+StreamUtil::copyToStream()

Author: codemasher

src/StreamUtil.php

@@ -12,10 +12,13 @@
 
 use InvalidArgumentException;
 use Psr\Http\Message\StreamInterface;
+use RuntimeException;
 use Throwable;
 use function in_array;
+use function min;
 use function preg_match;
 use function str_contains;
+use function strlen;
 use function substr;
 
 /**
@@ -130,4 +133,37 @@ public static function getContents(StreamInterface $stream):?string{
 		return $data;
 	}
 
+	/**
+	 * Copies a stream to another stream, starting from the current position of the source stream,
+	 * reading to the end or until the given maxlength is hit.
+	 *
+	 * Throws if the source is not readable or the destination not writable.
+	 *
+	 * @throws \RuntimeException
+	 */
+	public static function copyToStream(StreamInterface $source, StreamInterface $destination, int $maxLength = null):int{
+
+		if(!$source->isReadable() || !$destination->isWritable()){
+			throw new RuntimeException('$source must be readable and $destination must be writable');
+		}
+
+		$remaining = ($maxLength ?? ($source->getSize() - $source->tell()));
+		$bytesRead = 0;
+
+		while($remaining > 0 && !$source->eof()){
+			$chunk      = $source->read(min(8192, $remaining));
+			$length     = strlen($chunk);
+			$bytesRead += $length;
+
+			if($length === 0){
+				break;
+			}
+
+			$remaining -= $length;
+			$destination->write($chunk);
+		}
+
+		return $bytesRead;
+	}
+
 }

tests/StreamUtilTest.php

@@ -13,11 +13,12 @@
 use chillerlan\HTTP\Utils\StreamUtil;
 use InvalidArgumentException;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 use function fclose;
 use function fopen;
 use function stream_get_meta_data;
+use function strlen;
 use function substr;
-use function var_dump;
 
 /**
  *
@@ -85,4 +86,55 @@ public function testGetContentsFromUnreadableStream():void{
 		$this::assertNull(StreamUtil::getContents($stream));
 	}
 
+	public function testCopyToStream():void{
+		$content = 'teststream';
+
+		$streamA = $this->streamFactory->createStream($content);
+		$streamB = $this->streamFactory->createStream();
+
+		$bytesRead = StreamUtil::copyToStream($streamA, $streamB);
+
+		$this::assertSame(strlen($content), $bytesRead);
+		$this::assertSame($content, (string)$streamB); // -> "teststream"
+	}
+
+	public function testCopyToStreamWithMaxlength():void{
+		$content   = 'teststream';
+		$maxlength = 4;
+
+		$streamA   = $this->streamFactory->createStream($content);
+		$streamB   = $this->streamFactory->createStream();
+
+		$bytesRead = StreamUtil::copyToStream($streamA, $streamB, $maxlength);
+
+		$this::assertSame($maxlength, $bytesRead);
+		$this::assertSame(substr($content, 0, $maxlength), (string)$streamB); // -> "test"
+	}
+
+	public function testCopyToStreamFromCurrentPosition():void{
+		$content  = 'teststream';
+		$position = 4;
+
+		$streamA  = $this->streamFactory->createStream($content);
+		$streamB  = $this->streamFactory->createStream();
+
+		$streamA->seek($position);
+		$pos = $streamA->tell();
+
+		$bytesRead = StreamUtil::copyToStream($streamA, $streamB);
+
+		$this::assertSame((strlen($content) - $pos), $bytesRead);
+		$this::assertSame(substr($content, $position), (string)$streamB); // -> "stream"
+	}
+
+	public function testCopyToStreamException():void{
+		$this->expectException(RuntimeException::class);
+		$this->expectExceptionMessage('$source must be readable and $destination must be writable');
+
+		$streamA = $this->streamFactory->createStreamFromResource(fopen(__DIR__.'/fopen-test.txt', 'a'));
+		$streamB = $this->streamFactory->createStream();
+
+		StreamUtil::copyToStream($streamA, $streamB);
+	}
+
 }