metainfo URL list can be a string or list

metainfo/metainfo.go

@@ -17,7 +17,7 @@ type MetaInfo struct {
 	Comment      string        `bencode:"comment,omitempty"`
 	CreatedBy    string        `bencode:"created by,omitempty"`
 	Encoding     string        `bencode:"encoding,omitempty"`
-	URLList      []string      `bencode:"url-list,omitempty"`
+	UrlList      UrlList       `bencode:"url-list,omitempty"`
 }
 
 // Load a MetaInfo from an io.Reader. Returns a non-nil error in case of

metainfo/metainfo_test.go

@@ -116,3 +116,15 @@ func TestUnmarshal(t *testing.T) {
 	testUnmarshal(t, `d4:infoabce`, nil)
 	testUnmarshal(t, `d4:infodee`, &MetaInfo{InfoBytes: []byte("de")})
 }
+
+func TestMetainfoWithListURLList(t *testing.T) {
+	mi, err := LoadFromFile("testdata/SKODAOCTAVIA336x280_archive.torrent")
+	require.NoError(t, err)
+	assert.Len(t, mi.UrlList, 3)
+}
+
+func TestMetainfoWithStringURLList(t *testing.T) {
+	mi, err := LoadFromFile("testdata/flat-url-list.torrent")
+	require.NoError(t, err)
+	assert.Len(t, mi.UrlList, 1)
+}

metainfo/urllist.go

@@ -0,0 +1,27 @@
+package metainfo
+
+import (
+	"github.com/anacrolix/torrent/bencode"
+)
+
+type UrlList []string
+
+var (
+	_ bencode.Unmarshaler = (*UrlList)(nil)
+)
+
+func (me *UrlList) UnmarshalBencode(b []byte) error {
+	if len(b) == 0 {
+		return nil
+	}
+	if b[0] == 'l' {
+		var l []string
+		err := bencode.Unmarshal(b, &l)
+		*me = l
+		return err
+	}
+	var s string
+	err := bencode.Unmarshal(b, &s)
+	*me = []string{s}
+	return err
+}