File Transfer using TCP Socket in Python
Last Updated :
24 Apr, 2025
In this article, we implement a well-known Protocol in Computer Networks called File Transfer Protocol (FTP) using Python. We use the TCP Socket for this, i.e. a connection-oriented socket. FTP (File Transfer Protocol) is a network protocol for transmitting files between computers over Transmission Control Protocol/Internet Protocol (TCP/IP) connections. FTP is commonly used to transfer files behind the scenes for other applications, such as banking services.
Prerequisites: Socket-Programming in Python
File Structure
TCP-SERVER.py: Server-Side Implementation
We start by importing the socket library and making a simple socket. AF_INET refers to the address-family ipv4. The SOCK_STREAM means connection-oriented TCP protocol. After this, we bind the host address and port number to the server.
The user enters the maximum number of client connections required. On the basis of the input, we determine the size of an array storing clients called Connections. The server then keeps listening for client connections and if found adds them to the Connections array. It does this until the Connections array reaches its maximum limit. Then, for every connection, processing starts,
- Data is received and then decoded.
- If data is not null, the server creates a file with the name “Output<a unique number>.txt” and writes it into it.
- This is continued until all data is written into the file
- The above happens for all clients and then connections are closed. Hence, we are able to receive a new file at the server’s end with the exact same data.
Python3
import socket
if __name__ == '__main__':
host = '127.0.0.1'
port = 8080
totalclient = int(input('Enter number of clients: '))
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind((host, port))
sock.listen(totalclient)
connections = []
print('Initiating clients')
for i in range(totalclient):
conn = sock.accept()
connections.append(conn)
print('Connected with client', i+1)
fileno = 0
idx = 0
for conn in connections:
idx += 1
data = conn[0].recv(1024).decode()
if not data:
continue
filename = 'output'+str(fileno)+'.txt'
fileno = fileno+1
fo = open(filename, "w")
while data:
if not data:
break
else:
fo.write(data)
data = conn[0].recv(1024).decode()
print()
print('Receiving file from client', idx)
print()
print('Received successfully! New filename is:', filename)
fo.close()
for conn in connections:
conn[0].close()
|
TCP-CLIENT.py: Client-side Implementation
We first create a socket for a client and connect it to the server using the tuple containing the host address and port number. Then, the User enters the file name it wants to send to the server. After this, using the open() function of Python, the data of the file is read. Data is read line-by-line and then encoded into binary and sent to the server using socket.send(). When sending data is finished, the file is closed. It keeps on asking for a filename from the user until the client connection is terminated.
Python3
import socket
if __name__ == '__main__':
host = '127.0.0.1'
port = 8080
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
while True:
filename = input('Input filename you want to send: ')
try:
fi = open(filename, "r")
data = fi.read()
if not data:
break
while data:
sock.send(str(data).encode())
data = fi.read()
fi.close()
except IOError:
print('You entered an invalid filename!\
Please enter a valid name')
|
Output:
We first run the server using the command.
python tcp-server.py
Server Side Output
After this, we specify the maximum number of client connections possible ( say 2).
- Clients’ connections are initialized, i.e., the Connections array is generated with size 2 to store clients.
- After this, we create a new terminal and run our client using the command.
python tcp-client.py
The maximum number of tabs where we can run the command in the terminal will be 2. As we are initializing our client with this. So we create two clients Client 1 and Client 2.
Client Side Output
Once the client is run, we see an output “Connected with client 1” on the server side, indicating the connection is completed successfully with the first client. Same for the second client also.
After this, on the client side, we give the file name we want to send. Here file1.txt is sent by both clients. The content of file1.txt is shown below:
File sent to the server
Note that on the client side, we keep on showing the prompt: “Input filename you want to send:” so that a client can send multiple files. Once the connection with the client is disconnected, using “Control+C” in the terminal, a new file with the name Output<a number>.txt is generated on the server side with the same content, and the connection is closed. Here, the Client 1 file is stored as Output0.txt, and the Client 2 file is stored as Ouput1.txt.
File Received from Client 1
File Received from Client 2
Video for Reference
Similar Reads
Read JSON file using Python
The full form of JSON is JavaScript Object Notation. It means that a script (executable) file which is made of text in a programming language, is used to store and transfer the data. Python supports JSON through a built-in package called JSON. To use this feature, we import the JSON package in Pytho
4 min read
Writing to file in Python
Writing to a file in Python means saving data generated by your program into a file on your system. This article will cover the how to write to files in Python in detail. Creating a FileCreating a file is the first step before writing data to it. In Python, we can create a file using the following t
4 min read
Threaded Port Scanner using Sockets in Python
Port scanning can be really slow yet, in most cases, is not process intensive. Thus, we can use threading to improve our speed. There can be thousands of possible ports. If it takes 5-15 seconds per port to scan, then we might have a long wait ahead of us without the use of threading. Threading Thre
2 min read
Read File As String in Python
Python provides several ways to read the contents of a file as a string, allowing developers to handle text data with ease. In this article, we will explore four different approaches to achieve this task. Each approach has its advantages and uses cases, so let's delve into them one by one. Read File
3 min read
Port Scanner using Python
Prerequisites: Socket Programming in Python This article is just to provide a sample code to generate a Port Scanner. This Port Scanner will work for both the Web Applications as well as remote Host. This tool has been created to provide the basic functionality of a Port Scanner. The general concept
2 min read
File Sharing App using Python
Computer Networks is an important topic and to understand the concepts, practical application of the concepts is needed. In this particular article, we will see how to make a simple file-sharing app using Python. An HTTP Web Server is software that understands URLs (web address) and HTTP (the protoc
4 min read
How to Build a WiFi Scanner in Python using Scapy?
In this article, we are going to build a WiFi Scanner in Python using Scapy. WiFi Scanning or Network scanning refers to the scanning of the whole network to which we are connected and try to find out what are all the clients connected to our network. We can identify each client using their IP and M
3 min read
How To Send Files Using Python Built-In Http Server
Python's built-in HTTP server offers a straightforward way to share files over a local network or the internet without the need for complex setups. In this tutorial, we'll walk through the step-by-step process of using Python's built-in HTTP server to send files to clients. Setting Up the HTTP Serve
2 min read
Retrieving Cookies in Python
Retrieving cookies in Python can be done by the use of the Requests library. Requests library is one of the integral part of Python for making HTTP requests to a specified URL. The below codes show different approaches to do show: 1. By requesting a session: # import the requests library import requ
1 min read
Send Emails Using Python
By using Python, you can send emails which can be a valuable skill for automation, communication, and data-driven processes. In this article, we will explore how to send mail from Gmail using Python. How can you send Emails using Python?Python offers a library to send emails- "SMTP" Library. "smtpli
4 min read