Add announce and download commands to cmd/torrent

cmd/torrent/announce.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/anacrolix/tagflag"
+	"github.com/davecgh/go-spew/spew"
+
+	"github.com/anacrolix/torrent"
+	"github.com/anacrolix/torrent/tracker"
+)
+
+func announceErr(args []string, parent *tagflag.Parser) error {
+	var flags struct {
+		tagflag.StartPos
+		Tracker  string
+		InfoHash torrent.InfoHash
+	}
+	tagflag.ParseArgs(&flags, args, tagflag.Parent(parent))
+	response, err := tracker.Announce{
+		TrackerUrl: flags.Tracker,
+		Request: tracker.AnnounceRequest{
+			InfoHash: flags.InfoHash,
+			Port:     uint16(torrent.NewDefaultClientConfig().ListenPort),
+		},
+	}.Do()
+	if err != nil {
+		return fmt.Errorf("doing announce: %w", err)
+	}
+	spew.Dump(response)
+	return nil
+}

cmd/torrent/main.go

@@ -178,7 +178,24 @@ func main() {
 }
 
 func mainErr() error {
-	tagflag.Parse(&flags)
+	var flags struct {
+		tagflag.StartPos
+		Command string
+		Args    tagflag.ExcessArgs
+	}
+	parser := tagflag.Parse(&flags, tagflag.ParseIntermixed(false))
+	switch flags.Command {
+	case "announce":
+		return announceErr(flags.Args, parser)
+	case "download":
+		return downloadErr(flags.Args, parser)
+	default:
+		return fmt.Errorf("unknown command %q", flags.Command)
+	}
+}
+
+func downloadErr(args []string, parent *tagflag.Parser) error {
+	tagflag.ParseArgs(&flags, args, tagflag.Parent(parent))
 	defer envpprof.Stop()
 	clientConfig := torrent.NewDefaultClientConfig()
 	clientConfig.DisableAcceptRateLimiting = true