The Programming Arsenal

In this post, we will look at these few patterns that has been used in one or the other form throughout every programmers career. We will cover proxy, facade and adapter pattern, because they tend to be confusing and more importantly, doing it together will give us opportunity to compare and contrast them.

One best example that can be used as an analogy is the episode of “Batman: The Animated Series”, in which Batman is unwell or missing and Gotham needs him. Superman decides to fill in his shoes, to keep the Gotham city’s criminals at bay and give the impression that Batman is still on the prowl. You can see the fight between Batman (disguised Superman) and Bane.

How I created my editorial calendar and social media marketing tool with airtable and integromat

Ever since I started blogging, I needed a way to manage my blogging schedule and I also learned that I must use social media for blog promotion. The problem is, I hate spending time on social media and so, I needed a way to do it through automation.

After some research, I found out that there are some amazing apps, which I could use for all my blogging needs. Then I started to question what my…

Command Query Segregation implemented with python

In this last article, we created a simple analytics engine. It wasn’t really a proper engine, but a good example to bring us to the point where we do create something resembling one and here we are!

In this article, we will look at CQRS and see how rather not easy it is to generally go about that way. Of course, it will feel like that, because it is an overkill for a toy example.

But, the…

Producer-Consumer example comparing threading and asyncio

Producer consumer is a common problem for those wanting to learn about concurrency and it tends to be the one of the first problem that we learn about, while experimenting with any kind of concurrency code.

In this post, we will compare the producer-consumer example written in using multi-threading approach with the one written using asyncio approach.

Multi-threading Approach

Multi-…

OOPs! A land mine in the python land

I started writing proper softwares, not the scripts, from the final year of my engineering when I had to submit a project. I had tried many languages during my college years; starting with perl, c, c++, php and ended up with Java. I loved java because it was sold as the best language. And it seemed one too. Since it supported object orientation and ability to run everywhere and so on. Once I…

I’m writing a series of blog posts to explain how to use the clean architecture philosophy in python language. Here are the links:

General concept about clean architecture: https://progarsenal.com/clean-architecture/

First go at building your own analytics engine for website tracking using flask, sqlalchemy and good design principles: https://progarsenal.com/pythons-example-of-cleaner-architecture-series-1/

Python’s implementation of factory and abstract factory pattern

Design patterns are all the rage for all the new developers who want to up their skills. 

In the world of python, design patterns haven’t really caught up much as the language is dynamic and design patterns were more geared towards hiding complexity in the static  languages like C/C++, Java, .NET. 

In this post, we will be looking at two such patterns from the creational design patterns…

When they say full stack engineer, sympathise with them

Computer software development is a relatively new field when compared to building roads, houses and most things that humans have been doing for thousands of years. It changed the world, even unchained it when it came to information flow. But then, it went wrong!

What do we mean by: it went wrong? The idea of rebel hacker has seeped into the mindset of many developers, engineers and a lot of…

Python’s example of cleaner architecture series – 1

Disclaimer: I’ve used yuml.me to create the diagrams and would like to give a shout out to the great product it is.

Here is a much needed tutorial series on how to implement clean architecture in a python project. Although, I do not claim it to be a perfect representation of the clean philosophy but it does show how to ensure there’s a proper dependency management between components. We will…

Async Core – multiprocessing and asyncio based solution for backend services

The why?

Although, there have been great products that existing since a long time, which does exactly and more than what this project is trying to accomplish, namely – Celery. However, the basic premise of this effort is again based on a very simple idea, which happens to be the mainstay of python community and that is – KISS. Most of the time, a project begins humbly with small code based and…

Have you ever thought to yourself, heck why don’t python have a switch statement? I you have, then this post is for you! Python lacks switch statements and if you ask why, then the most people would point to if – elif – else chain as sufficient replacement for it.

If we have a situation where we want there to be one of the possible outcomes, based on the variable given then switch statement is a good way to go about it. Following is how you will see that happening:

// C style switch statements switch (variable) { case 1: // statements break; case 2: // statements break; case 3: // statements break; default: //statments }

In case of python, it would be something like the following:

if variable is 1: pass elif variable is 2: pass elif variable is 3: pass else: pass

There is one problem, however. It is a common understanding that in case of switch statements, the order also matters. So for example, case 1 must be checked before case 2 then that is what will happen and we can ensure that. The same can be said about the if-elif-else mechanism. We can ensure the order by appropriately placing the if and elif conditions in a certain order. The only problem with that is, the reader of the code will not expect this in case of python, unless there is a comment to explain that. In case of c style switch statement, the reader of the code is aware of the order and would only change the order consciously. Same cannot be said for if else statements. The reader might not even consider the order and will have to be sure what the conditions mean and if the order could matter. There’s too much context involved in reading a code like that.

Bring your own switch statement

If you are sure that the order plays an important role in the condition you are about to write then instead of letting it be an inline condition, you can encapsulate that in a switching function. It will be clear with the following example. Let’s say in the above condition we want to make sure that case 1 must be checked before any of the cases, then we can do the following:

def switch_my_case(variable): if variable is 1: # statements return # whatever needs to be returned if variable is 2: pass elif variable is 3: pass else: pass

What this does is that it ensures that the reader of the code understands just by looking at the code that the order somehow matters. Even if the reader is missing the context, this kind of flow invites the reader to gain that context. Another question that needs to be answered is: why a separate function and not do this inline? Well, the answer is simple: conditional returns. It behaves like break statements in c style switch cases. In case of looping condition, you can leverage the continue / break, but for general statements, there’s no conditional flow breaker without having to use more jumps, a multilevel condition. I would be interested in finding out if there are other ways to go about this without the verbosity of adding additional method for such scenario. Do comment and let me know how I can improve on this.

Why Python’s if elif else cannot be a replacement for switch statements

Have you ever thought to yourself, heck why don’t python have a switch statement? I you have, then this post is for you! Python lacks switch statements and if you ask why, then the most people would point to if – elif – else chain as sufficient replacement for it.

If we have a situation where we want there to be one of the possible outcomes, based on the variable given then switch statement…

Python Asyncio + cython + lua

To begin, I would first like to answer the obvious question: Why would anyone want to use lua when already using python? The answer is simple, legacy code. This experiment arose from the evaluation of possible candidates to replace an existing c/c++ system with limited throughput in terms of request per second with something like python or erlang. In this post, we will be focussing on python,…