Fix blob missing from disk (but still in database)

qa-include/app/blobs.php

@@ -133,7 +133,11 @@
 	{
 		if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }
 
-		return file_get_contents(qa_get_blob_filename($blobid, $format));
+		$filename = qa_get_blob_filename($blobid, $format);
+		if (is_readable($filename))
+			return file_get_contents($filename);
+		else
+			return null;
 	}
 
 

qa-include/qa-blob.php

@@ -47,7 +47,7 @@ qa_db_connect('qa_blob_db_fail_handler');
 
 $blob = qa_read_blob(qa_get('qa_blobid'));
 
-if (isset($blob)) {
+if (isset($blob) && isset($blob['content'])) {
 	// allows browsers and proxies to cache the blob (30 days)
 	header('Cache-Control: max-age=2592000, public');