39. Conclusion

Let’s review the work done in this document:

Chapter	File	Contents
Chapter 1		Course Overview
Chapter 2		Setting Up a Work Environment
Chapter 3	[bases]	The basics of the Python language – language structures – data types – functions – console output – format strings – type conversion – lists – dictionaries – regular expressions
Chapter 4	[strings]	String notation – methods of the <str> class – encoding/decoding strings in UTF-8
Chapter 5	[exceptions]	Exception handling
Chapter 6	[fonctions]	Scope of variables – parameter passing – using modules – Python Path – named parameters – recursive functions
Chapter 7	[fichiers]	Reading/writing a text file – handling UTF-8 encoded files – file management jSON
Chapter 8	[impots/v01]	Version 1 of the application exercise: an income tax calculation. The application is available in 18 versions – version 1 implements a procedural solution
Chapter 9	[imports]	Managing application dependencies by importing modules – a dependency management method is presented – it is used throughout the document – Python management Path
Chapter 10	[impots/v02]	The version 2 of the application builds on version 1 by gathering all configuration constants into a configuration file
Chapter 11	[impots/v03]	The version 3 of the application builds on version 2 by using functions encapsulated in a module—dependency management is handled via configuration – introduction of the jSON file to read the data needed to calculate the tax and write the calculation results
Chapter 12	[classes/01]	Classes – inheritance – methods and properties – getters / setters – constructor – [__dict__] property
Chapter 13	[classes/02]	Overview of the [BaseEntity] and [MyException] classes used in the rest of the document – [BaseEntity] facilitates object/dictionary conversions
Chapter 14	[troiscouches]	Layered architecture and interface-based programming. This chapter presents the programming methods used in the rest of the document
Chapter 15	[impots/v04]	Version 4 of the application – this version implements a solution with a layered architecture, interface-based programming, and the use of classes derived from [BaseEntity] and [MyException]
Chapter 16	[databases/mysql]	Installing SGBD MySQL – connecting to the database – creating a table – executing commands SQL SELECT, UPDATE, DELETE, INSERT – transaction – configured queries SQL
Chapter 17	[databases/postgresql]	Installation of SGBD PostgreSQL – database connection – table creation – execution of commands SQL SELECT, UPDATE, DELETE, INSERT – transaction – configured queries SQL
Chapter 18	[databases/anysgbd]	Writing code independent of SGBD
Chapter 19	[databases/sqlalchemy]	The ORM (Object Relational Mapper) SqlAlchemy – a ORM allows for unified work with different SGBD - mapping classes / tables SQL – operations on table image classes SQL
Chapter 20	[impots/v05]	Version 5 of the tax calculation application – Using the layered architecture of version 04 andORM SqlAlchemy to work with the SGBD MySQL and PostgreSQL
Chapter 21	[inet]	Internet Programming – TCP / IP Protocol (Transfer Control Protocol / Internet Protocol) – HTTP Protocols (HyperText Transfer Protocol) – SMTP (Simple Mail Transfer Protocol) – POP (Post Office Protocol) – IMAP (Internet Message Access Protocol)
Chapter 22	[flask]	Web services with the Flask web framework – displaying a page HTML – web service jSON – requests GET and POST – managing a web session
Chapter 23	[impots/http-servers/01] [impots/http-clients/01]	Version 6 of the application exercise - Creating a web service jSON for tax calculation with a multi-tier architecture - Writing a web client for this server with a multi-tier architecture – client/server programming – using the [requests] module
Chapter 24	[impots/http-servers/02] [impots/http-clients/02]	Version 7 of the application release – version 6 has been improved: the client and server are multithreaded – utilities [Logger] to log client/server exchanges – [SendMail] to send an email to the application administrator
Chapter 25	[impots/http-servers/03] [impots/http-clients/03]	Version 8 of the application exercise – version 7 is improved by using a session
Chapter 26	[xml]	Management XML with the [xmltodict] module
Chapter 27	[impots/http-servers/04] [impots/http-clients/04]	Version 9 of the application exercise – version 8 is modified to have client/server exchanges in XML;
Chapter 28	[impots/http-servers/05] [impots/http-clients/05]	Version 10 of the application exercise – instead of processing N taxpayers via N GET requests, a single request POST is used with the N taxpayers in the body of POST
Chapter 29	[impots/http-servers/06] [impots/http-clients/06]	Version 11 of the application year – the application’s client/server architecture is modified: the [métier] layer moves from the server to the client
Chapter 30	[impots/http-servers/07]	Version 12 of the application exercise – this version implements a MVC server (Model – View – Controller) that delivers, at the client’s request, either jSON, XML, or HTML. This chapter implements the jSON and XML versions of the server
Chapter 31	[impots/http-clients/07]	Implementation of clients, jSON, and XML of the MVC server from version 12
Chapter 32	[impots/http-servers/07]	Implementation of the HTML server from the version 12 – using the CSS Bootstrap framework –
Chapter 33	[impots/http-servers/08]	Version 13 of the application exercise - Refactoring the code from version 12 – session management with the [flask_session] module and a Redis server – using encrypted passwords
Chapter 34	[impots/http-servers/09] [impots/http-clients/09]	Version 14 of the application exercise – implementation of URL with a token CSRF (Cross-Site Request Forgery)
Chapter 35	[impots/http-servers/10]	Version 15 of the application exercise – refactoring the code from version 14 to handle two types of actions: ASV (Action Show View), which are used only to display a view without modifying the server state, ADS (Do Something Action) which performs an action that changes the server’s state – these actions all end with a redirect to a ASV action – this allows for proper handling of client browser page refreshes
Chapter 36	[impots/http-servers/11]	Version 16 of the application – management of URL with prefix
Chapter 37	[impots/http-servers/12]	Version 17 of the application – porting version 16 to an Apache / Windows server
Chapter 38	[impots/http-servers/13]	Version 18 of the application – fixes a bug in version 17

The client/server tax calculation applications have implemented the following architecture:

The [web] layer above was implemented using a MVC architecture:

The document’s content is dense. Readers who make it to the end will gain a solid understanding of MVC web programming in Python/Flask and, beyond that, a solid understanding of MVC web programming in other languages.

Additional information on the Flask framework can be found in the document [https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world] by author Miguel Grinberg. I have read some sections of his course, and they struck me as very educational. The author covers many concepts not addressed in this document.