From c422436a295dd6ad709521c0c0828369e2c84597 Mon Sep 17 00:00:00 2001
From: Ronnie Roller <rroller@snapchat.com>
Date: Sat, 8 Feb 2020 17:56:29 -0800
Subject: [PATCH] use http.ServeFile

---
 src/media/fetch.go |  2 +-
 src/media/serve.go | 29 ++++++++++-------------------
 2 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/src/media/fetch.go b/src/media/fetch.go
index d5e2147..0ba05f5 100644
--- a/src/media/fetch.go
+++ b/src/media/fetch.go
@@ -76,7 +76,7 @@ func FetchMediaApi(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// just take the first one
-	streamFileToClientById(w, response.Medias[0].Id)
+	streamFileToClientById(w, r, response.Medias[0].Id)
 }
 
 func getMediaResults(r *http.Request) (MediaResults, error) {
diff --git a/src/media/serve.go b/src/media/serve.go
index 7acffb0..2e88d42 100644
--- a/src/media/serve.go
+++ b/src/media/serve.go
@@ -2,11 +2,9 @@ package media
 
 import (
 	"github.com/rs/zerolog/log"
-	"io"
 	"net/http"
 	"os"
 	"path/filepath"
-	"strconv"
 )
 
 /**
@@ -25,25 +23,25 @@ func ServeMedia(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	streamFileToClientById(w, id)
+	streamFileToClientById(w, r, id)
 }
 
-func streamFileToClientById(w http.ResponseWriter, id string) {
+func streamFileToClientById(w http.ResponseWriter, r *http.Request, id string) {
 	filename, err := getFileFromId(id)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 	}
 
-	streamFileToClient(w, filename)
+	streamFileToClient(w, r, filename)
 }
 
-func streamFileToClient(writer http.ResponseWriter, filename string) {
+func streamFileToClient(w http.ResponseWriter, r *http.Request, filename string) {
 	// Check if file exists and open
 	Openfile, err := os.Open(filename)
 	defer Openfile.Close() //Close after function return
 	if err != nil {
 		//File not found, send 404
-		http.Error(writer, "File not found.", 404)
+		http.Error(w, "File not found.", 404)
 		return
 	}
 
@@ -53,30 +51,23 @@ func streamFileToClient(writer http.ResponseWriter, filename string) {
 	//Copy the headers into the FileHeader buffer
 	if _, err = Openfile.Read(fileHeader); err != nil {
 		log.Error().Msgf("File not found, couldn't open for reading at %s %v", filename, err)
-		http.Error(writer, "File not found", 404)
+		http.Error(w, "File not found", 404)
 		return
 	}
 
 	// Get content type of file
 	fileContentType := http.DetectContentType(fileHeader)
 
-	// Get the file size as a string
-	fileStat, _ := Openfile.Stat()
-	fileSize := strconv.FormatInt(fileStat.Size(), 10)
-
 	// Send the headers
-	writer.Header().Set("Content-Disposition", "filename="+filepath.Base(filename))
-	writer.Header().Set("Content-Type", fileContentType)
-	writer.Header().Set("Content-Length", fileSize)
+	w.Header().Set("Content-Disposition", "filename="+filepath.Base(filename))
+	w.Header().Set("Content-Type", fileContentType)
 
 	// Send the file
 	// We read n bytes from the file already, so we reset the offset back to 0
 	if _, err = Openfile.Seek(0, 0); err != nil {
 		log.Error().Msgf("Error seeking into file %s %v", filename, err)
-		http.Error(writer, "File not found", 404)
+		http.Error(w, "File not found", 404)
 		return
 	}
-
-	// Copy the file to the client
-	_, _ = io.Copy(writer, Openfile)
+	http.ServeFile(w, r, filename)
 }