middleware : add torrent approval package

this makes it possible to specify a torrent whitelist/blacklist in the
configuration file based on their hexadecimal hash.

Fixes #375

Signed-off-by: Pierre-Alain TORET <pierre-alain.toret@protonmail.com>

middleware/torrentapproval/torrentapproval_test.go

@@ -0,0 +1,78 @@
+package torrentapproval
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"testing"
+
+	"github.com/chihaya/chihaya/bittorrent"
+	"github.com/stretchr/testify/require"
+)
+
+var cases = []struct {
+	cfg      Config
+	ih       string
+	approved bool
+}{
+	// Infohash is whitelisted
+	{
+		Config{
+			Whitelist: []string{"3532cf2d327fad8448c075b4cb42c8136964a435"},
+		},
+		"3532cf2d327fad8448c075b4cb42c8136964a435",
+		true,
+	},
+	// Infohash is not whitelisted
+	{
+		Config{
+			Whitelist: []string{"3532cf2d327fad8448c075b4cb42c8136964a435"},
+		},
+		"4532cf2d327fad8448c075b4cb42c8136964a435",
+		false,
+	},
+	// Infohash is not blacklisted
+	{
+		Config{
+			Blacklist: []string{"3532cf2d327fad8448c075b4cb42c8136964a435"},
+		},
+		"4532cf2d327fad8448c075b4cb42c8136964a435",
+		true,
+	},
+	// Infohash is blacklisted
+	{
+		Config{
+			Blacklist: []string{"3532cf2d327fad8448c075b4cb42c8136964a435"},
+		},
+		"3532cf2d327fad8448c075b4cb42c8136964a435",
+		false,
+	},
+}
+
+func TestHandleAnnounce(t *testing.T) {
+	for _, tt := range cases {
+		t.Run(fmt.Sprintf("testing hash %s", tt.ih), func(t *testing.T) {
+			h, err := NewHook(tt.cfg)
+			require.Nil(t, err)
+
+			ctx := context.Background()
+			req := &bittorrent.AnnounceRequest{}
+			resp := &bittorrent.AnnounceResponse{}
+
+			hashbytes, err := hex.DecodeString(tt.ih)
+			require.Nil(t, err)
+
+			hashinfo := bittorrent.InfoHashFromBytes(hashbytes)
+
+			req.InfoHash = hashinfo
+
+			nctx, err := h.HandleAnnounce(ctx, req, resp)
+			require.Equal(t, ctx, nctx)
+			if tt.approved == true {
+				require.Nil(t, err)
+			} else {
+				require.NotNil(t, err)
+			}
+		})
+	}
+}