Book Image

Hands-On Network Programming with C

By : Lewis Van Winkle
Book Image

Hands-On Network Programming with C

By: Lewis Van Winkle

Overview of this book

Network programming enables processes to communicate with each other over a computer network, but it is a complex task that requires programming with multiple libraries and protocols. With its support for third-party libraries and structured documentation, C is an ideal language to write network programs. Complete with step-by-step explanations of essential concepts and practical examples, this C network programming book begins with the fundamentals of Internet Protocol, TCP, and UDP. You’ll explore client-server and peer-to-peer models for information sharing and connectivity with remote computers. The book will also cover HTTP and HTTPS for communicating between your browser and website, and delve into hostname resolution with DNS, which is crucial to the functioning of the modern web. As you advance, you’ll gain insights into asynchronous socket programming and streams, and explore debugging and error handling. Finally, you’ll study network monitoring and implement security best practices. By the end of this book, you’ll have experience of working with client-server applications and be able to implement new network programs in C. The code in this book is compatible with the older C99 version as well as the latest C18 and C++17 standards. You’ll work with robust, reliable, and secure code that is portable across operating systems, including Winsock sockets for Windows and POSIX sockets for Linux and macOS.
Table of Contents (26 chapters)
Title Page
About Packt

The HTTP server

In this chapter, we are going to implement an HTTP web server that can serve static files from a local directory. HTTP is a text-based client-server protocol that uses the Transmission Control Protocol (TCP).

When implementing our HTTP server, we need to support multiple, simultaneous connections from many clients at once. Each received HTTP Request needs to be parsed, and our server needs to reply with the proper HTTP Response. This HTTP Response should include the requested file if possible.

Consider the HTTP transaction illustrated in the following diagram:

In the preceding diagram, the client is requesting /document.htm from the server. The server finds /document.htm and returns it to the client.

Our HTTP server is somewhat simplified, and we only need to look at the first line of the HTTP request. This first line is called the request line. Our server only supports GET type requests, so it needs to first check that the request line starts with GET. It then parses out the...