Golang Request.Context方法代码示例

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

	cfg, err := req.Context().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)
}

//collects options and opens the fuse mountpoint
func mountFuse(req cmds.Request) error {
	cfg, err := req.Context().GetConfig()
	if err != nil {
		return fmt.Errorf("mountFuse: GetConfig() failed: %s", err)
	}

	fsdir, found, err := req.Option(ipfsMountKwd).String()
	if err != nil {
		return fmt.Errorf("mountFuse: req.Option(%s) failed: %s", ipfsMountKwd, err)
	}
	if !found {
		fsdir = cfg.Mounts.IPFS
	}

	nsdir, found, err := req.Option(ipnsMountKwd).String()
	if err != nil {
		return fmt.Errorf("mountFuse: req.Option(%s) failed: %s", ipnsMountKwd, err)
	}
	if !found {
		nsdir = cfg.Mounts.IPNS
	}

	node, err := req.Context().ConstructNode()
	if err != nil {
		return fmt.Errorf("mountFuse: ConstructNode() failed: %s", err)
	}

	err = commands.Mount(node, fsdir, nsdir)
	if err != nil {
		return err
	}
	fmt.Printf("IPFS mounted at: %s\n", fsdir)
	fmt.Printf("IPNS mounted at: %s\n", nsdir)
	return nil
}

// serveHTTPGateway collects options, creates listener, prints status message and starts serving requests
func serveHTTPGateway(req cmds.Request) (error, <-chan error) {
	cfg, err := req.Context().GetConfig()
	if err != nil {
		return fmt.Errorf("serveHTTPGateway: GetConfig() failed: %s", err), nil
	}

	gatewayMaddr, err := ma.NewMultiaddr(cfg.Addresses.Gateway)
	if err != nil {
		return fmt.Errorf("serveHTTPGateway: invalid gateway address: %q (err: %s)", cfg.Addresses.Gateway, err), nil
	}

	writable, writableOptionFound, err := req.Option(writableKwd).Bool()
	if err != nil {
		return fmt.Errorf("serveHTTPGateway: req.Option(%s) failed: %s", writableKwd, err), nil
	}
	if !writableOptionFound {
		writable = cfg.Gateway.Writable
	}

	gwLis, err := manet.Listen(gatewayMaddr)
	if err != nil {
		return fmt.Errorf("serveHTTPGateway: manet.Listen(%s) failed: %s", gatewayMaddr, err), nil
	}
	// we might have listened to /tcp/0 - lets see what we are listing on
	gatewayMaddr = gwLis.Multiaddr()

	if writable {
		fmt.Printf("Gateway (writable) server listening on %s\n", gatewayMaddr)
	} else {
		fmt.Printf("Gateway (readonly) server listening on %s\n", gatewayMaddr)
	}

	var opts = []corehttp.ServeOption{
		corehttp.VersionOption(),
		corehttp.IPNSHostnameOption(),
		corehttp.GatewayOption(writable),
	}

	if len(cfg.Gateway.RootRedirect) > 0 {
		opts = append(opts, corehttp.RedirectOption("", cfg.Gateway.RootRedirect))
	}

	node, err := req.Context().ConstructNode()
	if err != nil {
		return fmt.Errorf("serveHTTPGateway: ConstructNode() failed: %s", err), nil
	}

	errc := make(chan error)
	go func() {
		errc <- corehttp.Serve(node, gwLis.NetListener(), opts...)
		close(errc)
	}()
	return nil, errc
}

func maybeRunGC(req cmds.Request, node *core.IpfsNode) (error, <-chan error) {
	enableGC, _, err := req.Option(enableGCKwd).Bool()
	if err != nil {
		return err, nil
	}
	if !enableGC {
		return nil, nil
	}

	errc := make(chan error)
	go func() {
		errc <- corerepo.PeriodicGC(req.Context(), node)
		close(errc)
	}()
	return nil, errc
}

func setDataCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 3 {
		return "", fmt.Errorf("not enough arguments for set-data")
	}

	nd, err := req.Context().GetNode()
	if err != nil {
		return "", err
	}

	root.Data = []byte(req.Arguments()[2])

	newkey, err := nd.DAG.Add(root)
	if err != nil {
		return "", err
	}

	return newkey, nil
}

func addLinkCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 4 {
		return "", fmt.Errorf("not enough arguments for add-link")
	}

