Add initial SSH/SFTP framework for downloading directories/files

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "metainfo/vendor/github.com/anacrolix/torrent"]
+	path = metainfo/vendor/github.com/anacrolix/torrent
+	url = ssh://git@github.com/anacrolix/torrent.git

lib/easysftp/easysftp.go

@@ -0,0 +1,239 @@
+package easysftp
+
+import (
+	"errors"
+	"github.com/pkg/sftp"
+	"golang.org/x/crypto/ssh"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// ClientConfig maintains all of the configuration info to connect to a SSH host
+type ClientConfig struct {
+	Username string
+	Host     string
+	KeyPath  string
+	Password string
+	Timeout  time.Duration
+	FileMode os.FileMode
+}
+
+// Client communicates with the SFTP to download files/pathes
+type Client struct {
+	sshClient *ssh.Client
+	config    *ClientConfig
+}
+
+// Connect to a host with this given config
+func Connect(config *ClientConfig) (*Client, error) {
+	var auth []ssh.AuthMethod
+	if config.KeyPath != "" {
+		privKey, err := ioutil.ReadFile(config.KeyPath)
+		if err != nil {
+			return nil, err
+		}
+		signer, err := ssh.ParsePrivateKey(privKey)
+		if err != nil {
+			return nil, err
+		}
+
+		auth = append(auth, ssh.PublicKeys(signer))
+	}
+
+	if len(auth) == 0 {
+		if config.Password == "" {
+			return nil, errors.New("Missing password or key for SSH authentication")
+		}
+
+		auth = append(auth, ssh.Password(config.Password))
+	}
+
+	sshClient, err := ssh.Dial("tcp", config.Host, &ssh.ClientConfig{
+		User:    config.Username,
+		Auth:    auth,
+		Timeout: config.Timeout,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{
+		sshClient: sshClient,
+		config:    config,
+	}, nil
+}
+
+// Close the underlying SSH conection
+func (c *Client) Close() error {
+	return c.sshClient.Close()
+}
+
+func (c *Client) newSftpClient() (*sftp.Client, error) {
+	return sftp.NewClient(c.sshClient)
+}
+
+// Stat gets information for the given path
+func (c *Client) Stat(path string) (os.FileInfo, error) {
+	sftpClient, err := c.newSftpClient()
+	if err != nil {
+		return nil, err
+	}
+
+	defer sftpClient.Close()
+
+	return sftpClient.Stat(path)
+}
+
+// Lstat gets information for the given path, if it is a symbolic link, it will describe the symbolic link
+func (c *Client) Lstat(path string) (os.FileInfo, error) {
+	sftpClient, err := c.newSftpClient()
+	if err != nil {
+		return nil, err
+	}
+
+	defer sftpClient.Close()
+
+	return sftpClient.Lstat(path)
+}
+
+// Download a file from the given path to the output writer
+func (c *Client) Download(path string, output io.Writer) error {
+	sftpClient, err := c.newSftpClient()
+	if err != nil {
+		return err
+	}
+
+	defer sftpClient.Close()
+
+	info, err := sftpClient.Stat(path)
+	if err != nil {
+		return err
+	}
+
+	if info.IsDir() {
+		return errors.New("Unable to use easysftp.Client.Download for dir: " + path)
+	}
+
+	remote, err := sftpClient.Open(path)
+	if err != nil {
+		return err
+	}
+
+	defer remote.Close()
+
+	_, err = io.Copy(output, remote)
+	return err
+}
+
+// Mirror downloads an entire folder (recursively) or file underneath the given localParentPath
+func (c *Client) Mirror(path string, localParentPath string) error {
+	sftpClient, err := c.newSftpClient()
+	if err != nil {
+		return err
+	}
+
+	defer sftpClient.Close()
+
+	info, err := sftpClient.Stat(path)
+	if err != nil {
+		return err
+	}
+
+	// download the file
+	if !info.IsDir() {
+		sftpClient.Close()
+		localPath := filepath.Join(localParentPath, info.Name())
+		localInfo, err := os.Stat(localPath)
+		if os.IsExist(err) && localInfo.IsDir() {
+			err = os.RemoveAll(localPath)
+			if err != nil {
+				return err
+			}
+		}
+
+		file, err := os.OpenFile(
+			localPath,
+			os.O_RDWR|os.O_CREATE|os.O_TRUNC,
+			c.config.FileMode,
+		)
+		if err != nil {
+			return err
+		}
+
+		defer file.Close()
+
+		return c.Download(path, file)
+	}
+
+	// download the whole directory recursively
+	walker := sftpClient.Walk(path)
+	remoteParentPath := filepath.Dir(path)
+	for walker.Step() {
+		if err := walker.Err(); err != nil {
+			return err
+		}
+
+		info := walker.Stat()
+
+		relPath, err := filepath.Rel(remoteParentPath, walker.Path())
+		if err != nil {
+			return err
+		}
+
+		localPath := filepath.Join(localParentPath, relPath)
+
+		// if we have something at the download path delete it if it is a directory
+		// and the remote is a file and vice a versa
+		localInfo, err := os.Stat(localPath)
+		if os.IsExist(err) {
+			if localInfo.IsDir() {
+				if info.IsDir() {
+					continue
+				}
+
+				err = os.RemoveAll(localPath)
+				if err != nil {
+					return err
+				}
+			} else if info.IsDir() {
+				err = os.Remove(localPath)
+				if err != nil {
+					return err
+				}
+			}
+		}
+
+		if info.IsDir() {
+			err = os.MkdirAll(localPath, c.config.FileMode)
+			if err != nil {
+				return err
+			}
+
+			continue
+		}
+
+		remoteFile, err := sftpClient.Open(walker.Path())
+		if err != nil {
+			return err
+		}
+
+		localFile, err := os.OpenFile(localPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, c.config.FileMode)
+		if err != nil {
+			remoteFile.Close()
+			return err
+		}
+
+		_, err = io.Copy(localFile, remoteFile)
+		remoteFile.Close()
+		localFile.Close()
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

metainfo/metainfo.go

@@ -0,0 +1,17 @@
+package metainfo
+
+import (
+	"github.com/anacrolix/torrent/metainfo"
+	"io"
+	"strings"
+)
+
+// GetTorrentHashHexString Returns the torrent hash for the given reader
+func GetTorrentHashHexString(reader io.Reader) (string, error) {
+	info, err := metainfo.Load(reader)
+	if err != nil {
+		return "", err
+	}
+
+	return strings.ToUpper(info.Info.Hash.HexString()), nil
+}

metainfo/vendor/github.com/anacrolix/torrent

@@ -0,0 +1 @@
+Subproject commit dcfee93f96d231b5590f991313b5d9f925757f52