Protocols for Internet Communication

How do apps (web, mobile) communicate with each other in the internet?

• The TCP/IP model is a simplified set of standards and protocols for communication over the internet. This model is organized into 4 layers:
  • Network Access Layer
  • Internet Layer
  • Transport LAyer
  • Application Layer
• TCP is the transport-layer protocol over which other application-level protocols such as HTTP operate.
• HTTP is an application layer protocol and is the foundation for most web services. HTTP uses TCP in most cases as the transport protocol.

Project

This repository consists of 4 mini projects to learn about the foundation of TCP/IP and HTTP protocols:

• tcpserver/:
  • Utilization of TcpListener to listen to the incoming connection requests.
• tcpclient/:
  • Utilization of TcpStream to connect to localhost:3000.
• httpserver/:
  • Server $\rightarrow$ Listening for incoming TCP byte streams.
  • Router $\rightarrow$ Accepting HTTP requests and determining which handler to invoke.
  • Handler $\rightarrow$ Processing the HTTP requests and constructing HTTPS responses.
• http/:
  • HTTP Library $\rightarrow$ Interpreting the byte stream and converting it to HTTP request.

Setup Guide

Run the server always from protocols/directory.

cd protocols

To inspect the endpoints:

cargo run -p httpserver

The endpoints can be found in the following URLs:

• localhost:3000/
• localhost:3000/health
• localhost:3000/api/shipping/orders
• localhost:3000/invalid-path

To play with TCP server and client:

• First, start up the TCP server:

cargo run -p tcpserver

If it's successful, you will see the message "Running on port 3000"

• Then open another terminal, and execute the following:

cargo run -p tcpclient

In the TCP client, you will see the message "PING!" and when you go to the terminal that runs the TCP server, you will see "Connection established".

Summary

These are the implemented components in the protocols/ directory:

• The TCP/IP model is a simplified set of standards and protocols for communication over the internet. It is organized into four abstract layers: Network Access layer, Internet Layer, Transport Layer and the Application layer. TCP is the transport-layer protocol over which other application-level protocols such as HTTP operate. We built a server and client that exchanged data using the TCP protocol.
• TCP is also a stream-oriented protocol where data is exchanged as a continuous stream of bytes.
• We built a basic TCP server and client using the Rust standard library. TCP does not understand the semantics of messages such as HTTP. Our TCP client and server simply exchanged a stream of bytes without any understanding of the semantics of data transmitted.
• HTTP is an application layer protocol and is the foundation for most web services. HTTP uses TCP in most cases as the transport protocol.
• We built an HTTP library to parse incoming HTTP requests and construct HTTP responses. The HTTP requests and responses were modeled using Rust structs and enums.
• We built an HTTP server that serves two types of content - static web pages (with associated files such as stylesheets), and json data.
• Our web server can accept requests and send responses to standard HTTP clients such as browsers and curl tool.
• We added additional behaviour to our custom structs by implementing several traits. Some of them were auto-derived using Rust annotations, and others were hand-coded. We also made use of lifetime annotations to specify lifetimes of references within structs.

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Reference

I learn the implementation of TCP and HTTP protocols in Rust mostly from this amazing book (click on the link to buy one):

Eshwarla, P. (2023). Rust Servers, Services, and Apps (Early Access). Manning.

Disclaimer: I'm not in any way paid to suggest the above book. It is just an amazing book!

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