Network Prog CH 1: Introduction

Introduction to Network Programming

• This course introduces network programming using Python.
• The curriculum covers Python basics, data types, control flows, and object-oriented programming.
• Hands-on exercises are incorporated to enhance learning.
• Course goals include understanding networking software on different levels, network paradigms, using sockets for UDP and TCP connections, and implementing concurrent, inter-process, and synchronized applications.
• Recommended textbooks and additional reading materials are provided for further study.

Course Schedule (Tentative)

• Week 1: Setting up the development environment using VMware and introducing Python basics.
• Week 4: Exploring Python data types, including strings, lists, and dictionaries.
• Week 5: Learning about functions and classes in Python.
• Week 8: Working with files and classes in Python.
• Week 9: Understanding network addresses, TCP, and UDP sockets.
• Week 10: Multi-threading socket programming.
• Week 11: Introduction to application protocols (part 1).
• Week 12: Introduction to application protocols (part 2).

Course Assessment

• Lab Assignments (Weeks 6-8): 25% of the final grade.
• Midterm Exam (Week 8-9): 30% of the final grade, dates are subject to university guidelines.
• Final Exam (Weeks 15-16): 45% of the final grade, dates are subject to university guidelines.

What is Python?

• Python is an object-oriented, interpreted programming language.
• It's platform-independent and supports dynamic data types.
• Python prioritizes development time, is simple and easy to learn with an automatic memory management system.
• It's free and open-source.

Python Timeline

• Python was developed by Guido van Rossum during a holiday break in 1989.
• Its design took inspiration from the Monty Python's Flying Circus.
• The first public release was in 1991.
• Python moved to its own domain python.org in 1996/1997.
• Version 2.0 was released in 2000.
• Python Software Foundation was formed in 2001.
• Current version is 3.8.x.

Python Language Properties

• Everything in Python is an object.
• Python provides modules, classes, and functions.
• Exception handling is built-in.
• Dynamic typing and polymorphism are supported.
• Operator overloading is possible.
• Code blocks are defined via indentation.
• Static scoping is used for variable resolution.

Python Syntax Overview

• Python syntax is generally similar to that of C.
• Notably, it uses whitespace for code blocks, eliminating the need for curly braces.
• Python has specific keywords and a richer feature set.
• Type declarations are not needed.

Simple Data Types and Operators

• Python has several built-in data types, like integers, floating-point numbers, and complex numbers.
• Strings are also fundamental data types.
• Boolean type has two values: True and False.
• Operators (arithmetic, assignment, etc.) operate similarly to C, with some distinctions in semantics.

Strings and Formatting

• Python has powerful string manipulation capabilities, including concatenation, indexing, and slicing.
• print() offers formatting options using placeholders and special characters, such as escape sequences for newlines and tabs.

Python Escape Characters

• Escape sequences allow for special characters within strings.
• Characters are prefixed with a backslash.

Variables (in Python)

• Python variables don't require explicit declaration.
• They are created when assigned a value.
• Python is not strongly-typed; variable types are dynamically determined.
• Assignment manipulates references in some data types.

List Example - References/Mutability

• In Python, when you assign one list to another (e.g., b = a), it doesn't create a copy but merely creates a new reference to the original list. Any changes made to one list through that reference affect the original list.
• It is crucial in assignments to be careful about whether or not you are working with a copy.

Running Python Programs

• To run Python scripts, you can use the python command followed by the script name and .py extension.
• Alternatively, the -i flag allows interactive execution. To run a script you would type: $ python myprogram.py or $ python -i myprogram.py
• File naming conventions (and why you append .py)
  • myprogram.py – Python Script or module.
  • myprogram (no extension) – Executable script run from the command line, if you have created a proper script with a shebang (e.g. #!/usr/bin/env python3 ).

Helpful Vim Commands

• vim filename: Opens an existing file, or creates a new file.
• i: Enters insert mode to add text.
• :wq: Writes the file and leaves the editor.
• :q!: Leaves the editor without saving.
• :help: Accesses Vim's help system.

Python's Interactive Mode

• Starting Python in interactive mode (commonly just called 'the interpreter')
  • You can use the interpreter by typing python into the command line (depending on your operating system, this may vary)
  • Once inside you can type commands on a line and immediately see the result
  • Type ^D (control-D) to exit

Interactive Mode and Comments

• Use # for single line comments.
• Comments should be placed on the same line (line as text) as the code, for easier identification.
• >>> is the interpreter prompt.

Python Programming - Continued

• Python programming builds upon the foundation of these data types and operators, which aid in building control structures (like loops and conditionals) to create more sophisticated programs.
• The core data structures (like Lists and Dictionaries) and relevant functions (e.g., append, insert, count, etc.) can be used to build programs in a more targeted fashion.

This quiz assesses knowledge gained from the Introduction to Network Programming course using Python. It covers essential topics such as Python basics, data types, control flows, and the implementation of networking protocols including TCP and UDP. Practical exercises and concurrent programming concepts are also included in the curriculum.