39. Conclusion
Let’s review the work done in this document:
Chapter | Code Repository | Contents |
Course Overview | ||
Setting up a work environment | ||
[Basics] | The basics of the Python language – language structures – data types – functions – console output – format strings – type conversion – lists – dictionaries – regular expressions | |
[strings] | String notation – methods of the <str> class – encoding/decoding strings in UTF-8 | |
[exceptions] | Exception handling | |
[functions] | Variable Scope – Parameter Passing – Using Modules – The Python Path – Named Parameters – Recursive Functions | |
[files] | Reading/writing a text file – handling UTF-8 encoded files – handling JSON files | |
[taxes/v01] | Version 1 of the application exercise: calculating income tax . The application is available in 18 versions – Version 1 implements a procedural solution | |
[imports] | Managing application dependencies by importing modules – a dependency management method is presented – it is used throughout the document – managing the Python Path | |
[impots/v02] | Version 2 of the application builds on version 1 by gathering all configuration constants into a configuration file that also manages the Python Path | |
[impots/v03] | Version 3 of the application builds on version 2 by using functions encapsulated in a module— dependency management is handled via configuration—introduction of a JSON file to read the data needed for tax calculation and write the calculation results | |
[classes/01] | Classes – inheritance – methods and properties – getters/setters – constructor – [__dict__] property | |
[classes/02] | Introduction to the [BaseEntity] and [MyException] classes used throughout the rest of the document – [BaseEntity] facilitates object/dictionary conversions | |
[three-layers] | Layered architecture and interface-based programming. This chapter presents the programming methods used throughout the rest of the document | |
[taxes/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] | |
[databases/mysql] | Installing the MySQL DBMS – connecting to a database – creating a table – executing SELECT, UPDATE, DELETE, and INSERT SQL statements – transactions – parameterized SQL queries | |
[databases/postgresql] | Installing the PostgreSQL DBMS – connecting to a database – creating a table – executing SELECT, UPDATE, DELETE, and INSERT SQL statements – transactions – parameterized SQL queries | |
[databases/anydbms] | Writing DBMS-independent code | |
[databases/sqlalchemy] | The SqlAlchemy ORM (Object- Relational Mapper) – an ORM allows for a unified approach to working with different DBMSs – mapping classes to SQL tables – operations on classes representing SQL tables | |
[taxes/v05] | Version 5 of the tax calculation application – Using the layered architecture from version 04 and the SqlAlchemy ORM to work with MySQL and PostgreSQL DBMSs | |
[inet] | Web Programming – TCP/IP Protocol (Transmission Control Protocol / Internet Protocol) – HTTP Protocols (HyperText Transfer Protocol) – SMTP (Simple Mail Transfer Protocol) – POP (Post Office Protocol) – IMAP (Internet Message Access Protocol) | |
[flask] | Web services with the Flask web framework – displaying an HTML page – JSON web service – GET and POST requests – managing a web session | |
[impots/http-servers/01] [taxes/http-clients/01] | Version 6 of the application exercise – Creating a JSON web service for tax calculation with a multi-layer architecture – Writing a web client for this server with a multi-layer architecture – client/server programming – using the [requests] module | |
[taxes/http-servers/02] [taxes/http-clients/02] | Version 7 of the application exercise – Version 6 is improved: the client and server are multithreaded – [Logger] utilities to log client/server exchanges – [SendMail] to send an email to the application administrator | |
[taxes/http-servers/03] [taxes/http-clients/03] | Version 8 of the application exercise – Version 7 is improved by the use of a web session | |
[xml] | XML (eXtended Markup Language) management with the [xmltodict] module | |
[taxes/http-servers/04] [impots/http-clients/04] | Version 9 of the application exercise – version 8 is modified to include client/server exchanges in XML; | |
[taxes/http-servers/05] [taxes/http-clients/05] | Version 10 of the application exercise – instead of processing N taxpayers via N GET requests, a single POST request is used with the N taxpayers in the POST body | |
[taxes/http-servers/06] [taxes/http-clients/06] | Version 11 of the application exercise – the application’s client/server architecture is modified: the [business] layer moves from the server to the client | |
[taxes/http-servers/07] | Version 12 of the application exercise – this version implements an MVC (Model–View– Controller) server that delivers JSON, XML, and HTML interchangeably, depending on the client’s request. This chapter implements the JSON and XML versions of the server | |
[impots/http-clients/07] | Implementation of the JSON and XML clients for the MVC server in Version 12 | |
[impots/http-servers/07] | Implementation of the HTML server in version 12 – using the Bootstrap CSS framework – | |
[impots/http-servers/08] | Version 13 of the application exercise – Refactoring the code from version 12 – session management using the [flask_session] module and a Redis server – using encrypted passwords | |
[impots/http-servers/09] [impots/http-clients/09] | Version 14 of the application exercise – implementing URLs with a CSRF (Cross-Site Request Forgery) token | |
[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’s state, and ADS (Action Do Something), which perform an action that modifies the server’s state—these actions all end with a redirect to an ASV action—this allows for proper handling of page refreshes in the client browser | |
[impots/http-servers/11] | Version 16 of the application – URL management with prefixes | |
[impots/http-servers/12] | Version 17 of the application – porting version 16 to an Apache/Windows server | |
[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 an MVC architecture:
The content of this document 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 the 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.