Object Oriented Programming with Laravel - Session 3
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The document discusses various concepts in object-oriented programming and Laravel's Blade templating engine, including: 1) Final methods, interfaces, abstract classes, and the differences between interfaces and abstract classes. 2) What a template engine is and how controllers use it to generate HTML. Blade is the template engine included with Laravel. 3) How Blade templates work, template inheritance using extends, displaying data, and features like comments, includes, and rendering collections.
Object Oriented Programming with Laravel - Session 3
- 1. Object-Oriented Programming (with Laravel) By: Shahrzad Peyman Session 3 April-2017 [email protected] 1
- 2. 2 Today’s Presentation • Final Methods • Interface • Abstract • Template Engine • Blade • Template Inheritance • Blade Syntax
- 3. Final Methods Most of the time, allowing your classes to be extended using inheritance is a good thing. It's part of what makes object-oriented programming so powerful. Occasionally, though, overriding certain methods of a class can cause things to break easily, create security issues, or make the resulting code overly complex. When you wish to prevent a subclass from overriding a superclass method, you can use the final keyword. 3
- 5. 5 Interface An interface is an outline of what a particular object can do. You will often hear that an interface is a contract. This is true in as much as an interface defines the public methods that a class must implement. Object interfaces allow you to create code which specifies which methods a class must implement, without having to define how these methods are handled.
- 6. Interface 6
- 7. Abstract 7 An abstract class is a special type of class that can't be instantiated — in other words, you can't create objects from it. Instead, you create child classes from the abstract class, and create objects from those child classes instead. An abstract class is designed to be used as a template for creating classes. An abstract class will have abstract methods which are defined by the abstract keyword, these methods are like the methods defined in the interface classes.
- 8. 8 Abstract
- 9. Interface vs Abstract Interface Abstract The Code • abstract methods • constants • abstract methods • constants • concrete methods • concrete variables Access Modifiers • public • public • private • protected Number of Parents Class can impelement more than one interface Class can inherit only from one abstract class 9
- 10. What is template engine? Template Engine, combines web templates to form finished web pages, possibly using some data source to customize the pages or present a large amount of content on similar-looking pages. As you know, the controller is responsible for handling each request that comes into a Laravel application. When a controller needs to generate HTML, CSS or any other content, it hands the work off to the templating engine. 10
- 12. Template 12 A template is simply a text file that can generate any text-based format (HTML, XML, CSV, LaTeX ...). The most familiar type of template is a PHP template - a text file parsed by PHP that contains a mix of text and PHP code.
- 13. Blade Blade is the simple, yet powerful templating engine provided with Laravel. Unlike other popular PHP templating engines, Blade does not restrict you from using plain PHP code in your views. In fact, all Blade views are compiled into plain PHP code and cached until they are modified, meaning Blade adds essentially zero overhead to your application.
- 14. Blade Blade view files use the .blade.php file extension and are typically stored in the resources/views directory. Every template name also has two extensions that specify the format and engine for that template. Views contain the HTML served by your application and separate your controller / application logic from your presentation logic.
- 15. Template Inheritance Defining a Layout: Two of the primary benefits of using Blade are template inheritance and sections.
- 16. Template Inheritance 16 Extending a Layout: When defining a child view, use the Blade @extends directive to specify which layout the child view should "inherit".
- 17. Routes & Blade Views Blade views may be returned from routes using the global view helper: 17
- 18. Components & Slots 18 Components and slots provide similar benefits to sections and layouts; however, some may find the mental model of components and slots easier to understand.
- 20. Displaying Data You may display data passed to your Blade views by wrapping the variable in curly braces. 20
- 21. Displaying Data When passing information in this manner, $data should be an array with key/value pairs. Inside your view, you can then access each value using its corresponding key. You can do: 21
- 22. 22 Displaying Data Of course, you are not limited to displaying the contents of the variables passed to the view. You may also echo the results of any PHP function. In fact, you can put any PHP code you wish inside of a Blade echo statement: If you do not want your data to be escaped, you may use the following syntax:
- 23. 23 Sharing Data with All Views Occasionally, you may need to share a piece of data with all views that are rendered by your application.
- 24. 24 Blade & JavaScript Framework Since many JavaScript frameworks also use "curly" braces to indicate a given expression should be displayed in the browser, you may use the @ symbol to inform the Blade rendering engine an expression should remain untouched. For example:
- 25. 25 Blade & JavaScript Framework If you are displaying JavaScript variables in a large portion of your template, you may wrap the HTML in the @verbatim directive so that you do not have to prefix each Blade echo statement with an @ symbol:
- 26. If Statements 26
- 27. Loops 27
- 28. 28 Loops
- 29. 29 Loops
- 30. 30 Comments Blade also allows you to define comments in your views. However, unlike HTML comments, Blade comments are not included in the HTML returned by your application:
- 31. 31 Including Sub-Views Blade’s @include directive allows you to include a Blade view from within another view. All variables that are available to the parent view will be made available to the included view:
- 32. 32 Rendering Views For Collections