FTP server communication with ftplib python module

ftp_python

Skill - FTP server communication with ftplib python module

In this post we try to learn how to use ftplib python module to interact with FTP server
ftplib is an inbuilt python module that can be used for FTP server interactions like upload files, download files, read list of file names etc
If you want to setup a local FTP server, you can read my blog post here

Connect to an FTP server

The following parameters are required to establish a connection to an FTP server

FTP server host address (like “localhost” or “192.87.34.1” or “myftp.abcd.com”)
FTP server port (usually is 21)
username
password

Without SSL

import ftplib

# connection parameters
ftpHost = 'localhost'
ftpPort = 21
ftpUname = 'uname'
ftpPass = 'pass'

# create an FTP client instance, use the timeout(seconds) parameter for slow connections only
ftp = ftplib.FTP(timeout=30)

# connect to the FTP server
ftp.connect(ftpHost, ftpPort)

# login to the FTP server
ftp.login(ftpUname, ftpPass)

# do something with the ftp client like upload, download etc

# send QUIT command to the FTP server and close the connection
ftp.quit()
print("execution complete...")

With SSL

While connecting to FTP server using SSL, use FTP_TLS instead of FTP function
Also we need to call ftp.prot_p() to secure the connection after logging in

import ftplib

# connection parameters
ftpHost = 'localhost'
ftpPort = 21
ftpUname = 'uname'
ftpPass = 'pass'

# create an FTP client instance, use the timeout(seconds) parameter for slow connections only
ftp = ftplib.FTP_TLS(timeout=30)

# connect to the FTP server
ftp.connect(ftpHost, ftpPort)

# login to the FTP server
ftp.login(ftpUname, ftpPass)

# setup secure data connection
ftp.prot_p()

# do something with the ftp client like upload, download etc

# send QUIT command to the FTP server and close the connection
ftp.quit()
print("execution complete...")

Change working directory using ‘cwd’

## ... code to connect to ftp server

# change working directory to a different folder
ftp.cwd("folder1/abcd")

# ... do something

Get the list of filenames in a folder using ‘nlst’

In the below python script, we have created a function that fetches the list of filenames from the desired FTP server directory.

import ftplib

def getFtpFilenames(ftpHost, ftpPort, ftpUname, ftpPass, remoteWorkingDirectory):
    # create an FTP client instance, use the timeout(seconds) parameter for slow connections only
    ftp = ftplib.FTP(timeout=30)
    
    # connect to the FTP server
    ftp.connect(ftpHost, ftpPort)
    
    # login to the FTP server
    ftp.login(ftpUname, ftpPass)

    # change current working directory if specified
    if not (remoteWorkingDirectory == None or remoteWorkingDirectory.strip() == ""):
        _ = ftp.cwd(remoteWorkingDirectory)
    
    # initialize the filenames as an empty list
    fnames = []
    
    try:
        # use nlst function to get the list of filenames
        fnames = ftp.nlst()
    except ftplib.error_perm as resp:
        if str(resp) == "550 No files found":
            fnames = []
        else:
            raise
    
    # send QUIT command to the FTP server and close the connection
    ftp.quit()

    # return the list of filenames
    return fnames

# connection parameters
ftpHost = 'localhost'
ftpPort = 21
ftpUname = 'uname'
ftpPass = 'pass'
fnames = getFtpFilenames(ftpHost, ftpPort, ftpUname, ftpPass, "folder1/abcd")
print(fnames)
print("execution complete...")

You can copy this function and directly use it in your projects

Upload files to FTP server directory using ‘storbinary’

In the below python script, we have created a function that uploads a local file into the desired FTP server directory.

import ftplib
import os

def uploadFileToFtp(localFilePath, ftpHost, ftpPort, ftpUname, ftpPass, remoteWorkingDirectory):
    # initialize the flag that specifies if upload is success
    isUploadSuccess: bool = False

    # extract the filename of local file from the file path
    _, targetFilename = os.path.split(localFilePath)

    # create an FTP client instance, use the timeout parameter for slow connections only
    ftp = ftplib.FTP(timeout=30)

    # connect to the FTP server
    ftp.connect(ftpHost, ftpPort)

    # login to the FTP server
    ftp.login(ftpUname, ftpPass)

    # change current working directory if specified
    if not (remoteWorkingDirectory == None or remoteWorkingDirectory.strip() == ""):
        _ = ftp.cwd(remoteWorkingDirectory)

