                "{INPUT}"  => escapeshellarg($input),
                 "{OUTPUT}" => escapeshellarg($output),
             ]
         );
@@ -67,4 +69,48 @@ public function compress(string $input, string $output)
 
         $process->mustRun();
     }
+
+    /**
+     * Compress JPEG data from a given input stream and write the output data
+     * either to a given stream, or to a temporary stream, which will be returned.
+     *
+     * @param resource      $input  input stream resource
+     * @param resource|null $output optional output stream resource
+     *
+     * @return resource output stream resource (file pointer will be at the start of the stream)
+     *
+     * @throws ProcessFailedException on failure to execute the command-line tool
+     */
+    public function compressStream($input, &$output = null)
+    {
+        $command = strtr(
+            "{$this->bin_path} {$this->args}",
+            [
+                "{INPUT}"  => "-",
+                "{OUTPUT}" => "-",
+            ]
+        );
+
+        $process = new Process($command);
+
+        $process->setInput($input);
+
+        if ($output === null) {
+            $output = fopen("php://temp", "w");
+        }
+
+        $status = $process->run(function ($type, $buffer) use ($output) {
+            if ($type === Process::OUT) {
+                fwrite($output, $buffer);
+            }
+        });
+
+        if ($status !== 0) {
+            throw new ProcessFailedException($process);
+        }
+
+        rewind($output);
+
+        return $output;
+    }
 }

test/test.php

@@ -5,7 +5,7 @@
 require dirname(__DIR__) . '/vendor/autoload.php';
 
 test(
-    "compress images",
+    "compress JPEG file",
     function () {
         $service = new JPEGService();
 
@@ -27,4 +27,30 @@ function () {
     }
 );
 
+test(
+    "compress JPEG stream",
+    function () {
+        $service = new JPEGService();
+
+        $input = fopen(__DIR__ . '/lena.jpg', "r");
+
+        $output = $service->compressStream($input);
+
+        $tmp_file = __DIR__ . '/lena-out.jpg';
+
+        @unlink($tmp_file); // clean up from prior test-run
+
+        $tmp = fopen($tmp_file, "w");
+
+        stream_copy_to_stream($output, $tmp);
+
+        fclose($tmp);
+
+        list($width, $height) = getimagesize($tmp_file);
+
+        eq($width, 512);
+        eq($height, 512);
+    }
+);
+
 exit(run());