Adding file upload and download capabilities (#1610)

util/file/handler.go

@@ -0,0 +1,150 @@
+package file
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/micro/go-micro/errors"
+	"github.com/micro/go-micro/v2/logger"
+	"github.com/micro/go-micro/v2/server"
+	proto "github.com/micro/go-micro/v2/util/file/proto"
+	"golang.org/x/net/context"
+)
+
+// NewHandler is a handler that can be registered with a micro Server
+func NewHandler(readDir string) proto.FileHandler {
+	return &handler{
+		readDir: readDir,
+		session: &session{
+			files: make(map[int64]*os.File),
+		},
+	}
+}
+
+// RegisterHandler is a convenience method for registering a handler
+func RegisterHandler(s server.Server, readDir string) {
+	proto.RegisterFileHandler(s, NewHandler(readDir))
+}
+
+type handler struct {
+	readDir string
+	session *session
+}
+
+func (h *handler) Open(ctx context.Context, req *proto.OpenRequest, rsp *proto.OpenResponse) error {
+	path := filepath.Join(h.readDir, req.Filename)
+	file, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0666)
+	if err != nil {
+		return errors.InternalServerError("go.micro.server", err.Error())
+	}
+
+	rsp.Id = h.session.Add(file)
+	rsp.Result = true
+
+	logger.Debugf("Open %s, sessionId=%d", req.Filename, rsp.Id)
+
+	return nil
+}
+
+func (h *handler) Close(ctx context.Context, req *proto.CloseRequest, rsp *proto.CloseResponse) error {
+	h.session.Delete(req.Id)
+	logger.Debugf("Close sessionId=%d", req.Id)
+	return nil
+}
+
+func (h *handler) Stat(ctx context.Context, req *proto.StatRequest, rsp *proto.StatResponse) error {
+	path := filepath.Join(h.readDir, req.Filename)
+	fi, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		return errors.InternalServerError("go.micro.srv.file", err.Error())
+	}
+
+	if fi.IsDir() {
+		rsp.Type = "Directory"
+	} else {
+		rsp.Type = "File"
+		rsp.Size = fi.Size()
+	}
+
+	rsp.LastModified = fi.ModTime().Unix()
+	logger.Debugf("Stat %s, %#v", req.Filename, rsp)
+
+	return nil
+}
+
+func (h *handler) Read(ctx context.Context, req *proto.ReadRequest, rsp *proto.ReadResponse) error {
+	file := h.session.Get(req.Id)
+	if file == nil {
+		return errors.InternalServerError("go.micro.srv.file", "You must call open first.")
+	}
+
+	rsp.Data = make([]byte, req.Size)
+	n, err := file.ReadAt(rsp.Data, req.Offset)
+	if err != nil && err != io.EOF {
+		return errors.InternalServerError("go.micro.srv.file", err.Error())
+	}
+
+	if err == io.EOF {
+		rsp.Eof = true
+	}
+
+	rsp.Size = int64(n)
+	rsp.Data = rsp.Data[:n]
+
+	logger.Debugf("Read sessionId=%d, Offset=%d, n=%d", req.Id, req.Offset, rsp.Size)
+
+	return nil
+}
+
+func (h *handler) Write(ctx context.Context, req *proto.WriteRequest, rsp *proto.WriteResponse) error {
+	file := h.session.Get(req.Id)
+	if file == nil {
+		return errors.InternalServerError("go.micro.srv.file", "You must call open first.")
+	}
+
+	if _, err := file.WriteAt(req.GetData(), req.GetOffset()); err != nil {
+		return err
+	}
+
+	logger.Debugf("Write sessionId=%d, Offset=%d, n=%d", req.Id, req.Offset)
+
+	return nil
+}
+
+type session struct {
+	sync.Mutex
+	files   map[int64]*os.File
+	counter int64
+}
+
+func (s *session) Add(file *os.File) int64 {
+	s.Lock()
+	defer s.Unlock()
+
+	s.counter += 1
+	s.files[s.counter] = file
+
+	return s.counter
+}
+
+func (s *session) Get(id int64) *os.File {
+	s.Lock()
+	defer s.Unlock()
+	return s.files[id]
+}
+
+func (s *session) Delete(id int64) {
+	s.Lock()
+	defer s.Unlock()
+
+	if file, exist := s.files[id]; exist {
+		file.Close()
+		delete(s.files, id)
+	}
+}
+
+func (s *session) Len() int {
+	return len(s.files)
+}