Want to sleep peacefully? 10 RegEx Tester for JavaScript, Python, PHP, Golang, Ruby, etc. ?” and constantly worry about it at the back of their head). I must say that whoever came up with the definitions of these principles certainly wasn’t thinking of less experienced developers. I just wonder where and how. When writing code, there are many specific principles that aim to make your code more maintainable: DRY, the single responsibility principle, the Law of Demeter, the open/closed principle, etc.These are great principles to follow, but it can be difficult to keep all of them in your head at once. Stripped of highfalutin jargon and distilled down to its most basic form, the principle of Interface Segregation has this to say: The more numerous, more specialized interfaces there are in your application, the more modular and less weird your code will be. Here’s what a typical controller method looks like in actual, production-level applications: We’ve all written code like this. This is indeed what many developers are doing, but they’re setting themselves up for failure. So, why does all this song and dance about “Single Responsibility” matter at all? The Law of Demeter, or Principle of Least Knowledge is a well-known software design principle for reducing coupling between collaborating objects. Copy all the code from this function, make a few changes, and call it a day? If you used a PDF-generation service and your code was littered with new ABCService() class, the day the business decided to use some other service would be the day remembered forever — for all the wrong reasons! This will confirm my notion that developers are really struggling to make sense of these “advanced” concepts, and I’ll be motivated to write on other such topics. . So, why are the codebases so complex that we feel like gutting ourselves? . Organize your code as if you’re writing a novel. Prefer single words for methods, interfaces, and packages. Instead of rewriting software components from scratch, a programmer can make use of an exist-ing component. But my heart goes out to the average developer who’s been doing things intuitively (or the way they were taught to him) and can make neither head nor tail of the SOLID principles. In fact, a Repository is a well known and accepted pattern that brings consistency, flexibility, and abstraction to your data access patterns. Change? The end result: a soupy mess that very few want to touch and nobody understands. Well, that was quite a tour! The sooner an error is found, the cheaper it is to fix it. In our case, we need to free ourselves from having to depend on the MilkyWay class, and instead depend on a generic, a type of PDF class (it will all become clear in a second). As long as you write software for a living, remember that it’s the ideal everyone is striving for. Interface Segregation . Just write it in one place, create a method and use it everywhere. A naïve approach might be to have everything in the same class. And by future-proof, I mean that it’s not ready to handle change without creating a mess. Tight coupling means a group of classes are highly dependent on one another which you should avoid in your code. Allow me to explain. Sounds like it’s something to do with segregating . Then, I learned the SOLID principles. And it’s easy to see what it does: register new users. In Object-Oriented Programming, several techniques have been discovered and refined to achieve this goal, right from these SOLID principles we are studying to common design patterns, enterprise patterns, architectural patterns, and whatnot. 2. You might still consider creating a separate file for each of these API types and copy the existing code, modifying it slightly. Based on 15+ years of experience, this book is my attempt to teach about the heuristics that are involved when writing loosely coupled, maintainable and readable unit tests. A few days go by, and now your client/employer is getting a mobile app developed, which means this route will be of no use for users registering from mobile devices. Refuse to use Ada. Quidquid latine dictum sit, altum sonatur. Probably the best managed WordPress cloud platform to host small to enterprise sites. A consistent style acts as a basic roadmap for reading code. In the Service Container in our example, we can write something like this: This is basically saying, anytime someone asks for an IPDFGenerator, hand them the MilkyWayPDFGenerator class. In case you have but have been putting this learning off to “someday”, well, let’s make sure today is that day! Just as bad design triggers more bad design, good design can trigger more good design. Writing good code, code that is modular and easy to maintain, isn’t that hard. Yeah, I know, it’s another of those OOPSisms that make no sense the first time. These extreme cases occur when each patch introduces multiple unwanted side-effects. Different people explain this differently, but for me, this principle is all about bringing discipline and focus into your code. Anyway, enough of it. Continuing our earlier discussion where we had ten different types of API, each of those now calls a single function UserService::createNewUser($request->all()); and be done with it. A lot more can be said about Liskov Substitution (look up its theory and read up on Covariant Types if you’re really feeling brave), but in my opinion, this much is enough for the average developer coming across these mysterious lands of patterns and principles for the first time. Rather, we should use a general form of this dependency (create an interface for PDF services, that is), and let something else handle its instantiation and pass it to us (in Laravel, we saw how the Service Container helped us do that). Why change?”, which is why I said earlier that if you read about this in different places, you’ll get related but somewhat different and potentially confusing definitions. What is SQL Injection and How to Prevent in PHP Applications? . This rule simply says that code that works with parent classes (or interfaces) should not break when those classes are replaced with child classes (or interface-implementing classes). If changes are needed in the user registration logic, the UserService class will see to it while the controller methods don’t need to change at all. This base interface might look something like this: And now, for your User model, you’re supposed to create a UserRepository that implements this interface; then, for your Customer model, you’re supposed to create a CustomerRepository that implements this interface; you get the idea. And