fix:修复

utils/file/base64.go

@@ -2,16 +2,17 @@ package file
 
 import (
 	"encoding/base64"
+	"net/http"
 	"strings"
 )
 
-func FileBase64ToByte(fileData string) ([]byte, error) {
+func FileBase64ToByte(fileData string) ([]byte, string, error) {
 	RBase64Point := strings.LastIndex(fileData, ";base64,") + 8
 	fileDataStr := fileData[RBase64Point:]
 	dist, err := base64.StdEncoding.DecodeString(fileDataStr)
-
 	if err != nil {
-		return nil, err
+		return nil, "", err
 	}
-	return dist, nil
+	contentType := http.DetectContentType(dist)
+	return dist, contentType, nil
 }