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client.go
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client.go
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// Copyright 2023 The Moov Authors
// Use of this source code is governed by an Apache License
// license that can be found in the LICENSE file.
package go_ftp
import (
"bufio"
"bytes"
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io"
"io/fs"
"os"
"path/filepath"
"strings"
"sync"
"time"
"github.com/jlaffaye/ftp"
)
type ClientConfig struct {
Hostname string
Username string
Password string
Timeout time.Duration
DisableEPSV bool
CAFile string
TLSConfig *tls.Config
}
type Client interface {
Ping() error
Close() error
Open(path string) (*File, error)
Reader(path string) (*File, error)
Delete(path string) error
UploadFile(path string, contents io.ReadCloser) error
ListFiles(dir string) ([]string, error)
Walk(dir string, fn fs.WalkDirFunc) error
}
func NewClient(cfg ClientConfig) (Client, error) {
cc := &client{
cfg: cfg,
}
// if err := rejectOutboundIPRange(cfg.SplitAllowedIPs(), cfg.FTP.Hostname); err != nil {
// return nil, fmt.Errorf("ftp: %s is not whitelisted: %v", cfg.FTP.Hostname, err)
// }
_, err := cc.connection() // initial connection
if err != nil {
return cc, fmt.Errorf("ftp connect: %v", err)
}
return cc, nil
}
type client struct {
conn *ftp.ServerConn
cfg ClientConfig
mu sync.Mutex // protects all read/write methods
}
// connection returns an ftp.ServerConn which is connected to the remote server.
// This function will attempt to establish a new connection if none exists already.
//
// connection must be called within a mutex lock as the underlying FTP client is not
// goroutine-safe.
func (cc *client) connection() (*ftp.ServerConn, error) {
if cc == nil {
return nil, errors.New("nil client or config")
}
if cc.conn != nil {
// Verify the connection works and f not drop through and reconnect
if err := cc.conn.NoOp(); err == nil {
return cc.conn, nil
} else {
// Our connection is having issues, so retry connecting
cc.conn.Quit()
}
}
// Setup our FTP connection
opts := []ftp.DialOption{
ftp.DialWithTimeout(cc.cfg.Timeout),
ftp.DialWithDisabledEPSV(cc.cfg.DisableEPSV),
}
tlsOpt, err := tlsDialOption(cc.cfg.TLSConfig, cc.cfg.CAFile)
if err != nil {
return nil, err
}
if tlsOpt != nil {
opts = append(opts, *tlsOpt)
}
// Make the first connection
conn, err := ftp.Dial(cc.cfg.Hostname, opts...)
if err != nil {
return nil, err
}
if err := conn.Login(cc.cfg.Username, cc.cfg.Password); err != nil {
return nil, err
}
cc.conn = conn
return cc.conn, nil
}
func tlsDialOption(conf *tls.Config, caFilePath string) (*ftp.DialOption, error) {
if caFilePath == "" {
return nil, nil
}
bs, err := os.ReadFile(caFilePath)
if err != nil {
return nil, fmt.Errorf("tlsDialOption: failed to read %s: %v", caFilePath, err)
}
pool, err := x509.SystemCertPool()
if pool == nil || err != nil {
pool = x509.NewCertPool()
}
ok := pool.AppendCertsFromPEM(bs)
if !ok {
return nil, fmt.Errorf("tlsDialOption: problem with AppendCertsFromPEM from %s", caFilePath)
}
if conf == nil {
conf = &tls.Config{
MinVersion: tls.VersionTLS12,
}
}
conf.RootCAs = pool
opt := ftp.DialWithTLS(conf)
return &opt, nil
}
func (cc *client) Ping() error {
if cc == nil {
return errors.New("nil FTP client")
}
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return err
}
return conn.NoOp()
}
func (cc *client) Close() error {
if cc == nil || cc.conn == nil {
return nil
}
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return err
}
return conn.Quit()
}
// Open will return the contents at path and consume the entire file contents.
// WARNING: This method can use a lot of memory by consuming the entire file into memory.
func (cc *client) Open(path string) (*File, error) {
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return nil, err
}
dir, filename := filepath.Split(path)
if dir != "" {
// Jump to previous directory after command is done
wd, err := conn.CurrentDir()
if err != nil {
return nil, err
}
defer func(previous string) {
// Return to our previous directory when initially called
if cleanupErr := conn.ChangeDir(previous); cleanupErr != nil {
err = fmt.Errorf("FTP: problem with readFiles: %w", cleanupErr)
}
}(wd)
// Move into directory to run the command
if err := conn.ChangeDir(dir); err != nil {
return nil, err
}
}
resp, err := conn.Retr(filename)
if err != nil {
return nil, fmt.Errorf("retrieving %s failed: %w", path, err)
}
data, err := readResponse(resp)
if err != nil {
return nil, fmt.Errorf("reading %s failed: %w", path, err)
}
return &File{
Filename: filepath.Base(path),
Contents: data,
}, nil
}
// Reader will open the file at path and provide a reader to access its contents.
// Callers need to close the returned Contents.