    # Read file in binary mode
    with open(localFilePath, "rb") as file:
        # upload file to FTP server using storbinary, specify blocksize(bytes) only if higher upload chunksize is required
        retCode = ftp.storbinary(f"STOR {targetFilename}", file, blocksize=1024*1024)

    # send QUIT command to the FTP server and close the connection
    ftp.quit()

    # check if upload is success using the return code (retCode)
    if retCode.startswith('226'):
        isUploadSuccess = True

    # return the upload status
    return isUploadSuccess

# connection parameters
ftpHost = 'localhost'
ftpPort = 21
ftpUname = 'uname'
ftpPass = 'pass'
localFile = 'test.txt'
remoteFolder = "folder1/abcd"

# upload file
isUploadSuccess = uploadFileToFtp(localFile, ftpHost, ftpPort, ftpUname, ftpPass, remoteFolder)

print("upload status = {0}".format(isUploadSuccess))

This function can be copied and used directly in your projects
We can modify this function to for uploading multiple files into the FTP server using a for loop inside the function

Download files from FTP server directory using ‘retrbinary’

In the below python script, we have created a function that downloads files from FTP server into a local directory.

import ftplib
import os


def downloadFilesFromFtp(localfolderPath, targetFilenames, ftpHost, ftpPort, ftpUname, ftpPass, remoteWorkingDirectory):
    # initialize the flag that specifies if download is success
    isDownloadSuccess: bool = False

    # create an FTP client instance, use the timeout parameter for slow connections only
    ftp = ftplib.FTP(timeout=30)

    # connect to the FTP server
    ftp.connect(ftpHost, ftpPort)

    # login to the FTP server
    ftp.login(ftpUname, ftpPass)

    # change current working directory if specified
    if not (remoteWorkingDirectory == None or remoteWorkingDirectory.strip() == ""):
        _ = ftp.cwd(remoteWorkingDirectory)

    # iterate through each remote filename and download
    for fItr in range(len(targetFilenames)):
        targetFilename = targetFilenames[fItr]
        # derive the local file path by appending the local folder path with remote filename
        localFilePath = os.path.join(localfolderPath, targetFilename)
        print("downloading file {0}".format(targetFilename))
        # download FTP file using retrbinary function
        with open(localFilePath, "wb") as file:
            retCode = ftp.retrbinary("RETR " + targetFilename, file.write)

    # send QUIT command to the FTP server and close the connection
    ftp.quit()

    # check if download is success using the return code (retCode)
    if retCode.startswith('226'):
        isDownloadSuccess = True
    return isDownloadSuccess


# connection parameters
ftpHost = 'localhost'
ftpPort = 21
ftpUname = 'uname'
ftpPass = 'pass'
localFolderPath = ""
remoteFolder = "folder1/abcd"
remoteFilenames = ["rguj.docx"]

# run the function to download the files from FTP server
isDownloadSuccess = downloadFilesFromFtp(
    localFolderPath,remoteFilenames, ftpHost, ftpPort, ftpUname, ftpPass, remoteFolder)

print("download status = {0}".format(isDownloadSuccess))

This function can be copied and used directly in your projects
We can modify this function as per our requirements like specifying local filenames etc.

Other important FTP actions

All the important python ftp functions for directory listing, rename, delete file, delete folder, create folder, get the size of files etc. can be found at https://docs.python.org/3/library/ftplib.html#ftplib.FTP.dir

ftp.dir(argument[, …])
Produce a directory listing as returned by the LIST command, printing it to standard output. The optional argument is a directory to list (default is the current server directory). Multiple arguments can be used to pass non-standard options to the LIST command. If the last argument is a function, it is used as a callback function as for retrlines(); the default prints to sys.stdout. This method returns None.

ftp.rename(fromname, toname)
Rename file fromname on the server to toname.

ftp.delete(filename)
Remove the file named filename from the server. If successful, returns the text of the response, otherwise raises error_perm on permission errors or error_reply on other errors.

ftp.cwd(pathname)
Set the current directory on the server.

ftp.mkd(pathname)
Create a new directory on the server.

ftp.pwd()
Return the pathname of the current directory on the server.

ftp.rmd(dirname)
Remove the directory named dirname on the server.

ftp.size(filename)
Request the size of the file named filename on the server. On success, the size of the file is returned as an integer, otherwise None is returned. Note that the SIZE command is not standardized, but is supported by many common server implementations.

Video

Video for this post can be found here

References

Official ftplib documentation - https://docs.python.org/3/library/ftplib.html

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