Golang Reader.Bytes方法代码示例

// dash runs the given method and command on the dashboard.
// If args is non-nil it is encoded as the URL query string.
// If req is non-nil it is JSON-encoded and passed as the body of the HTTP POST.
// If resp is non-nil the server's response is decoded into the value pointed
// to by resp (resp must be a pointer).
func dash(meth, cmd string, args url.Values, req, resp interface{}) error {
	var r *http.Response
	var err error
	if *verbose {
		log.Println("dash", meth, cmd, args, req)
	}
	cmd = "http://" + *dashboard + "/" + cmd
	if len(args) > 0 {
		cmd += "?" + args.Encode()
	}
	switch meth {
	case "GET":
		if req != nil {
			log.Panicf("%s to %s with req", meth, cmd)
		}
		r, err = http.Get(cmd)
	case "POST":
		var body io.Reader
		if req != nil {
			b, err := json.Marshal(req)
			if err != nil {
				return err
			}
			body = bytes.NewBuffer(b)
		}
		r, err = http.Post(cmd, "text/json", body)
	default:
		log.Panicf("%s: invalid method %q", cmd, meth)
		panic("invalid method: " + meth)
	}
	if err != nil {
		return err
	}

	defer r.Body.Close()
	body := new(bytes.Buffer)
	if _, err := body.ReadFrom(r.Body); err != nil {
		return err
	}

	// Read JSON-encoded Response into provided resp
	// and return an error if present.
	var result = struct {
		Response interface{}
		Error    string
	}{
		// Put the provided resp in here as it can be a pointer to
		// some value we should unmarshal into.
		Response: resp,
	}
	if err = json.Unmarshal(body.Bytes(), &result); err != nil {
		log.Printf("json unmarshal %#q: %s\n", body.Bytes(), err)
		return err
	}
	if result.Error != "" {
		return errors.New(result.Error)
	}

	return nil
}

func readFull(data io.Reader) ([]byte, error) {
	switch data := data.(type) {
	case memoryBuffer:
		return data.Bytes(), nil
	default:
		return ioutil.ReadAll(data)
	}
	panic("not reached")
	return nil, nil
}

// Upload uploads a file to a B2 bucket. If mimeType is "", "b2/x-auto" will be used.
//
// Concurrent calls to Upload will use separate upload URLs, but consequent ones
// will attempt to reuse previously obtained ones to save b2_get_upload_url calls.
// Upload URL failures are handled transparently.
//
// Since the B2 API requires a SHA1 header, normally the file will first be read
// entirely into a memory buffer. Two cases avoid the memory copy: if r is a
// bytes.Buffer, the SHA1 will be computed in place; otherwise, if r implements io.Seeker
// (like *os.File and *bytes.Reader), the file will be read twice, once to compute
// the SHA1 and once to upload.
//
// If a file by this name already exist, a new version will be created.
func (b *Bucket) Upload(r io.Reader, name, mimeType string) (*FileInfo, error) {
	var body io.ReadSeeker
	switch r := r.(type) {
	case *bytes.Buffer:
		defer r.Reset() // we are expected to consume it
		body = bytes.NewReader(r.Bytes())
	case io.ReadSeeker:
		body = r
	default:
		b, err := ioutil.ReadAll(r)
		if err != nil {
			return nil, err
		}
		body = bytes.NewReader(b)
	}

	h := sha1.New()
	length, err := io.Copy(h, body)
	if err != nil {
		return nil, err
	}
	sha1Sum := hex.EncodeToString(h.Sum(nil))

	var fi *FileInfo
	for i := 0; i < 5; i++ {
		if _, err = body.Seek(0, io.SeekStart); err != nil {
			return nil, err
		}

		fi, err = b.UploadWithSHA1(body, name, mimeType, sha1Sum, length)
		if err == nil {
			break
		}
	}
	return fi, err
}

// dash is copied from the builder binary. It runs the given method and command on the dashboard.
//
// TODO(bradfitz,adg): unify this somewhere?
//
// If args is non-nil it is encoded as the URL query string.
// If req is non-nil it is JSON-encoded and passed as the body of the HTTP POST.
// If resp is non-nil the server's response is decoded into the value pointed
// to by resp (resp must be a pointer).
func dash(meth, cmd string, args url.Values, req, resp interface{}) error {
	const builderVersion = 1 // keep in sync with dashboard/app/build/handler.go
	argsCopy := url.Values{"version": {fmt.Sprint(builderVersion)}}
	for k, v := range args {
		if k == "version" {
			panic(`dash: reserved args key: "version"`)
		}
		argsCopy[k] = v
	}
	var r *http.Response
	var err error
	cmd = dashBase() + cmd + "?" + argsCopy.Encode()
	switch meth {
	case "GET":
		if req != nil {
			log.Panicf("%s to %s with req", meth, cmd)
		}
		r, err = http.Get(cmd)
	case "POST":
		var body io.Reader
		if req != nil {
			b, err := json.Marshal(req)
			if err != nil {
				return err
			}
			body = bytes.NewBuffer(b)
		}
		r, err = http.Post(cmd, "text/json", body)
	default:
		log.Panicf("%s: invalid method %q", cmd, meth)
		panic("invalid method: " + meth)
	}
	if err != nil {
		return err
	}
	defer r.Body.Close()
	if r.StatusCode != http.StatusOK {
		return fmt.Errorf("bad http response: %v", r.Status)
	}
	body := new(bytes.Buffer)
	if _, err := body.ReadFrom(r.Body); err != nil {
		return err
	}

	// Read JSON-encoded Response into provided resp
	// and return an error if present.
	var result = struct {
		Response interface{}
		Error    string
	}{
		// Put the provided resp in here as it can be a pointer to
		// some value we should unmarshal into.
		Response: resp,
	}
	if err = json.Unmarshal(body.Bytes(), &result); err != nil {
		log.Printf("json unmarshal %#q: %s\n", body.Bytes(), err)
		return err
	}
	if result.Error != "" {
		return errors.New(result.Error)
	}

	return nil
}