Only read up to Content-Length in stream wrapper

This commit updates the stream wrapper to only read up to the number of
bytes returned in the Content-Length header when draining a stream
synchronously.

src/Handler/StreamHandler.php

@@ -119,7 +119,11 @@ private function createResponse(
         }
 
         if ($sink !== $stream) {
-            $this->drain($stream, $sink);
+            $this->drain(
+                $stream,
+                $sink,
+                $response->getHeaderLine('Content-Length')
+            );
         }
 
         $this->invokeStats($options, $request, $startTime, $response, null);
@@ -181,13 +185,27 @@ private function checkDecode(array $options, array $headers, $stream)
      *
      * @param StreamInterface $source
      * @param StreamInterface $sink
+     * @param string          $contentLength Header specifying the amount of
+     *                                       data to read.
      *
      * @return StreamInterface
      * @throws \RuntimeException when the sink option is invalid.
      */
-    private function drain(StreamInterface $source, StreamInterface $sink)
-    {
-        Psr7\copy_to_stream($source, $sink);
+    private function drain(
+        StreamInterface $source,
+        StreamInterface $sink,
+        $contentLength
+    ) {
+        // If a content-length header is provided, then stop reading once
+        // that number of bytes has been read. This can prevent infinitely
+        // reading from a stream when dealing with servers that do not honor
+        // Connection: Close headers.
+        Psr7\copy_to_stream(
+            $source,
+            $sink,
+            strlen($contentLength) > 0 ? (int) $contentLength : -1
+        );
+
         $sink->seek(0);
         $source->close();
 

tests/Handler/StreamHandlerTest.php

@@ -142,6 +142,24 @@ public function testDrainsResponseIntoSaveToBodyAtNonExistentPath()
         unlink($tmpfname);
     }
 
+    public function testDrainsResponseAndReadsOnlyContentLengthBytes()
+    {
+        Server::flush();
+        Server::enqueue([
+            new Response(200, [
+                'Foo' => 'Bar',
+                'Content-Length' => 8,
+            ], 'hi there... This has way too much data!')
+        ]);
+        $handler = new StreamHandler();
+        $request = new Request('GET', Server::$url);
+        $response = $handler($request, [])->wait();
+        $body = $response->getBody();
+        $stream = $body->detach();
+        $this->assertEquals('hi there', stream_get_contents($stream));
+        fclose($stream);
+    }
+
     public function testAutomaticallyDecompressGzip()
     {
         Server::flush();