Discuss the usage of templates in Laravel 5.0 version

Laravel is a popular PHP framework that provides many powerful features and tools to help develop high-quality web applications quickly. One of the important features is the template engine, which makes it easier for developers to build beautiful, reusable pages. This article will explore the usage of templates in Laravel 5.0 version and provide some practical tips and suggestions.

The foundation of Laravel5.0 template engine

Laravel5.0 uses the Blade template engine, which provides a series of template components and syntax to help quickly build beautiful pages. The Blade template engine has the following characteristics:

1. Concise syntax: Blade provides a concise syntax, making the template code more readable and maintainable.
2. Extensibility: Developers can extend the functions of the Blade template engine through custom instructions.
3. Support template inheritance: Blade allows developers to reuse page layouts and styles through template inheritance.

Laravel5.0 template engine syntax

The syntax of Blade template uses '{{}}' as a mark to indicate output template variables. For example:

<h1 id="title">{{ $title }}</h1>

In a template, we can use regular syntax such as 'if-else' statements, 'foreach' loops and 'include' to include other templates. For example:

@if(count($items) > 0)
    

    @foreach($items as $item)         
• {{ $item }}
    @endforeach     

@else     

No items

@endif @include('partials.footer')

In the above example, the 'if-else' statement checks whether the items variable is empty. If it is not empty, it uses a 'foreach' loop to traverse, and then passes the variable through '{{}}' Output to HTML. Finally, a template named 'partials.footer' is introduced via the '@include' directive.

Laravel5.0 template engine control structure

The Blade template engine provides some control structures for more complex logic processing. The following are some practical control structures:

1. @foreach loop:

@foreach($items as $item)
    

{{ $item }}

@endforeach

2. @for loop:

@for($i = 0; $i {{ $items[$i] }}
@endfor

3. @if condition:

@if(count($items))
    {{ $items[0] }}
@endif

4. @unless condition:

@unless(count($items))
    <p>No items found!</p>
@endunless

5. @include template contains:

@include('partials.header')

6. @extendsTemplate inheritance:

@extends('layouts.master')

@section('content')
    <p>This is the body.</p>
@endsection

In the above example, '@extends' specifies the layout inherited by the template, and '@section' defines the content block in the template. The content block in the parent template is rendered in the child template by using the '@yield' directive.

Laravel5.0 template layout inheritance

The Blade template engine allows developers to use layout inheritance to layout pages. By defining a main layout (called Master Layout) and a sublayout (called Child Layout), we can extend the main layout in the sublayout and define content blocks for various sections. The following example demonstrates how to create layout inheritance:

1. Main layout

<!-- resources/views/layouts/master.blade.php -->
nbsp;html>

    
        <title>@yield('title')</title>
        <link>
    
    
        @yield('content')
    

2. Child layout

<!-- resources/views/layouts/child.blade.php -->
@extends('layouts.master')

@section('title', 'My Home Page')

@section('content')
    <p>This will be displayed in the body.</p>
@endsection

In the above example, The child layout inherits the main layout and defines a section called 'content'. By using the '@yield' directive in the main layout, we can specify the position and content of the section. In a sublayout, use the '@section' directive to fill in the content of that section.

Error handling of Laravel5.0 templates

Error handling is very important when developing web applications. Through Laravel5.0's template engine, we can easily handle errors on the page. Here are some practical error handling tips:

1. Check if a variable exists:

{{ $foo or 'default' }}

In the above example, the default value will be displayed if the $foo variable is undefined 'default'.

2. Check if the expression is true:

{{ $foo ? 'yes' : 'no' }}

In the above example, if the $foo variable is true, it displays 'yes', otherwise it displays 'no' .

3. If some variables are undefined, use the default value:

{{ $foo or 'default' }}

In the above example, if the $foo variable is undefined, the default value 'default' will be used .

4. Check form errors:

@if(count($errors))
    <div>
        <ul>
        @foreach($errors->all() as $error)
            <li>{{ $error }}</li>
        @endforeach
        </ul>
    </div>
@endif

In the above example, use the @if statement to check whether the $errors variable is empty. If an error exists, an error message is output via the '@foreach' directive.

5. Check the current URL and add CSS class:

    Home

In the above example, use the 'Request::is()' method to check whether the current URL is 'home' , if yes, add CSS class 'active'.

Summary

In Laravel5.0, the template engine is a very important feature, which provides a convenient tool for developing large-scale web applications. In this article, we introduce the basic syntax and common techniques of the Blade template engine. If you have just started learning Laravel5.0, we strongly recommend that you study and practice the Blade template engine in depth. It will make you easier to use, faster and more flexible when developing web applications.

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