Made encoding keyword backward compatible

[richbon75]

The encoding parameter for ftplib.FTP was added in Python 3.9.

The update to add the encoding parameter broke backward compatibility with versions earlier than 3.9 (they raise an unexpected keyword error).

This pull request modifies the code so that if the encoding parameter is not supported, it fails back to a version of the FTP constructor without the encoding parameter.

[mristin]

Please see the suggested change.

[mristin]

Just before I squash and merge: @richbon75 did you test locally on your machine that it works as expected?

[richbon75]

Yup. Seems to be working as expected.

[mristin]

@richbon75 I just realized it might be very confusing for the user if s/he supplies the encoding parameter which is then ignored. I made yet another small suggestion.

[mristin]

A minor change slipped my attention -- please apologize the inconvenience; could you have another look?

[mristin]

(Unfortunately GitHub does not let me comment on unchanged lines. This comment refers to line 77.)

I only now realized that the user might be confused if the encoding parameter is simply ignored on older versions of Python.

What do you think about this additional change:

    def __init__(self,
             hostname: str,
             port: int,
             user: str,
             password: str,
             max_reconnects: int = 10,
             timeout: int = 10,
             FTP=ftplib.FTP,
             encoding: str = 'utf-8') -> None:
        # pylint: disable=too-many-arguments
        self.access = Access()
        self.access.hostname = hostname
        self.access.port = port
        self.access.user = user
        self.access.password = password
        self.connection = None  # type: Optional[ftplib.FTP]
        self.last_pwd = None  # type: Optional[str]
        self.encoding = encoding
        self.max_reconnects = max_reconnects
        self.timeout = timeout
        self.FTP = FTP  # pylint: disable=invalid-name
else:
    def __init__(self,
             hostname: str,
             port: int,
             user: str,
             password: str,
             max_reconnects: int = 10,
             timeout: int = 10,
             FTP=ftplib.FTP,
             encoding: str = 'utf-8') -> None:
        # pylint: disable=too-many-arguments
        self.access = Access()
        self.access.hostname = hostname
        self.access.port = port
        self.access.user = user
        self.access.password = password
        self.connection = None  # type: Optional[ftplib.FTP]
        self.last_pwd = None  # type: Optional[str]
        
        # No ``encoding `` is supported 
        # for this version of Python.
        
        self.max_reconnects = max_reconnects
        self.timeout = timeout
        self.FTP = FTP  # pylint: disable=invalid-name

[richbon75]

I didn't quite understand your intention in your code snippet, but I understood your suggestion that we not silently ignore a value provided for the encoding argument.

How about this latest update? It only raises an error IF a value is supplied for the encoding argument and the version < 3.9. If no argument is provided, the self.encoding attribute is never set. If the self.encoding attribute is not set, it is not passed to the call to self.FTP( ). This allows ftplib.FTP() to be responsible for setting the default value of encoding, and reconnecting-ftp doesn't have to provide a default at all.

[richbon75]

No longer providing a default for encoding. If the user doesn't provide one, an explicit value is no longer sent, allowing ftplib.FTP to supply it's own default of 'utf-8' in versions 3.9+

[mristin]

Thanks, this is a much better solution than mine!