Get rid of pysftp, it was pretty broken, now use paramiko directly

README.md

@@ -4,8 +4,11 @@ This is an access-control system implementation via contactless ISO 14443A cards
 and a PN53x-based reader. So you basically swipe your card, and if it's in
 database, the door unlocks.
 
+We still run this at this day (2023-09-16) because porting to Python 3 and SWIG is
+not that simple, especially the SWIG part.
+
 It's a bit old project, so requires python 2 (didn't have time for porting). At least currently
-(2010-05-28) still works on latest Raspberry 4 and Raspbian Buster.
+(2023-09-16) still works on latest Raspberry 4 and Raspbian Buster.
 
 Info about authorized users and their cards and keys is stored in sqlite database.
 
@@ -29,6 +32,9 @@ and panic trigger) or a cheap electromagnetic lock.
 * Yubikey Neo HMAC-SHA1 - most safe option, uncloneable
 * Mifare Desfire - Ed25519 signature of UID (currently no known clones available; although some features could be cloned,
   it's not enough for anyone to create such partial clones)
+  * working Mifare Desfire clones are nowhere to be seen in 2023, even though
+    the datasheet was leaked loooong time ago (adding encryption wouldn't be so
+    hard with `libfreefare`)
 
 Test code is also provided to get payment signature (cryptogram) from Visa and Mastercard, but it's not used.
 
@@ -63,7 +69,7 @@ You need just to run `make`. Additional dependencies:
 - [SWIG version 2](http://www.swig.org/) - to generate Python-C++ bindings, SWIG 3 is known to cause segfaults sometimes
 - [WiringPi2 pythonic binding](https://github.com/WiringPi/WiringPi2-Python) (for switching lock on Raspberry), install from pip, `pip install wiringpi`
 - [python-irc](https://pypi.python.org/pypi/irc) >= 16.0, use "pip install irc", the one in repos is old
-- [pysftp](https://pypi.org/project/pysftp/) - for uploading SpaceAPI-formatted status to some host
+- [paramiko](https://pypi.org/project/paramiko/) - for uploading SpaceAPI-formatted status to some host
   - optional runtime dependency, not needed unless you set SFTP SpaceAPI upload to true
 
 All dependencies can be installed on Ubuntu or Debian/Raspbian via:

brmdoor_nfc_daemon.py

@@ -382,21 +382,52 @@ class SpaceAPIUploader(object):
         :param isOpen - whether space is opened.
         :raises paramiko.ssh_exception.SSHException when upload fails (timeout, can't connect, host key mismatch...)
         """
-        import pysftp
+        import paramiko
         dirname, targetFname = os.path.split(self.config.sftpDestFile)
 
         spaceApiJson = json.load(file("spaceapi_template.json"))
         spaceApiJson["state"] = {"open": isOpen, "lastchange": time.time()}
 
         with tempfile.NamedTemporaryFile() as tf:
+            log_paramiko = logging.getLogger("paramiko")
+            if log_paramiko:
+                log_paramiko.setLevel(logging.WARNING)
+
             json.dump(spaceApiJson, tf, indent=4, ensure_ascii=True, encoding='utf-8')
             tf.flush()
             localFilename = tf.name
-            with pysftp.Connection(self.config.sftpHost, username=self.config.sftpUsername, port=self.config.sftpPort,
-                private_key=self.config.sftpKey) as sftp:
-                sftp.timeout = 15
-                with sftp.cd(dirname):
-                    sftp.put(localFilename, remotepath=targetFname)
+
+            pkey = None
+            ssh = None
+            sftp = None
+
+            for pkey_class in (paramiko.RSAKey, paramiko.DSSKey, paramiko.ECDSAKey, paramiko.Ed25519Key):
+                try:
+                    pkey = pkey_class.from_private_key_file(self.config.sftpKey)
+                    logging.debug("Loaded SSH key of type %s", pkey_class)
+                    break
+                except paramiko.ssh_exception.SSHException:
+                    pass
+
+            if pkey is None:
+                logging.error("Failed to load private SSH key", self.config.sftpKey)
+                raise paramiko.ssh_exception.SSHException("Can't read private SSH key")
+
+            try:
+                ssh = paramiko.SSHClient()
+                ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+                ssh.connect(self.config.sftpHost, username=self.config.sftpUsername, pkey=pkey, timeout=20)
+                sftp = ssh.open_sftp()
+
+                sftp.chdir(dirname)
+                sftp.put(localFilename, targetFname)
+
+            finally:
+                if sftp:
+                    sftp.close()
+
+                if ssh:
+                    ssh.close()
 
 
 class OpenSwitchThread(threading.Thread):