Use hash as file name to de-duplicate uploads

mediaendpoint.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"crypto/sha256"
+	"fmt"
+	"io"
 	"net/http"
 	"strings"
-	"time"
 )
 
 func HandleMedia(w http.ResponseWriter, r *http.Request) {
@@ -34,7 +36,15 @@ func HandleMedia(w http.ResponseWriter, r *http.Request) {
 			_, _ = w.Write([]byte("Failed to get file"))
 			return
 		}
-		fileName := generateRandomString(time.Now(), 15)
+		hashFile, _, _ := r.FormFile("file")
+		h := sha256.New()
+		defer func() { _ = hashFile.Close() }()
+		if _, err := io.Copy(h, hashFile); err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte("Failed to calculate hash of file"))
+			return
+		}
+		fileName := fmt.Sprintf("%x", h.Sum(nil))
 		mimeType := header.Header.Get("content-type")
 		originalName := header.Filename
 		if strings.Contains(mimeType, "jpeg") || strings.Contains(originalName, ".jpeg") || strings.Contains(originalName, ".jpg") {