Added Range support to FileBackend::streamFile()

* Added HTTP options headers parameter to streamFile().
* Refactored doStreamFile() to either call StreamFile::stream()
  or delagate that to the subclass. SwiftFileBackend now relays
  the full Swift response rather than manually making the headers.
  This also makes Range headers easy to support.
* Made use of this in img_auth.php for performance on private wikis.
* Elimate stat call in streamFile() for Swift if "headers" is empty.
* Refactored StreamFile a bit to inject request headers instead
  of using the $_SERVER global. A header options parameter is used
  instead, which also supports Range.
* Removed now unused prepareForStream().
* Cleaned up streamFile() unit tests.

Change-Id: I2ccbcbca6caabb8cf65bd6b3084cede2e6ea628a

1 files changed, 9 insertions, 1 deletions

diff --git a/img_auth.php b/img_auth.php
index d63618817a19..fa1609f96398 100644
--- a/img_auth.php
+++ b/img_auth.php
@@ -162,13 +162,21 @@ function wfImageAuthMain() {
 		}
 	}
 
+	$options = []; // HTTP header options
+	if ( isset( $_SERVER['HTTP_RANGE'] ) ) {
+		$options['range'] = $_SERVER['HTTP_RANGE'];
+	}
+	if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
+		$options['if-modified-since'] = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
+	}
+
 	if ( $request->getCheck( 'download' ) ) {
 		$headers[] = 'Content-Disposition: attachment';
 	}
 
 	// Stream the requested file
 	wfDebugLog( 'img_auth', "Streaming `" . $filename . "`." );
-	$repo->streamFile( $filename, $headers );
+	$repo->streamFile( $filename, $headers, $options );
 }
 
 /**