	nd, err := req.InvocContext().GetNode()
	if err != nil {
		return "", err
	}

	path := req.Arguments()[2]
	childk := key.B58KeyDecode(req.Arguments()[3])

	create, _, err := req.Option("create").Bool()
	if err != nil {
		return "", err
	}

	var createfunc func() *dag.Node
	if create {
		createfunc = func() *dag.Node {
			return &dag.Node{Data: ft.FolderPBData()}
		}
	}

	e := dagutils.NewDagEditor(nd.DAG, root)

	childnd, err := nd.DAG.Get(req.Context(), childk)
	if err != nil {
		return "", err
	}

	err = e.InsertNodeAtPath(req.Context(), path, childnd, createfunc)
	if err != nil {
		return "", err
	}

	nnode := e.GetNode()

	return nnode.Key()
}

func addLinkCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 4 {
		return "", fmt.Errorf("not enough arguments for add-link")
	}

	nd, err := req.InvocContext().GetNode()
	if err != nil {
		return "", err
	}

	path := req.Arguments()[2]
	childk := key.B58KeyDecode(req.Arguments()[3])

	parts := strings.Split(path, "/")

	nnode, err := insertNodeAtPath(req.Context(), nd.DAG, root, parts, childk)
	if err != nil {
		return "", err
	}
	return nnode.Key()
}

// commandShouldRunOnDaemon determines, from commmand details, whether a
// command ought to be executed on an IPFS daemon.
//
// It returns true if the command should be executed on a daemon and false if
// it should be executed on a client. It returns an error if the command must
// NOT be executed on either.
func commandShouldRunOnDaemon(details cmdDetails, req cmds.Request, root *cmds.Command) (bool, error) {
	path := req.Path()
	// root command.
	if len(path) < 1 {
		return false, nil
	}

	if details.cannotRunOnClient && details.cannotRunOnDaemon {
		return false, fmt.Errorf("command disabled: %s", path[0])
	}

	if details.doesNotUseRepo && details.canRunOnClient() {
		return false, nil
	}

	// at this point need to know whether daemon is running. we defer
	// to this point so that some commands dont open files unnecessarily.
	daemonLocked, err := fsrepo.LockedByOtherProcess(req.Context().ConfigRoot)
	if err != nil {
		return false, err
	}

	if daemonLocked {

		log.Info("a daemon is running...")

		if details.cannotRunOnDaemon {
			e := "ipfs daemon is running. please stop it to run this command"
			return false, cmds.ClientError(e)
		}

		return true, nil
	}

	if details.cannotRunOnClient {
		return false, cmds.ClientError("must run on the ipfs daemon")
	}

	return false, nil
}

func getBlockForKey(req cmds.Request, skey string) (blocks.Block, error) {
	if len(skey) == 0 {
		return nil, fmt.Errorf("zero length cid invalid")
	}

	n, err := req.InvocContext().GetNode()
	if err != nil {
		return nil, err
	}

	c, err := cid.Decode(skey)
	if err != nil {
		return nil, err
	}

	b, err := n.Blocks.GetBlock(req.Context(), c)
	if err != nil {
		return nil, err
	}

	log.Debugf("ipfs block: got block with key: %s", b.Cid())
	return b, nil
}

func rmLinkCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 3 {
		return "", fmt.Errorf("not enough arguments for rm-link")
	}

	nd, err := req.InvocContext().GetNode()
	if err != nil {
		return "", err
	}

	path := req.Arguments()[2]

	e := dagutils.NewDagEditor(nd.DAG, root)

	err = e.RmLink(req.Context(), path)
	if err != nil {
		return "", err
	}

	nnode := e.GetNode()

	return nnode.Key()
}

// read json objects off of the given stream, and write the objects out to
// the 'out' channel
func readStreamedJson(req cmds.Request, rr io.Reader, out chan<- interface{}) {
	defer close(out)
	dec := json.NewDecoder(rr)
	outputType := reflect.TypeOf(req.Command().Type)

	ctx := req.Context()

	for {
		v, err := decodeTypedVal(outputType, dec)
		if err != nil {
			if err != io.EOF {
				log.Error(err)
			}
			return
		}