//
// Callers should be aware that network errors while reading can occur since contents
// are streamed from the FTP server. Having multiple open readers is not supported.
func (cc *client) Reader(path string) (*File, error) {
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return nil, err
}
file := &File{
Filename: filepath.Base(path),
}
dir, filename := filepath.Split(path)
if dir != "" {
// Jump to previous directory after command is done
wd, err := conn.CurrentDir()
if err != nil {
return nil, err
}
// On file Close move back to the directory we were previously in
file.cleanup = func() error {
err := conn.ChangeDir(wd)
if err != nil {
return fmt.Errorf("returning to %s failed: %w", wd, err)
}
return nil
}
// Move into directory to run the command
if err := conn.ChangeDir(dir); err != nil {
return nil, err
}
}
resp, err := conn.Retr(filename)
if err != nil {
return nil, fmt.Errorf("retrieving %s failed: %w", path, err)
}
file.Contents = resp
prev := file.cleanup
file.cleanup = func() error {
if resp != nil {
if err := resp.Close(); err != nil {
return fmt.Errorf("closing RETR %s response failed: %w", path, err)
}
}
return prev()
}
return file, nil
}
func (cc *client) Delete(path string) error {
cc.mu.Lock()
defer cc.mu.Unlock()
if path == "" || strings.HasSuffix(path, "/") {
return fmt.Errorf("FTP client: invalid path %v", path)
}
conn, err := cc.connection()
if err != nil {
return err
}
err = conn.Delete(path)
if err != nil && !strings.Contains(err.Error(), "no such file or directory") {
return err
}
return nil
}
// uploadFile saves the content of File at the given filename in the OutboundPath directory
//
// The File's contents will always be closed
func (cc *client) UploadFile(path string, contents io.ReadCloser) (err error) {
defer contents.Close()
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return err
}
dir, filename := filepath.Split(path)
if dir != "" {
// Jump to previous directory after command is done
wd, err := conn.CurrentDir()
if err != nil {
return err
}
defer func(previous string) {
// Return to our previous directory when initially called
if cleanupErr := conn.ChangeDir(previous); cleanupErr != nil {
err = fmt.Errorf("FTP: problem uploading %s: %w", filename, cleanupErr)
}
}(wd)
// Move into directory to run the command
if err := conn.ChangeDir(dir); err != nil {
return err
}
}
// Write file contents into path
// Take the base of f.Filename and our (out of band) OutboundPath to avoid accepting a write like '../../../../etc/passwd'.
return conn.Stor(filename, contents)
}
// ListFiles will return the paths of files within dir. Paths are returned as locations from dir,
// so if dir is an absolute path the returned paths will be.
//
// Paths are matched in case-insensitive comparisons, but results are returned exactly as they
// appear on the server.
func (c *client) ListFiles(dir string) ([]string, error) {
pattern := filepath.Clean(strings.TrimPrefix(dir, string(os.PathSeparator)))
switch {
case dir == "/":
pattern = "*"
case pattern == ".":
if dir == "" {
pattern = "*"
} else {
pattern = filepath.Join(dir, "*")
}
case pattern != "":
pattern += "/*"
}
var filenames []string
err := c.Walk(".", func(path string, d fs.DirEntry, err error) error {
if err != nil {
return err
}
if d.IsDir() {
return nil
}
// Check if the server's path matches what we're searching for in a case-insensitive comparison.
matches, err := filepath.Match(strings.ToLower(pattern), strings.ToLower(path))
if matches && err == nil {
// Return the path with exactly the case on the server.
idx := strings.Index(strings.ToLower(path), strings.ToLower(strings.TrimSuffix(pattern, "*")))
if idx > -1 {
path = path[idx:]
if strings.HasPrefix(dir, "/") && !strings.HasPrefix(path, "/") {
path = "/" + path
}
filenames = append(filenames, path)
} else {
// Fallback to Go logic of presenting the path
filenames = append(filenames, filepath.Join(dir, filepath.Base(path)))
}
}
return err
})
if err != nil {
return nil, fmt.Errorf("listing %s failed: %w", dir, err)
}
return filenames, nil
}
// Walk will traverse dir and call fs.WalkDirFunc on each entry.
//
// Follow the docs for fs.WalkDirFunc for details on traversal. Walk accepts fs.SkipDir to not process directories.
func (cc *client) Walk(dir string, fn fs.WalkDirFunc) error {
cc.mu.Lock()
defer cc.mu.Unlock()
conn, err := cc.connection()
if err != nil {
return err
}
if dir != "" && dir != "." {
// Jump to previous directory after command is done
wd, err := conn.CurrentDir()
if err != nil {
return err
}
defer func(previous string) {
// Return to our previous directory when initially called
if cleanupErr := conn.ChangeDir(previous); cleanupErr != nil {
err = fmt.Errorf("FTP: problem walking %s: %w", dir, cleanupErr)
}
}(wd)
// Move into directory to run the command
if err := conn.ChangeDir(dir); err != nil {
return err
}
}
// Setup a Walker for each file
walker := conn.Walk(dir)
for walker.Next() {
if err := walker.Err(); err != nil {
return err
}
entry := Entry{
fd: walker.Stat(),
}
if entry.fd == nil || entry.IsDir() {
continue
}
err = fn(walker.Path(), entry, walker.Err())
if err != nil {
if err == fs.SkipDir {
walker.SkipDir()
} else {
return fmt.Errorf("walking %s failed: %w", walker.Path(), err)
}
}
}
return nil
}
func readResponse(resp *ftp.Response) (io.ReadCloser, error) {
defer resp.Close()
var buf bytes.Buffer
n, err := io.Copy(&buf, bufio.NewReader(resp))
// If there was nothing downloaded and no error then assume it's a directory.
//
// The FTP client doesn't have a STAT command, so we can't quite ensure this
// was a directory.
//
// See https://github.com/moovfinancial/paygate/issues/494
if n == 0 && err == nil {
return io.NopCloser(&buf), nil
}
if err != nil {
return nil, fmt.Errorf("n=%d error=%v", n, err)
}
return io.NopCloser(&buf), nil
}