Adding file upload and download capabilities (#1610)

util/file/client.go

@@ -0,0 +1,188 @@
+package file
+
+import (
+	"bufio"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+
+	"github.com/micro/go-micro/v2/client"
+	proto "github.com/micro/go-micro/v2/util/file/proto"
+)
+
+// Client is the client interface to access files
+type Client interface {
+	Open(filename string) (int64, error)
+	Stat(filename string) (*proto.StatResponse, error)
+	GetBlock(sessionId, blockId int64) ([]byte, error)
+	ReadAt(sessionId, offset, size int64) ([]byte, error)
+	Read(sessionId int64, buf []byte) (int, error)
+	Write(sessionId, offset int64, data []byte) error
+	Close(sessionId int64) error
+	Download(filename, saveFile string) error
+	Upload(filename, localFile string) error
+	DownloadAt(filename, saveFile string, blockId int) error
+}
+
+// NewClient returns a new Client which uses a micro Client
+func NewClient(service string, c client.Client) Client {
+	return &fc{proto.NewFileService(service, c)}
+}
+
+const (
+	blockSize = 512 * 1024
+)
+
+type fc struct {
+	c proto.FileService
+}
+
+func (c *fc) Open(filename string) (int64, error) {
+	rsp, err := c.c.Open(context.TODO(), &proto.OpenRequest{Filename: filename})
+	if err != nil {
+		return 0, err
+	}
+	return rsp.Id, nil
+}
+
+func (c *fc) Stat(filename string) (*proto.StatResponse, error) {
+	return c.c.Stat(context.TODO(), &proto.StatRequest{Filename: filename})
+}
+
+func (c *fc) GetBlock(sessionId, blockId int64) ([]byte, error) {
+	return c.ReadAt(sessionId, blockId*blockSize, blockSize)
+}
+
+func (c *fc) ReadAt(sessionId, offset, size int64) ([]byte, error) {
+	rsp, err := c.c.Read(context.TODO(), &proto.ReadRequest{Id: sessionId, Size: size, Offset: offset})
+	if err != nil {
+		return nil, err
+	}
+
+	if rsp.Eof {
+		err = io.EOF
+	}
+
+	if rsp.Data == nil {
+		rsp.Data = make([]byte, size)
+	}
+
+	if size != rsp.Size {
+		return rsp.Data[:rsp.Size], err
+	}
+
+	return rsp.Data, nil
+}
+
+func (c *fc) Read(sessionId int64, buf []byte) (int, error) {
+	b, err := c.ReadAt(sessionId, 0, int64(cap(buf)))
+	if err != nil {
+		return 0, err
+	}
+	copy(buf, b)
+	return len(b), nil
+}
+
+func (c *fc) Write(sessionId, offset int64, data []byte) error {
+	_, err := c.c.Write(context.TODO(), &proto.WriteRequest{
+		Id:     sessionId,
+		Offset: offset,
+		Data:   data})
+	return err
+}
+
+func (c *fc) Close(sessionId int64) error {
+	_, err := c.c.Close(context.TODO(), &proto.CloseRequest{Id: sessionId})
+	return err
+}
+
+func (c *fc) Download(filename, saveFile string) error {
+	return c.DownloadAt(filename, saveFile, 0)
+}
+
+func (c *fc) Upload(filename, localFile string) error {
+	file, err := os.Open(localFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	offset := 0
+	sessionId, err := c.Open(filename)
+	defer c.Close(sessionId)
+	if err != nil {
+		return err
+	}
+	reader := bufio.NewReader(file)
+	part := make([]byte, blockSize)
+
+	for {
+		count, err := reader.Read(part)
+		if err != nil {
+			break
+		}
+		err = c.Write(sessionId, int64(offset), part)
+		if err != nil {
+			return err
+		}
+		offset += count
+	}
+	if err != nil && err != io.EOF {
+		return fmt.Errorf("Error reading %v: %v", localFile, err)
+	}
+	return nil
+}
+
+func (c *fc) DownloadAt(filename, saveFile string, blockId int) error {
+	stat, err := c.Stat(filename)
+	if err != nil {
+		return err
+	}
+	if stat.Type == "Directory" {
+		return errors.New(fmt.Sprintf("%s is directory.", filename))
+	}
+
+	blocks := int(stat.Size / blockSize)
+	if stat.Size%blockSize != 0 {
+		blocks += 1
+	}
+
+	log.Printf("Download %s in %d blocks\n", filename, blocks-blockId)
+
+	file, err := os.OpenFile(saveFile, os.O_CREATE|os.O_WRONLY, 0666)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	sessionId, err := c.Open(filename)
+	if err != nil {
+		return err
+	}
+
+	for i := blockId; i < blocks; i++ {
+		buf, rerr := c.GetBlock(sessionId, int64(i))
+		if rerr != nil && rerr != io.EOF {
+			return rerr
+		}
+		if _, werr := file.WriteAt(buf, int64(i)*blockSize); werr != nil {
+			return werr
+		}
+
+		if i%((blocks-blockId)/100+1) == 0 {
+			log.Printf("Downloading %s [%d/%d] blocks", filename, i-blockId+1, blocks-blockId)
+		}
+
+		if rerr == io.EOF {
+			break
+		}
+	}
+	log.Printf("Download %s completed", filename)
+
+	c.Close(sessionId)
+
+	return nil
+}