support remote path from URL, make URL and arg not option

api.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	url_ "net/url"
 	"os"
+	"path/filepath"
 
 	"github.com/pkg/sftp"
 	"golang.org/x/crypto/ssh"
@@ -33,7 +34,7 @@ type result struct {
 }
 
 type sftpAPI struct {
-	url    url_.URL
+	url    *url_.URL
 	client *sftp.Client
 	cfg    ssh.ClientConfig
 	req    io.Reader
@@ -125,8 +126,16 @@ func (s sftpAPI) textCommands() <-chan command {
 	return ch
 }
 
+func (s sftpAPI) rempath(path string) string {
+	if !filepath.IsAbs(path) {
+		return filepath.Join(s.url.Path, path)
+	}
+	return path
+}
+
 // args: source, dest as abs paths
 func (s sftpAPI) doPut(source, dest string) error {
+	dest = s.rempath(dest)
 	fout, err := s.client.Create(dest)
 	if err != nil {
 		return errors.Wrapf(err, "can't create %s", dest)
@@ -148,6 +157,8 @@ func (s sftpAPI) doPut(source, dest string) error {
 
 // args: source, dest as abs paths
 func (s sftpAPI) doGet(source, dest string) error {
+	source = s.rempath(source)
+
 	fin, err := s.client.Open(source)
 	if err != nil {
 		return errors.Wrapf(err, "can't read %s", source)
@@ -177,6 +188,7 @@ type stat struct {
 func (s sftpAPI) doListdir(path string) ([]stat, error) {
 	stats := []stat{}
 
+	path = s.rempath(path)
 	infos, err := s.client.ReadDir(path)
 	if err != nil {
 		return stats, err
@@ -191,7 +203,7 @@ func (s sftpAPI) doListdir(path string) ([]stat, error) {
 
 // args: abspath
 func (s sftpAPI) doDelete(path string) error {
-	return s.client.Remove(path)
+	return s.client.Remove(s.rempath(path))
 }
 
 func (s *sftpAPI) ensureConnected() error {
@@ -287,32 +299,28 @@ func (s sftpAPI) close() {
 	}
 }
 
-func cleanURL(url string) (url_.URL, error) {
-	newURL := url_.URL{
-		Scheme: "sftp",
-	}
-
+// cleanURL takes an input url and makes sure it has a default user and port
+func cleanURL(url string) (*url_.URL, error) {
 	u, err := url_.Parse(url)
 	if len(url) == 0 || err != nil {
-		return newURL, err
+		return &url_.URL{}, err
+	}
+
+	if u.Scheme != "sftp" {
+		debug("URL does not have scheme sftp, ignoring")
 	}
-	newURL.Path = u.Path
 
 	username := u.User.Username()
 	if len(username) == 0 {
 		username = os.Getenv("USER")
 	}
-	newURL.User = url_.User(username)
+	u.User = url_.User(username)
 
-	host := u.Hostname()
-	if len(u.Port()) != 0 {
-		host += ":" + u.Port()
-	} else {
-		host += ":22"
+	if len(u.Port()) == 0 {
+		u.Host += ":22"
 	}
-	newURL.Host = host
 
-	return newURL, nil
+	return u, nil
 }
 
 func parseServerHostKey(fpath string) (ssh.PublicKey, error) {

main.go

@@ -34,10 +34,14 @@ func main() {
 	log.SetOutput(os.Stderr)
 
 	pflag.Usage = func() {
-		fmt.Fprintf(os.Stderr, `%s [options]
+		fmt.Fprintf(os.Stderr, `%s [options] <url>
 
 Mini in-process API to drive an SFTP connection.
 
+Arguments:
+
+    url: SFTP base url sftp://[<user>@]<hostname>[:port][<basepath>]
+
 Options:
 
 `, os.Args[0])
@@ -57,7 +61,6 @@ https://gitlab.ssec.wisc.edu/brucef/sftper
 			"you're super-duper sure you will have no strings with new lines. But, it sure is handy for testing.")
 		source = pflag.StringP("commands", "c", "-", "File where commands are read from.")
 		help   = pflag.Bool("help", false, "Print help and exit")
-		urlArg = pflag.String("url", "", "SFTP base url sftp://[<user>@]<hostname>[:port]. Any provided path will be ignored")
 		// pflag.BoolVar(&verbose, "verbose", false, "Verbose output")
 		pKey = pflag.StringP("pkey", "i", defaultPrivateKey(), "Path to PEM formatted private key.")
 		hKey = pflag.StringP("hkey", "h", "", "Path to PEM formatted host public key. If not "+
@@ -68,7 +71,7 @@ https://gitlab.ssec.wisc.edu/brucef/sftper
 
 	pflag.Parse()
 
-	if *help {
+	if *help || pflag.NArg() != 1 {
 		pflag.Usage()
 		os.Exit(2)
 	}
@@ -83,7 +86,7 @@ https://gitlab.ssec.wisc.edu/brucef/sftper
 		}
 	}
 
-	sftp, err := newSftpApi(*urlArg, *pKey, *hKey, input, os.Stdout)
+	sftp, err := newSftpApi(pflag.Arg(0), *pKey, *hKey, input, os.Stdout)
 	if err != nil {
 		info("could not initialize api: %s", err)
 		os.Exit(2)