Preserve uploaded file extensions

server/media/media_test.go

@@ -3,6 +3,8 @@ package media
 import (
 	"strings"
 	"testing"
+
+	"github.com/tinode/chat/server/store/types"
 )
 
 func TestMatchCORSOrigin(t *testing.T) {
@@ -237,3 +239,71 @@ func TestExtensionByMimeType(t *testing.T) {
 		}
 	}
 }
+
+func TestMimeTypeForUploadPrefersContainerFilename(t *testing.T) {
+	cases := []struct {
+		name     string
+		detect   string
+		client   string
+		filename string
+		want     string
+	}{
+		{
+			name:     "m4a misdetected as mp4",
+			detect:   "video/mp4",
+			filename: "voice.m4a",
+			want:     "audio/x-m4a",
+		},
+		{
+			name:     "xlsx misdetected as zip",
+			detect:   "application/zip",
+			filename: "iOS任务拆解.xlsx",
+			want:     "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+		},
+		{
+			name:     "client content type fallback",
+			detect:   "application/octet-stream",
+			client:   "image/jfif",
+			filename: "thumb",
+			want:     "image/jfif",
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := MimeTypeForUpload(tc.detect, tc.client, tc.filename); got != tc.want {
+				t.Fatalf("MimeTypeForUpload()=%q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestFileURLNamePrefersOriginalExtension(t *testing.T) {
+	cases := []struct {
+		name string
+		def  *types.FileDef
+		want string
+	}{
+		{
+			name: "voice keeps m4a extension",
+			def:  &types.FileDef{ObjHeader: types.ObjHeader{Id: "file123"}, MimeType: "video/mp4", OriginalName: "voice.m4a"},
+			want: "file123.m4a",
+		},
+		{
+			name: "xlsx keeps xlsx extension",
+			def:  &types.FileDef{ObjHeader: types.ObjHeader{Id: "sheet123"}, MimeType: "application/zip", OriginalName: "iOS任务拆解.xlsx"},
+			want: "sheet123.xlsx",
+		},
+		{
+			name: "falls back to mime extension",
+			def:  &types.FileDef{ObjHeader: types.ObjHeader{Id: "image123"}, MimeType: "image/jpeg"},
+			want: "image123.jpg",
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := FileURLName(tc.def); got != tc.want {
+				t.Fatalf("FileURLName()=%q, want %q", got, tc.want)
+			}
+		})
+	}
+}