gRPC. The world changes, business changes, and thus, code changes — no getting around that. For example, don’t write salary calculation code everywhere wherever you need the salary of an employee. Applications always change, and writing maintainable code is very important in software engineering. And whenever a change a needed in that class, it follows that we will need to change it only because that one specific responsibility has changed. Netsparker uses the Proof-Based Scanning™ to automatically verify the identified vulnerabilities with proof of exploit, thus making it possible to scan thousands of web applications and generate actionable results within just hours. A rough sketch of how we might write a wrapper class for our MilkyWay service is as follows: And just like this, whenever we have a new PDF service, we will write a wrapper class for it. Broadly speaking, we have Inheritance and Interfaces. One of the keys to maintainable code of any kind - not just JS - is documentation and commenting. Although there are dozens of useful rules and principles in writing clean code, I think most can be reduced to one of these three: Optimise for the reader of the code, not the writer. . If even one parameter were to differ, we would unknowingly keep on building more code on top of it, and one day we will have the kind of stinking mess whose only solution would be to take it down. T ransparent The consequences of change should be obvious in the code that is changing and in distant code that relies upon it; If what you've written in the past doesn't suit your needs today, it can be expensive to change. So, what does that mean? The point is, we shouldn’t create our interfaces blindly. The problem is that HTML and JSON are not the only API formats in the world (let’s just consider HTML pages to be an API for the sake of argument). To reach that point we must know two more key concepts: Laravel’s container bindings, and a very common technique called dependency injection. Let’s take an example: Imagine that you write a program that calls an external REST API endpoint, does some kind of processing with the received data and writes it to a CSV file. In short, the SRP says that a given module or class should have responsible for a single element of a program’s functionality, and thus have just a single reason to change. To a developer, maintainable code simply means “code that is easy to modify or extend”. Perhaps you’ve heard of the term “SOLID principles” before, perhaps not. If the code is written following standards, then it becomes easily maintainable for other programmers succeeding him as it has higher readability. Let’s see how this helps. In software development, Object-Oriented Design plays a crucial role when it comes to writing flexible, scalable, maintainable, and reusable code. At the heart of maintainability is carefully constructed code that is easy to read; code that is easy to dissect in order to locate the particular component relating to a given change request; code that is then easy to modify without the risk of starting a chain reaction of breakages in dependant modules. Eh?? .. }. This frees you from having to write code such as $account = new Account(); all the time and makes the code more testable (a topic for another day). And now imagine the horror in large-scale SaaS apps, as the complexity of the code is already quite high. . In all tutorials covering the Repository Pattern, you’re advised to create a common interface (called a Repository) which will define the methods needed to access or manipulate data. Before you start rolling your eyes, consider that logging or maintaining an audit trail is a good, real-world example of such “read-only” models. . Write code that can be easily tested. In fact, it might just be the easiest principle of the five to understand (well, err . Let’s move on! You’ll notice that this method does a good job of following the Single Responsibility Principle: it doesn’t attempt to walk through the HTML content passed to it and create a PDF (in fact, it doesn’t even know it’s been given HTML); instead, it passes on that responsibility to the specialized MilkyWay class, and presents whatever it gets, as a download. Simply because the folks that wrote the first version were in a hurry, and those who came later just kept adding to the mess. Remove Duplicate Code. The code you write should have the following qualities. Suppose tomorrow we feel that the MilkyWay service is too expensive (or, as it often happens, their customer support has become shitty); as a result, we tried out another service called SilkyWay and want to move to it. SOLID is the acronym for a set of practices that, when implemented together, makes the code more adaptive to change. And then there’s another one for SOAP. And why is that bad? If you’ve worked as a professional developer for more than three days, you know our jobs are anything but creative and exciting. For me, there is no alternative: writing maintainable software starts with the SOLID principles. While I agree with most of the answers that books are not (on their own), the best way to learn to write clean code, they are a great supplement to other things you might be doing (like reading code, getting your code reviewed, etc). What about a client who has a legacy system running on the XML format? Dependency Inversion Principle (DIP) The SOLID principle helps in reducing tight coupling. Suppose we need to add the functionality to convert a given HTML content (maybe an invoice?) Unlike other resources found on the web that provide examples that you do understand but then leave you wondering how they’d help you in real-world cases, let’s dive into something specific, a coding style we see over and over, and perhaps even write in our Laravel applications. This is being created and passed to us by the Service Container, as e discussed earlier. You'll love it. Because it greatly increases the chance of making a mistake and is a burden on the business (developer time spent on sorting out the mess). and most importantly, adaptive to change. Use OOPS concepts. Keep on working, of course! Opposite of tight coupling is loose coupling and your code is considered as a good code when it has loosely-coupled classes. Documentation and Files/Minification. That’s because the difference is only in names, and both the interface as well as the class have the same methods working in the same way, so our code will work as before. hmm, that doesn’t sound so bad, does it? If you optimise for the... Don’t repeat yourself (often abbreviated to DRY). General