sftp_tools.py

# -*- coding: utf-8 -*-
"""
Created on Fri Sep 16 15:56:23 2022

@author: hendrik_gt
"""

# -*- coding: utf-8 -*-
# Copyright notice
#   --------------------------------------------------------------------
#   Copyright (C) 2022 Deltares
#       Gerrit Hendriksen
#       gerrit.hendriksen@deltares.nl   
#       Nathalie Dees (nathalie.dees@deltares.nl)
#
#   This library is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This library is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this library.  If not, see <http://www.gnu.org/licenses/>.
#   --------------------------------------------------------------------
#
# This tool is part of <a href="http://www.OpenEarth.eu">OpenEarthTools</a>.
# OpenEarthTools is an online collaboration to share and manage data and
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# setup connection with sftp box
import pysftp
import configparser
from urllib.parse import urlparse
import os
import shutil

#load local procedures to write to db
from ext_loaddataintodatamodel import metadata_location, timeseries_todb, update_location
from ts_helpders import establishconnection, read_config, loadfilesource,location,sparameter,sserieskey,sflag,dateto_integer,convertlttodate, stimestep


class Sftp:
    def __init__(self, hostname, username, password, port=22):
        """Constructor Method"""
        # Set connection object to None (initial value)
        self.connection = None
        self.hostname = hostname
        self.username = username
        self.password = password
        self.port = int(port)

    def connect(self):
        """Connects to the sftp server and returns the sftp connection object"""
        cnopts = pysftp.CnOpts()
        cnopts.hostkeys = None
        try:
            # Get the sftp connection object
            self.connection = pysftp.Connection(
                host=self.hostname,
                username=self.username,
                password=self.password,
                port=self.port, cnopts = cnopts
            )
        except Exception as err:
            raise Exception(err)
        finally:
            print(f"Connected to {self.hostname} as {self.username}.")


    def disconnect(self):
        """Closes the sftp connection"""
        self.connection.close()
        print(f"Disconnected from host {self.hostname}")
        
    def listdir(self, remote_path):
        """lists all the files and directories in the specified path and returns them"""
        for obj in self.connection.listdir(remote_path):
            yield obj

    def listdir_attr(self, remote_path):
        """lists all the files and directories (with their attributes) in the specified path and returns them"""
        for attr in self.connection.listdir_attr(remote_path):
            yield attr        
            
    def download(self, remote_path, target_local_path):
        """
        Downloads the file from remote sftp server to local.
        Also, by default extracts the file to the specified target_local_path
        """

        try:
            print(
                f"downloading from {self.hostname} as {self.username} [(remote path : {remote_path});(local path: {target_local_path})]"
            )

            # Create the target directory if it does not exist
            path, _ = os.path.split(target_local_path)
            if not os.path.isdir(path):
                try:
                    os.makedirs(path)
                except Exception as err:
                    raise Exception(err)

            # Download from remote sftp server to local
            self.connection.get(remote_path, target_local_path)
            print("download completed")

        except Exception as err:
            raise Exception(err)   

    def remove_file(self,file):
        "removes file from ftp server according to sftp docs"
        self.connection.remove(file)