From ff46a72f5317599c403f23a1a892fd746ffee91f Mon Sep 17 00:00:00 2001
From: Arseny Balobanov <verytable@yandex.ru>
Date: Thu, 23 Apr 2020 19:42:40 +0300
Subject: [PATCH] io-lecture: replace f.Read(...) with io.ReadAtLeast(f, ...)
 in http chunking solution

---
 lectures/09-io/sendfile/main.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lectures/09-io/sendfile/main.go b/lectures/09-io/sendfile/main.go
index f2608ec..69e3678 100644
--- a/lectures/09-io/sendfile/main.go
+++ b/lectures/09-io/sendfile/main.go
@@ -40,8 +40,8 @@ func copyHandler(w http.ResponseWriter, r *http.Request) {
 	defer func() { _ = f.Close() }()
 
 	// Infer the Content-Type of the file.
-	filePrefix := make([]byte, 512)
-	_, _ = f.Read(filePrefix)
+	filePrefix := make([]byte, 1024)
+	_, _ = io.ReadAtLeast(f, filePrefix, 512)
 	contentType := http.DetectContentType(filePrefix)
 
 	// Get the file size.