SOLID

 SOLID is an acronym that stands for five key design principles: Single responsibility principle, Open-closed principle, Liskov substitution principle, Interface segregation principle, and Dependency inversion principle. All five are used by software engineers and provide significant benefits to developers.

Principles of SOLID:

• SRP – Single Responsibility Principle

SRP states that, “a class should have one, and only one, reason to change.” Following this principle means that each class does only one thing and each class or module is responsible for only one part of the program functionality. For simplicity, each class should solve only one problem.

Single responsibility principle is a basic principle that many developers already use to create code. It can be used for classes, software components, and sub-services.

Applying this principle simplifies testing and maintaining the code, simplifies software implementation, and helps prevent unintended consequences of future changes.

• OCP – Open/Closed Principle

OCP states that software entities (classes, modules, methods, etc.) should be open for extension, but closed for modification.

Practically this means creating software entities whose behavior can be changed without the need to edit and compile the code itself. The easiest way to demonstrate this principle is to focus on the way it does one thing.

• LSP – Liskov Substitution Principle

LSP states that “any subclass object should be substitutable for the superclass object from which it is derived”.

While this may be a difficult principle to put in place, in many ways it is an extension of a closed principle, as it is a way to ensure that the resulting classes expand the primary class without changing behavior.

• ISP – Interface Segregation Principle

ISP principle states that “clients should not be forced to implement interfaces they do not use.”

Developers do not just have to start with an existing interface and add new techniques. Instead, start by creating a new interface and then let your class implement as many interactions as needed. Minor interactions mean that developers should prefer composition rather than legacy and by separation over merging. According to this principle, engineers should work to have the most specific client interactions, avoiding the temptation to have one large, general purpose interface.

• DIP – Dependency Inversion Principle

DIP – Dependency Inversion Principle states that “high level modules should not depend on low level modules; both should depend on abstractions. Abstractions should not depend on details.  Details should depend upon abstractions”

This principle offers a way to decouple software modules. Simply put, dependency inversion principle means that developers should “depend on abstractions, not on concretions.”

Benefits of SOLID principle

• Accessibility
• Ease of refactoring
• Extensibility
• Debugging
• Readability

REFERENCES:

1. https://www.bmc.com/blogs/solid-design-principles/

From the blog CS@Worcester – THE SOLID by isaacstephencs and used with permission of the author. All other rights reserved by the author.

As we continue to work with API’s, I have decided to dedicate this blogpost to talk about security with API’s as eventually we will have to take this into consideration when we go into more in depth with them in the future. Security will always stay priority in which I think it would be helpful to look at this area now. I have chosen a blog post that gives us some good practices we can look at to help better our API’s.

In summary, this authors first goes over TLS which stands for Transport layer security which is a cryptographic protocol used to help prevent tampering and eavesdropping by encrypting messages sent to and from the server. The absence of TLS means that third parties get easy access to private information from users. TLS can be found when the website URL contains https and not just http such as the very website you are reading from now. Then they go over Oauth2 which is a general framework and use that with single sign-on providers. This helps manage third party applications access and usage of data on the behalf of the user. This is used in situations such as granting access to photos to used in a different application. They go in depth over codes and authentication tokens with Oauth2. Then they go over API keys where we should set the permissions on those and don’t mismanage those. They say at the end to just use good, reliable libraries that you can put most of the work and responsibility onto so that we can can minimize the mistakes we can make.

These practices will help bolster my knowledge on the security placed within the API’s we are working with. This blogpost has helped me learn more on the general framework on what security measures are placed in the general API landscape. TLS looks to be a standard protocol used in 99% of websites you see but also makes me wonder on all of the websites that I have traversed through that didn’t have TLS and you should too and make sure that you have no private information in danger on those sites. This also makes me wonder on how TLS is implemented such as with the LibrePantry API that is being worked on if it is being used there(hopefully). Then perhaps when we work further in the API’s, we get to see the security practices implemented.

Source: https://stackoverflow.blog/2021/10/06/best-practices-for-authentication-and-authorization-for-rest-apis/

From the blog CS@Worcester – kbcoding by kennybui986 and used with permission of the author. All other rights reserved by the author.

When developing software, creating understandable, readable, and testable code is not just a nice thing to do, but it is a necessity. This is because having clean code that could be reviewed and worked on by other developers is an essential part of the development process. When it comes to object oriented programming languages, there are a few design principles that help you avoid design smells and messy code. These principles are known as the SOLID principles. These principles were originally introduced by Robert J. Martin back in 2000. SOLID is an acronym for five object oriented design principles. These principles are:

1. Single Responsibility Principle – A class should have one and only one reason to change, meaning that a class should have only one job. This principle helps keep code consistent and it makes version control easier.
2. Open Closed Principle – Objects or entities should be open for extension but closed for modification. This means that we should only add new functionality to the code, but not modify existing code. This is usually done through abstraction. This principle helps avoid creating bugs in the code.
3. Liskov Substitution Principle – Let q(x) be a property provable about objects of x of type T. Then q(y) should be provable for objects y of type S where S is a subtype of T. This means that subclasses can substitute their base class. This is expected because subclasses should inherit everything from their parent class. They just extend the parent class, they never narrow it down. This principle also helps us avoid bugs.
4. Interface Segregation Principle – A client should never be forced to implement an interface that it doesn’t use, or clients shouldn’t be forced to depend on methods they do not use. This principle helps keeps the code flexible and extendable.
5. Dependency Inversion Principle – Entities must depend on abstractions, not on concretions. It states that the high-level module must not depend on the low-level module, but they should depend on abstractions. This means that dependencies should be reorganized to depend on abstract classes rather than concrete classes. Doing so would help keep our class open for extension. This principle helps us stay organized as well as help implement the Open Closed Principle.

These design principles act as a framework that helps developers write cleaner, more legible code that allows for easier maintenance and easier collaboration. The SOLID principles should always be followed because they are best practices, and they help developers avoid design smells in their code, which will in turn help avoid technical debt.

https://www.digitalocean.com/community/conceptual_articles/s-o-l-i-d-the-first-five-principles-of-object-oriented-design#single-responsibility-principle

https://www.freecodecamp.org/news/solid-principles-explained-in-plain-english/

From the blog CS@Worcester – Fadi Akram by Fadi Akram and used with permission of the author. All other rights reserved by the author.