Implement preserve

client.go

@@ -315,14 +315,38 @@ func (a *Client) CopyFromRemotePassThru(
 	remotePath string,
 	passThru PassThru,
 ) error {
+	_, err := a.copyFromRemote(ctx, w, remotePath, passThru, false)
+
+	return err
+}
+
+// CopyFroRemoteFileInfos copies a file from the remote to a given writer and return a FileInfos struct
+// containing information about the file such as permissions, the file size, modification time and access time
+func (a *Client) CopyFromRemoteFileInfos(
+	ctx context.Context,
+	w io.Writer,
+	remotePath string,
+	passThru PassThru,
+) (*FileInfos, error) {
+	return a.copyFromRemote(ctx, w, remotePath, passThru, true)
+}
+
+func (a *Client) copyFromRemote(
+	ctx context.Context,
+	w io.Writer,
+	remotePath string,
+	passThru PassThru,
+	preserveFileTimes bool,
+) (*FileInfos, error) {
 	session, err := a.sshClient.NewSession()
 	if err != nil {
-		return fmt.Errorf("Error creating ssh session in copy from remote: %v", err)
+		return nil, fmt.Errorf("Error creating ssh session in copy from remote: %v", err)
 	}
 	defer session.Close()
 
 	wg := sync.WaitGroup{}
 	errCh := make(chan error, 4)
+	var fileInfos *FileInfos
 
 	wg.Add(1)
 	go func() {
@@ -349,7 +373,11 @@ func (a *Client) CopyFromRemotePassThru(
 		}
 		defer in.Close()
 
-		err = session.Start(fmt.Sprintf("%s -f %q", a.RemoteBinary, remotePath))
+		if preserveFileTimes {
+			err = session.Start(fmt.Sprintf("%s -pf %q", a.RemoteBinary, remotePath))
+		} else {
+			err = session.Start(fmt.Sprintf("%s -f %q", a.RemoteBinary, remotePath))
+		}
 		if err != nil {
 			errCh <- err
 			return
@@ -367,6 +395,8 @@ func (a *Client) CopyFromRemotePassThru(
 			return
 		}
 
+		fileInfos = fileInfo
+
 		err = Ack(in)
 		if err != nil {
 			errCh <- err
@@ -403,11 +433,12 @@ func (a *Client) CopyFromRemotePassThru(
 	}
 
 	if err := wait(&wg, ctx); err != nil {
-		return err
+		return nil, err
 	}
+
 	finalErr := <-errCh
 	close(errCh)
-	return finalErr
+	return fileInfos, finalErr
 }
 
 func (a *Client) Close() {

configurer.go

@@ -78,6 +78,6 @@ func (c *ClientConfigurer) Create() Client {
 		Timeout:      c.timeout,
 		RemoteBinary: c.remoteBinary,
 		sshClient:    c.sshClient,
-                closeHandler: EmptyHandler{},
+		closeHandler: EmptyHandler{},
 	}
 }

protocol.go

@@ -68,20 +68,19 @@ func ParseResponse(reader io.Reader, writer io.Writer) (*FileInfos, error) {
 				return nil, err
 			}
 
-			message, err = bufferedReader.ReadString('\n')
-			if err == io.EOF {
+			// A custom ssh server can send both time, permissions and size information at once
+			// without needing an Ack response. Example: wish from charmbracelet while using their default scp implementation
+			// If the buffer is empty, then it's likely the default implementation for ssh, so send Ack
+			if bufferedReader.Buffered() == 0 {
 				err = Ack(writer)
 				if err != nil {
 					return fileInfos, err
 				}
-				message, err = bufferedReader.ReadString('\n')
-
-				if err != nil {
-					return fileInfos, err
-				}
 			}
 
-			if err != nil && err != io.EOF {
+			message, err = bufferedReader.ReadString('\n')
+
+			if err != nil {
 				return fileInfos, err
 			}
 
@@ -102,7 +101,7 @@ func ParseResponse(reader io.Reader, writer io.Writer) (*FileInfos, error) {
 type FileInfos struct {
 	Message     string
 	Filename    string
-	Permissions string
+	Permissions uint32
 	Size        int64
 	Atime       int64
 	Mtime       int64
@@ -119,7 +118,7 @@ func (fileInfos *FileInfos) Update(new *FileInfos) {
 	if new.Filename != "" {
 		fileInfos.Filename = new.Filename
 	}
-	if new.Permissions != "" {
+	if new.Permissions != 0 {
 		fileInfos.Permissions = new.Permissions
 	}
 	if new.Size != 0 {
@@ -140,14 +139,19 @@ func ParseFileInfos(message string, fileInfos *FileInfos) error {
 		return errors.New("unable to parse Chmod protocol")
 	}
 