		select {
		case <-ctx.Done():
			return
		case out <- v:
		}
	}
}

// read json objects off of the given stream, and write the objects out to
// the 'out' channel
func readStreamedJson(req cmds.Request, rr io.Reader, out chan<- interface{}) {
	defer close(out)
	dec := json.NewDecoder(rr)
	outputType := reflect.TypeOf(req.Command().Type)

	ctx := req.Context()

	for {
		v, err := decodeTypedVal(outputType, dec)
		if err != nil {
			// reading on a closed response body is as good as an io.EOF here
			if !(strings.Contains(err.Error(), "read on closed response body") || err == io.EOF) {
				log.Error(err)
			}
			return
		}

		select {
		case <-ctx.Done():
			return
		case out <- v:
		}
	}
}

func rmLinkCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 3 {
		return "", fmt.Errorf("not enough arguments for rm-link")
	}

	nd, err := req.Context().GetNode()
	if err != nil {
		return "", err
	}

	name := req.Arguments()[2]

	err = root.RemoveNodeLink(name)
	if err != nil {
		return "", err
	}

	newkey, err := nd.DAG.Add(root)
	if err != nil {
		return "", err
	}

	return newkey, nil
}

func getBlockForKey(req cmds.Request, skey string) (blocks.Block, error) {
	n, err := req.InvocContext().GetNode()
	if err != nil {
		return nil, err
	}

	if !u.IsValidHash(skey) {
		return nil, errors.New("Not a valid hash")
	}

	h, err := mh.FromB58String(skey)
	if err != nil {
		return nil, err
	}

	k := key.Key(h)
	b, err := n.Blocks.GetBlock(req.Context(), k)
	if err != nil {
		return nil, err
	}

	log.Debugf("ipfs block: got block with key: %q", b.Key())
	return b, nil
}

// getResponse decodes a http.Response to create a cmds.Response
func getResponse(httpRes *http.Response, req cmds.Request) (cmds.Response, error) {
	var err error
	res := cmds.NewResponse(req)

	contentType := httpRes.Header.Get(contentTypeHeader)
	contentType = strings.Split(contentType, ";")[0]

	lengthHeader := httpRes.Header.Get(contentLengthHeader)
	if len(lengthHeader) > 0 {
		length, err := strconv.ParseUint(lengthHeader, 10, 64)
		if err != nil {
			return nil, err
		}
		res.SetLength(length)
	}

	if len(httpRes.Header.Get(streamHeader)) > 0 {
		// if output is a stream, we can just use the body reader
		res.SetOutput(httpRes.Body)
		return res, nil

	} else if len(httpRes.Header.Get(channelHeader)) > 0 {
		// if output is coming from a channel, decode each chunk
		outChan := make(chan interface{})
		go func() {
			dec := json.NewDecoder(httpRes.Body)
			outputType := reflect.TypeOf(req.Command().Type)

			ctx := req.Context().Context

			for {
				var v interface{}
				var err error
				if outputType != nil {
					v = reflect.New(outputType).Interface()
					err = dec.Decode(v)
				} else {
					err = dec.Decode(&v)
				}
				if err != nil && err != io.EOF {
					fmt.Println(err.Error())
					return
				}

				select {
				case <-ctx.Done():
					close(outChan)
					return
				default:
				}

				if err == io.EOF {
					close(outChan)
					return
				}
				outChan <- v
			}
		}()

		res.SetOutput((<-chan interface{})(outChan))
		return res, nil
	}

	dec := json.NewDecoder(httpRes.Body)

	if httpRes.StatusCode >= http.StatusBadRequest {
		e := cmds.Error{}

		if httpRes.StatusCode == http.StatusNotFound {
			// handle 404s
			e.Message = "Command not found."
			e.Code = cmds.ErrClient

		} else if contentType == "text/plain" {
			// handle non-marshalled errors
			buf := bytes.NewBuffer(nil)
			io.Copy(buf, httpRes.Body)
			e.Message = string(buf.Bytes())
			e.Code = cmds.ErrNormal

		} else {
			// handle marshalled errors
			err = dec.Decode(&e)
			if err != nil {
				return nil, err
			}
		}

		res.SetError(e, e.Code)

	} else {
		outputType := reflect.TypeOf(req.Command().Type)
		var v interface{}

		if outputType != nil {
			v = reflect.New(outputType).Interface()
			err = dec.Decode(v)
		} else {
			err = dec.Decode(&v)
//.........这里部分代码省略.........