// KeyListTextMarshaler outputs a KeyList as plaintext, one key per line
func KeyListTextMarshaler(res cmds.Response) (io.Reader, error) {
	output := res.Output().(*KeyList)
	buf := new(bytes.Buffer)
	for _, key := range output.Keys {
		buf.WriteString(key.B58String() + "\n")
	}
	return buf, nil
}

func bootstrapMarshaler(res cmds.Response) (io.Reader, error) {
	v, ok := res.Output().(*BootstrapOutput)
	if !ok {
		return nil, u.ErrCast()
	}

	buf := new(bytes.Buffer)
	err := bootstrapWritePeers(buf, "", v.Peers)
	return buf, err
}

func guessMimeType(res cmds.Response) (string, error) {
	// Try to guess mimeType from the encoding option
	enc, found, err := res.Request().Option(cmds.EncShort).String()
	if err != nil {
		return "", err
	}
	if !found {
		return "", errors.New("no encoding option set")
	}

	return mimeTypes[enc], nil
}

func stringListMarshaler(res cmds.Response) (io.Reader, error) {
	list, ok := res.Output().(*stringList)
	if !ok {
		return nil, errors.New("failed to cast []string")
	}

	buf := new(bytes.Buffer)
	for _, s := range list.Strings {
		buf.WriteString(s)
		buf.WriteString("\n")
	}
	return buf, nil
}

func tourRunFunc(req cmds.Request, res cmds.Response) {

	cfg, err := req.InvocContext().GetConfig()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	id := tour.TopicID(cfg.Tour.Last)
	if len(req.Arguments()) > 0 {
		id = tour.TopicID(req.Arguments()[0])
	}

	w := new(bytes.Buffer)
	t, err := tourGet(id)
	if err != nil {

		// If no topic exists for this id, we handle this error right here.
		// To help the user achieve the task, we construct a response
		// comprised of...
		// 1) a simple error message
		// 2) the full list of topics

		fmt.Fprintln(w, "ERROR")
		fmt.Fprintln(w, err)
		fmt.Fprintln(w, "")
		fprintTourList(w, tour.TopicID(cfg.Tour.Last))
		res.SetOutput(w)

		return
	}

	fprintTourShow(w, t)
	res.SetOutput(w)
}

func sendResponse(w http.ResponseWriter, r *http.Request, res cmds.Response, req cmds.Request) {
	mime, err := guessMimeType(res)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	status := http.StatusOK
	// if response contains an error, write an HTTP error status code
	if e := res.Error(); e != nil {
		if e.Code == cmds.ErrClient {
			status = http.StatusBadRequest
		} else {
			status = http.StatusInternalServerError
		}
		// NOTE: The error will actually be written out by the reader below
	}

	out, err := res.Reader()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	h := w.Header()
	if res.Length() > 0 {
		h.Set(contentLengthHeader, strconv.FormatUint(res.Length(), 10))
	}

	if _, ok := res.Output().(io.Reader); ok {
		// we don't set the Content-Type for streams, so that browsers can MIME-sniff the type themselves
		// we set this header so clients have a way to know this is an output stream
		// (not marshalled command output)
		mime = ""
		h.Set(streamHeader, "1")
	}

	// if output is a channel and user requested streaming channels,
	// use chunk copier for the output
	_, isChan := res.Output().(chan interface{})
	if !isChan {
		_, isChan = res.Output().(<-chan interface{})
	}

	if isChan {
		h.Set(channelHeader, "1")
	}

	if mime != "" {
		h.Set(contentTypeHeader, mime)
	}
	h.Set(transferEncodingHeader, "chunked")

	if r.Method == "HEAD" { // after all the headers.
		return
	}

	if err := writeResponse(status, w, out); err != nil {
		if strings.Contains(err.Error(), "broken pipe") {
			log.Info("client disconnect while writing stream ", err)
			return
		}

		log.Error("error while writing stream ", err)
	}
}

func daemonFunc(req cmds.Request, res cmds.Response) {
	// let the user know we're going.
	fmt.Printf("Initializing daemon...\n")

	ctx := req.InvocContext()

	go func() {
		select {
		case <-req.Context().Done():
			fmt.Println("Received interrupt signal, shutting down...")
		}
	}()

	// check transport encryption flag.
	unencrypted, _, _ := req.Option(unencryptTransportKwd).Bool()
	if unencrypted {
		log.Warningf(`Running with --%s: All connections are UNENCRYPTED.
		You will not be able to connect to regular encrypted networks.`, unencryptTransportKwd)
		conn.EncryptConnections = false
	}

	// first, whether user has provided the initialization flag. we may be
	// running in an uninitialized state.
	initialize, _, err := req.Option(initOptionKwd).Bool()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	if initialize {

		// now, FileExists is our best method of detecting whether IPFS is
		// configured. Consider moving this into a config helper method
		// `IsInitialized` where the quality of the signal can be improved over
		// time, and many call-sites can benefit.
		if !util.FileExists(req.InvocContext().ConfigRoot) {
			err := initWithDefaults(os.Stdout, req.InvocContext().ConfigRoot)
			if err != nil {
				res.SetError(err, cmds.ErrNormal)
				return
			}
		}
	}

	// acquire the repo lock _before_ constructing a node. we need to make
	// sure we are permitted to access the resources (datastore, etc.)
	repo, err := fsrepo.Open(req.InvocContext().ConfigRoot)
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	cfg, err := ctx.GetConfig()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	// Start assembling node config
	ncfg := &core.BuildCfg{
		Online: true,
		Repo:   repo,
	}

	routingOption, _, err := req.Option(routingOptionKwd).String()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}
	if routingOption == routingOptionSupernodeKwd {
		servers, err := cfg.SupernodeRouting.ServerIPFSAddrs()
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			repo.Close() // because ownership hasn't been transferred to the node
			return
		}
		var infos []peer.PeerInfo
		for _, addr := range servers {
			infos = append(infos, peer.PeerInfo{
				ID:    addr.ID(),
				Addrs: []ma.Multiaddr{addr.Transport()},
			})
		}

		ncfg.Routing = corerouting.SupernodeClient(infos...)
	}

	node, err := core.NewNode(req.Context(), ncfg)
	if err != nil {
		log.Error("error from node construction: ", err)
		res.SetError(err, cmds.ErrNormal)
		return
	}

	printSwarmAddrs(node)

	defer func() {
		// We wait for the node to close first, as the node has children
		// that it will wait for before closing, such as the API server.
		node.Close()
//.........这里部分代码省略.........

func MessageTextMarshaler(res cmds.Response) (io.Reader, error) {
	return strings.NewReader(res.Output().(*MessageOutput).Message), nil
}