From 32e6b9b9094e2a4fbd82c9eb61d181afe532c3e2 Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Wed, 10 Jan 2018 10:55:07 +0300
Subject: [PATCH] Write to .part file while writing

---
 src/uploader/main.go | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/uploader/main.go b/src/uploader/main.go
index 74be1fe..ed39c3d 100644
--- a/src/uploader/main.go
+++ b/src/uploader/main.go
@@ -57,29 +57,35 @@ func upload(w http.ResponseWriter, r *http.Request) {
 		log.Println(r.RemoteAddr, "non file form field")
 		return
 	}
+	h, err := blake2s.New256(nil)
+	if err != nil {
+		panic(err)
+	}
 	fn := time.Now().Format(time.RFC3339Nano)
-	fd, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE, 0600)
+	fd, err := os.OpenFile(fn+".part", os.O_WRONLY|os.O_CREATE, 0600)
 	if err != nil {
 		log.Println(r.RemoteAddr, fn, p.FileName(), err)
 		return
 	}
-	defer fd.Close()
-	h, err := blake2s.New256(nil)
-	if err != nil {
-		panic(err)
-	}
 	fdBuf := bufio.NewWriterSize(fd, WriteBufSize)
 	mw := io.MultiWriter(fdBuf, h)
 	n, err := io.Copy(mw, p)
 	if err != nil {
 		log.Println(r.RemoteAddr, fn, p.FileName(), err)
+		fd.Close()
 		return
 	}
 	if err = fdBuf.Flush(); err != nil {
 		log.Println(r.RemoteAddr, fn, p.FileName(), err)
+		fd.Close()
 		return
 	}
+	fd.Close()
 	sum := hex.EncodeToString(h.Sum(nil))
+	if err = os.Rename(fn+".part", fn); err != nil {
+		log.Println(r.RemoteAddr, fn, p.FileName(), n, sum, err)
+		return
+	}
 	fmt.Fprintf(w, "bytes: %d\nBLAKE2s: %s\n", n, sum)
 	log.Println(r.RemoteAddr, fn, p.FileName(), n, sum)
 }
-- 
2.44.0