Category: Programming

An absolutely clean domain or just common sense

Nowadays, a concept like DDD is widely known and used by many programmers. Curious programmers read a lot about those practices in books written by Evans or Vernon or maybe have knowledge from conferences or blogs. As I saw many times, people are trying to be too much strict with these practices. Trying to make a domain completely clean is of course highly desired, but if you have a not very complex domain, and to have a completely clean domain you need to highly complicate the code around it (probably Infrastructure’s code) something is wrong, don’t you think? So you need to think about the return on investment. Is it worth having more work to do, and complex infrastructure code to just make your domain completely clean? In most cases probably it isn’t at all, only in projects with a highly complicated domain it will be necessary to define a core domain, and then perhaps making this core domain completely clean will make sense. However, not every place in your project will be perfect, you should invest your time only in the most important places. So in this article, I would like to write about using ORMs when approaching DDD which are often hated by many people.

Unit testing tips by examples in PHP

In these times, the benefits of writing unit tests are huge. I think that most of the recently started projects contain any unit tests. In enterprise applications with a lot of business logic, unit tests are the most important tests, because they are fast and can us instantly assure that our implementation is correct. However, I often see a problem with good tests in projects, though these tests’ benefits are only huge when you have good unit tests. So in these examples, I will try to share some tips on what to do to write good unit tests.

Circuit Breaker

In most systems, we use remote calls. Many factors may have an impact on these remote calls e.g. network latency, server availability and so on. So we should assume that something can go wrong. These calls can be potential bottlenecks, we don’t want user waiting for the response from the server very long, because external API is very slow or not available. Also if we have a few services which communicate with each other we shouldn’t aggravate the situation when one of them has too much traffic and slow down significantly. So how to do it correctly?

Mutation testing – we are testing tests

Writing tests should assure us that the code created by us is working correctly. Often we point out the code coverage factor and if we have 100% we can say that implemented solutions are correct. Are you sure? Maybe there is a tool that can give us more accurate feedback?

Entity should always be valid

Very often in projects using Doctrine, in entity there are mapping for fields also for each field there are getters and setters. In addition, for each field, we have validation annotations, and forms are validating on the entity. Is this the right approach?

Active record (Eloquent) vs Data mapper (Doctrine)

In the most of systems need to save data somewhere and in some way. ORM (Object-Relational Mapping), is the way of mapping the system to the database. ORM is the layer between database and application which deals with creating, updating, reading and deleting.

Service locator vs Dependency injection

During designing application, we are making new classes. Classes have dependencies. In programming we distinguish two patterns for managing class’s dependencies:

Dependency injection
Service locator