Principles. You can tell that the function is meant for routes defined in the web.php file; that is, traditional, server-rendered pages. A talk on writing Simple, Clean, Readable, Understanable, and eventually Mainteanable code Instead, we should create several smaller, specialized interfaces, letting classes implement those that are needed, and leaving out those that are not. Recently, I've been thinking hard about what makes code maintainable, and how towrite code to be maintainable. In addition, reusable code helps performance by making it possible to The same is the case with the Open-Closed Principle, and the ones to come are a step ahead in weirdness. Well, in simpler terms, that’s all this principle is saying: make sure your subclasses implement all the methods exactly as required, with the same number and type of arguments, and the same return type. Unless you have to work with other people’s code. The tables have turned, and that’s why we call this an inversion of dependencies. Code is read more than it’s written. The code is also cleaner and there’s no mention of API keys, etc. If the next version of the MilkyWay API changes the interface, our method will stop working. Avoid Ada. Let’s also suppose we have the paid subscription of a hypothetical service called MilkyWay, which will do the actual PDF generation. First one is SOLID. An important lesson from Domain Driven Design is the encapsulation of Domain logic in objects. Code that is consistently formattedis easier to read and, consequently, maintain. Modularization-Write reusable code. Follow the Open-Closed Principle! A global CDN and cloud-based web application firewall for your website to supercharge the performance and secure from online threats. Reusable code is essential to avoid duplicated effort in software development. (Side note: Special cases might still arise, and that is fine because no design is perfect. 3. I’m not going to start writing code in a totally different style from tomorrow just because some madman who once wrote a book (and is now dead) says so.”. Let’s see an example before I explain my interpretation. When I came across this the first time, the definition I was presented with was, “There should be one, and only one reason for a class to change”. Our example might have been a bit simpler, but imagine what mess can be created when several classes have implemented methods they didn’t want, or those they wanted but were missing in the interface. If we were to take this logic out of the function and put it in a separate class, we’d now have two classes, each with a single responsibility to handle. This interest has partly been driven by thementoring of those starting out in C++ that I've been doing, both through theACCU mentored developers program, and for work. In the example we discussed, I might have created two interfaces instead of one:  IReadOnlyRespository (containing the functions getOne() and getAll()), and IWriteModifyRepository (containing the rest of the functions). About 20% of these techniques can't be used in Ada. To me, maintainable code doesn't take advantage of quirky language features that 0.1% of the programming population is aware of (i.e. Prefer single letter variables for loops and branches, single words for parameters and return values, multiple words for functions and package level declarations. 8 Reliable Laravel Hosting for Small to Big Sites. . Although testing every possible scenario can be time-consuming, you should definitely implement automated unit testing because it allows you to see what needs to be fixed when you make changes. Now, if the service we want to use (MilkyWay, in our case) doesn’t follow this interface, it’s our job to write a class that does that. And we also shouldn’t make assumptions, no matter how experienced or smart we think we are. Now, while we can do absolutely nothing about the former, we can do a lot about the latter. You might even want to create a separate interface for every method, and that will be fine too, assuming your project’s needs are that granular.). So if we're writing code, we need to write code that can be changed. Writing maintainable code Unless you write prototypes or applications that never make it past release 1, you’ll soon find yourself maintaining and extending existing code bases. You save the line of codes, scale and extension time, creates easy understanding, minimize the chances of errors. Sometimes this idea is expressed by saying that the interface is “fat”, but it means the same thing — the interface makes too many assumptions, and thus adds methods that are useless to some classes but still those classes are forced to implement them, resulting in brittle, confusing code. While these classes can take help from each other by calling their methods, they are not allowed to know what’s going on inside the other one. The Law of Demeter, or Principle of Least Knowledge is a well-known software design principle for reducing coupling between collaborating objects. And I’ve done my best to keep the examples as close to a Laravel developer’s workday as possible; after all, what use to us are examples that contain Vehicle and Car classes — or even advanced generics, reflection, etc. Let’s look at a very common and practical example. And change is inevitable. Look at the code now: much more compact, easy to understand . This is a guide to writing reusable and maintainable code using the C language. Once you get to this point, your stylesheets become unmaintainable. WTF is this MilkyWay? Netsparker Web Application Security Scanner. Regardless, let’s look at the definition found everyone for this principle: Classes should be open for extension but closed for modification. Guess what, that’s it! If you have ever inherited bad CSS with the obligation of maintaining it, you might have felt some empathy towards others who would maintain your code in the future. For regular repositories, I’d then say class UserRepository implements IReadOnlyRepository, IWriteModifyRepository { . Until later! With that understood, let’s create an interface that specifies which methods we want all of our PDF engine classes to contain: Through this interface, we’re saying that we expect all our PDF classes to have at least those three methods. Code that is Transparent, Reasonable, Usable, and Exemplary (TRUE) not only meets today’s needs but can also be changed to meet the needs of the future. The first step in creating code that is TRUE is to ensure that each class has a single, well-defined responsibility. 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