From c22e314d80e33b8f7d5c990995ad841d8359f24c Mon Sep 17 00:00:00 2001
From: Jacob Melton <jmelton116@gmail.com>
Date: Wed, 30 Sep 2015 10:31:40 -0400
Subject: [PATCH] Add a check to see if we already hit EOF on Read

---
 upload.go | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/upload.go b/upload.go
index d2e0504..e053ecb 100644
--- a/upload.go
+++ b/upload.go
@@ -140,10 +140,19 @@ func processUpload(upReq UploadRequest) (upload Upload, err error) {
 	barename, extension := barePlusExt(upReq.filename)
 
 	// Pull the first 512 bytes off for use in MIME detection if needed
+	// If the file uploaded fit in 512 or less bytes, then the Read will have returned EOF
+	// In this situation we don't want to create a MultiReader as this will cause no EOF to be emitted
+	// by the resulting io.Reader. Instead we just create a new reader from the bytes we already read,
+	// and only create a multiReader if we have yet to get EOF from the first read.
+	var fileSrc io.Reader
 	header := make([]byte, 512)
 	n, err := upReq.src.Read(header)
-	if n == 0 || err != nil {
+	if n == 0 {
 		return
+	} else if err == io.EOF {
+		fileSrc = bytes.NewReader(header[:n])
+	} else {
+		fileSrc = io.MultiReader(bytes.NewReader(header), upReq.src)
 	}
 
 	if upReq.randomBarename || len(barename) == 0 {
@@ -199,10 +208,7 @@ func processUpload(upReq UploadRequest) (upload Upload, err error) {
 
 	metadataWrite(upload.Filename, &upload)
 
-	// Make a multi-reader from the header and the remainder of bytes
-	// in the upReq.src io.Reader
-	src := io.MultiReader(bytes.NewReader(header), upReq.src)
-	bytes, err := io.Copy(dst, src)
+	bytes, err := io.Copy(dst, fileSrc)
 	if err != nil {
 		return
 	} else if bytes == 0 {