Foundations of Python Network Programming, Third Edition

This is the Chinese translation of the third edition of Foundations of Python Network Programming. All examples are written in Python 3. The book is aimed at developers who already have some Python background and want to understand network protocols in depth and build network applications with Python. It begins with the client/server model, first laying out the layered relationship between protocol stacks and libraries, the use of application-layer protocols, character encoding and decoding, IP addresses and routing, then moves on to UDP and TCP socket programming, covering practical details such as port numbers, binding to interfaces, timeouts and backoff, connection management, deadlock and half-open connections. It then covers socket names and DNS resolution, serialization of network data and handling of network errors, and TLS/SSL encrypted communication. On the server side, the book discusses multiprocess/multithreaded server architectures and the use of caching and message queues, and analyzes HTTP from both client and server perspectives, extending to security topics in web applications, including the principles and defenses of cross-site scripting (XSS) and cross-site request forgery (CSRF). The second half turns to classic Internet application protocols: composing and parsing email, sending with SMTP, retrieving with POP and IMAP, remote login with Telnet and SSH, and RPC. The book includes numerous runnable code listings and examples, and touches on practical topics such as configuring URLs in the Flask framework and writing asynchronous I/O event loops, helping readers turn protocol principles into working code.