+	permissions, err := strconv.ParseUint(parts[0][1:], 0, 32)
+	if err != nil {
+		return err
+	}
+
 	size, err := strconv.Atoi(parts[1])
 	if err != nil {
 		return err
 	}
 
 	fileInfos.Update(&FileInfos{
 		Filename:    parts[2],
-		Permissions: parts[0],
+		Permissions: uint32(permissions),
 		Size:        int64(size),
 	})
 
@@ -164,11 +168,18 @@ func ParseFileTime(
 		return errors.New("unable to parse Time protocol")
 	}
 
-	aTime, err := strconv.Atoi(string(parts[0][0:10]))
+	if len(parts[0]) != 10 {
+		return errors.New("length of ATime is not 10")
+	}
+	mTime, err := strconv.Atoi(parts[0][0:10])
 	if err != nil {
 		return errors.New("unable to parse ATime component of message")
 	}
-	mTime, err := strconv.Atoi(string(parts[2][0:10]))
+
+	if len(parts[2]) != 10 {
+		return errors.New("length of MTime is not 10")
+	}
+	aTime, err := strconv.Atoi(parts[2][0:10])
 	if err != nil {
 		return errors.New("unable to parse MTime component of message")
 	}

tests/basic_test.go

@@ -3,6 +3,7 @@ package scp
 import (
 	"context"
 	"fmt"
+	"io/fs"
 	"os"
 	"strings"
 	"testing"
@@ -207,7 +208,35 @@ func TestDownloadFile(t *testing.T) {
 	client := establishConnection(t)
 	defer client.Close()
 
-	// Open a file we can transfer to the remote container.
+	// Create a local file to write to.
+	f, err := os.OpenFile("./tmp/output.txt", os.O_RDWR|os.O_CREATE, 0777)
+	if err != nil {
+		t.Errorf("Couldn't open the output file")
+	}
+	defer f.Close()
+
+	// Use a file name with exotic characters and spaces in them.
+	// If this test works for this, simpler files should not be a problem.
+	err = client.CopyFromRemote(context.Background(), f, "/input/Exöt1ç download file.txt.txt")
+	if err != nil {
+		t.Errorf("Copy failed from remote: %s", err.Error())
+	}
+
+	content, err := os.ReadFile("./tmp/output.txt")
+	if err != nil {
+		t.Errorf("Result file could not be read: %s", err)
+	}
+
+	text := string(content)
+	expected := "It works for download!\n"
+	if strings.Compare(text, expected) != 0 {
+		t.Errorf("Got different text than expected, expected %q got, %q", expected, text)
+	}
+}
+
+func TestDownloadFileInfo(t *testing.T) {
+	client := establishConnection(t)
+	defer client.Close()
 	f, _ := os.Open("./data/input.txt")
 	defer f.Close()
 
@@ -220,7 +249,12 @@ func TestDownloadFile(t *testing.T) {
 
 	// Use a file name with exotic characters and spaces in them.
 	// If this test works for this, simpler files should not be a problem.
-	err = client.CopyFromRemote(context.Background(), f, "/input/Exöt1ç download file.txt.txt")
+	fileInfos, err := client.CopyFromRemoteFileInfos(
+		context.Background(),
+		f,
+		"/input/Exöt1ç download file.txt.txt",
+		nil,
+	)
 	if err != nil {
 		t.Errorf("Copy failed from remote: %s", err.Error())
 	}
@@ -235,6 +269,31 @@ func TestDownloadFile(t *testing.T) {
 	if strings.Compare(text, expected) != 0 {
 		t.Errorf("Got different text than expected, expected %q got, %q", expected, text)
 	}
+
+	fileStat, err := os.Stat("./data/Exöt1ç download file.txt.txt")
+	if err != nil {
+		t.Errorf("Result file could not be read: %s", err)
+	}
+
+	if fileInfos.Size != fileStat.Size() {
+		t.Errorf("File size does not match")
+	}
+
+	if fs.FileMode(fileInfos.Permissions) == fs.FileMode(0777) {
+		t.Errorf(
+			"File permissions don't match %s vs %s",
+			fs.FileMode(fileInfos.Permissions),
+			fileStat.Mode().Perm(),
+		)
+	}
+
+	if fileInfos.Mtime != fileStat.ModTime().Unix() {
+		t.Errorf(
+			"File modification time does not match %d vs %d",
+			fileInfos.Mtime,
+			fileStat.ModTime().Unix(),
+		)
+	}
 }
 
 // TestTimeoutDownload tests that a timeout error is produced if the file is not copied in the given