Python is a widely-used programming language. It was created in 1991. This language was designed to improve code readability and syntax. There are two versions of Python: Python 2 and Python 3.
In this article, we will learn about the essence of network programming using Python. For learning Python network programming, one must know about the following topics:
- Data encoding
- High-level client modules
- HTTP and web programming
- Programming using sockets
- Basic networking terms
Reasons for the Popularity of Python
- We can express concepts easily and in fewer lines of code.
- Python supports multiple libraries and functions.
- It emphasizes code readability and syntax.
- Python can be used to make games, data analysis, create GUI’s, and websites.
Features of Python
- Easy to learn: It is easy to learn due to simple syntax and functioning.
- Interactive mode available: This language also has support for an interactive mode that allows interactive testing.
- Easy to read: Python’s written codes are easy to read.
- Easy to maintain: Python written codes are easy to maintain.
- Portable: Python has the same interface on all platforms. It can be run on a wide variety of hardware sources.
- GUI programming: Python supports many GUI applications that are created and can be ported to libraries and system calls.
Network Services in Python
There are two levels of network services in Python. These are:
- High-level access
- Low-level access
In the low-level access, we can use and access the socket support for the operating systems by using Python libraries. Programmers can also implement connection-less and connection-oriented protocols for performing network programming.
Programmers can access the application-level network protocols by using high-level access services. The standard library of Python has full support for protocols, encoding, and networking concepts.
What is a Socket?
A socket is defined as an end-point in the flow of communication between any two programs or channels. The sockets are created by using a set of requests in programming, also called socket API (Application Programming Interface).
These sockets use various protocols for determining a connection for port-to-port communication. The main uses of protocols are:
- IP addressing
- FTP (File transfer protocol)
- Domain Name servers
Domain: It is a family of protocols that are used as the mechanism for transportation.
Type: It is the type of communication between two endpoints.
Protocol: It is used to identify a variant.
Port: It is a medium through which the server listens to the clients.
A program for socket
Python has a socket method that sets up different sockets virtually. The syntax for the same is as follows –
s= socket.socket (socketFamily, type_of_the_socket, protocol=value)
socketFamily: It is either AF_UNIX or AF_INET.
type_of_the_socket: It is either SOCK_STREAM or SOCK_DGRAM.
Protocol: It is usually left out and defaulting to 0.
Methods to manage the connections:
- listen(): This method is used to establish and start TCP listeners.
- bind(): This method is used to bind-address to the socket.
- connect(): It is used to make a connection with the TCP server.
- accept(): It is used to make a TCP client connection.
- recv(): This method is used to receive messages.
- close(): It is used to close a socket.
- sendto(): This method is used to send UDP messages.
- Send(): This method is used to send messages.
Why Python for Network Programming?
Python is a powerful language, and there are many reasons for using Python for network programming. It has an easy syntax and is simple to implement amongst its counterparts. You can do almost everything with the Python programming language. It is powerful enough to make websites and provide a backbone to the Google search engine. It also supports third-party libraries.
Sending messages back and forward by using the basic protocols is straightforward. It also shows that programming plays a vital role in client and server functioning. Python executes synchronously. It provides a socket class so that programmers can easily use the socket objects in their codes. You can implement it by importing the socket library in your program. Python also has classes that make use of low-level socket functions. Therefore, Python is the perfect choice for network programming.
Let us quickly discuss the basic terms of networking:
Internet protocol: Internet protocol is a set of rules and procedures to govern the flow of data. It has two significant protocols:
User Datagram Protocol (UDP)
The User Datagram Protocol is a connectionless protocol. Some properties of UDP are:
- Unreliable: Whenever a User Datagram Protocol message is sent, we don’t have a way to know whether it has reached its destination or not. In the User Datagram protocol, there is no way of acknowledgment.
- Not ordered: We cannot predict the order of messages in which they arrive.
Transmission control protocol
TCP uses the concept of a handshake. In simple words, it is a way to ensure that the connection has been established between hosts, and now the data transfer can be started. TCP protocol requires us to build a network in the first place. Some properties of Transmission Control Protocol are:
- Reliable: Transmission Control Protocol manages the acknowledgment and timeout of the message. It makes several attempts to deliver the messages. The server also requests the lost parts again to get the lost messages.
- Heavy-weight: Transmission Control Protocol has three packets to set up a connection for the socket. These packets are:
Python Internet Modules
|Protocol Name||The Function of the protocol||Port No.||Python Module associated|
|Gopher||Transfer of documents||70||Gopherlib, urllib|
|Telnet||Used for Command line||23||telnetlib|
|IMAP4||Used for fetching emails||143||impalib|
|POP3||Used for fetching emails||110||poplib|
|SMTP||Used for sending emails||25||smtlib|
|FTP||Used for file transfers||20||Ftblib, urllib|
|HTTP||Used for web pages||80||Httplib, urllib|
These are the fundamental properties of Python as a networking language. Thus, Python is a general-purpose programming language. It is object-oriented and interactive. It uses English keywords frequently, which makes it easy to understand.
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