- Introduction
- Template Inheritance
- Displaying Data
- Control Structures
- Service Injection
- Extending 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. All Blade views are compiled into plain PHP code and cached until they are modified, meaning Blade adds essentially zero overhead to your application. Blade view files use the .blade.php file extension and are typically stored in the resources/views directory.
Two of the primary benefits of using Blade are template inheritance and sections. To get started, let's take a look at a simple example. First, we will examine a "master" page layout. Since most web applications maintain the same general layout across various pages, it's convenient to define this layout as a single Blade view:
<!-- Stored in resources/views/layouts/master.blade.php -->
<html>
<head>
<title>App Name - @yield('title')</title>
</head>
<body>
@section('sidebar')
This is the master sidebar.
@show
<div class="container">
@yield('content')
</div>
</body>
</html>
As you can see, this file contains typical HTML mark-up. However, take note of the @section and @yield directives. The @section directive, as the name implies, defines a section of content, while the @yield directive is used to display the contents of a given section.
Now that we have defined a layout for our application, let's define a child page that inherits the layout.
When defining a child page, you may use the Blade @extends directive to specify which layout the child page should "inherit". Views which @extends a Blade layout may inject content into the layout's sections using @section directives. Remember, as seen in the example above, the contents of these sections will be displayed in the layout using @yield:
<!-- Stored in resources/views/layouts/child.blade.php -->
@extends('layouts.master')
@section('title', 'Page Title')
@section('sidebar')
@@parent
<p>This is appended to the master sidebar.</p>
@endsection
@section('content')
<p>This is my body content.</p>
@endsection
In this example, the sidebar section is utilizing the @@parent directive to append (rather than overwriting) content to the layout's sidebar. The @@parent directive will be replaced by the content of the layout when the view is rendered.
Of course, just like plain PHP views, Blade views may be returned from routes using the global view helper function:
Route::get('blade', function () {
return view('child');
});
You may display data passed to your Blade views by wrapping the variable in "curly" braces. For example, given the following route:
Route::get('greeting', function () {
return view('welcome', ['name' => 'Samantha']);
});
You may display the contents of the name variable like so:
Hello, {{ $name }}.
Of course, you are not limited to displaying the contents of the variables passed to the view. You may also echo the results of any PHP function. In fact, you can put any PHP code you wish inside of a Blade echo statement:
The current UNIX timestamp is {{ time() }}.
Note: Blade
{{ }}statements are automatically sent through PHP'shtmlentitiesfunction to prevent XSS attacks.
Since many JavaScript frameworks also use "curly" braces to indicate a given expression should be displayed in the browser, you may use the @ symbol to inform the Blade rendering engine an expression should remain untouched. For example:
<h1>Laravel</h1>
Hello, @{{ name }}.
In this example, the @ symbol will be removed by Blade; however, {{ name }} expression will remain untouched by the Blade engine, allowing it to instead be rendered by your JavaScript framework.
Sometimes you may wish to echo a variable, but you aren't sure if the variable has been set. We can express this in verbose PHP code like so:
{{ isset($name) ? $name : 'Default' }}
However, instead of writing a ternary statement, Blade provides you with the following convenient short-cut:
{{ $name or 'Default' }}
In this example, if the $name variable exists, its value will be displayed. However, if it does not exist, the word Default will be displayed.
By default, Blade {{ }} statements are automatically sent through PHP's htmlentities function to prevent XSS attacks. If you do not want your data to be escaped, you may use the following syntax:
Hello, {!! $name !!}.
Note: Be very careful when echoing content that is supplied by users of your application. Always use the double curly brace syntax to escape any HTML entities in the content.
In addition to template inheritance and displaying data, Blade also provides convenient short-cuts for common PHP control structures, such as conditional statements and loops. These short-cuts provide a very clean, terse way of working with PHP control structures, while also remaining familiar to their PHP counterparts.
You may construct if statements using the @if, @elseif, @else, and @endif directives. These directives function identically to their PHP counterparts:
@if (count($records) === 1)
I have one record!
@elseif (count($records) > 1)
I have multiple records!
@else
I don't have any records!
@endif
For convenience, Blade also provides an @unless directive:
@unless (Auth::check())
You are not signed in.
@endunless
In addition to conditional statements, Blade provides simple directives for working with PHP's supported loop structures. Again, each of these directives functions identically to their PHP counterparts:
@for ($i = 0; $i < 10; $i++)
The current value is {{ $i }}
@endfor
@foreach ($users as $user)
<p>This is user {{ $user->id }}</p>
@endforeach
@forelse ($users as $user)
<li>{{ $user->name }}</li>
@empty
<p>No users</p>
@endforelse
@while (true)
<p>I'm looping forever.</p>
@endwhile
Blade's @include directive, allows you to easily include a Blade view from within an existing view. All variables that are available to the parent view will be made available to the included view:
<div>
@include('shared.errors')
<form>
<!-- Form Contents -->
</form>
</div>
Even though the included view will inherit all data available in the parent view, you may also pass an array of extra data to the included view:
@include('view.name', ['some' => 'data'])
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:
{{-- This comment will not be present in the rendered HTML --}}
The @inject directive may be used to retrieve a service from the Laravel service container. The first argument passed to @inject is the name of the variable the service will be placed into, while the second argument is the class / interface name of the service you wish to resolve:
@inject('metrics', 'App\Services\MetricsService')
<div>
Monthly Revenue: {{ $metrics->monthlyRevenue() }}.
</div>
Blade even allows you to define your own custom directives. You can use the directive method to register a directive. When the Blade compiler encounters the directive, it calls the provided callback with its parameter.
The following example creates a @datetime($var) directive which formats a given $var:
<?php
namespace App\Providers;
use Blade;
use Illuminate\Support\ServiceProvider;
class AppServiceProvider extends ServiceProvider
{
/**
* Perform post-registration booting of services.
*
* @return void
*/
public function boot()
{
Blade::directive('datetime', function($expression) {
return "<?php echo with{$expression}->format('m/d/Y H:i'); ?>";
});
}
/**
* Register bindings in the container.
*
* @return void
*/
public function register()
{
//
}
}
As you can see, Laravel's with helper function was used in this directive. The with helper simply returns the object / value it is given, allowing for convenient method chaining. The final PHP generated by this directive will be:
<?php echo with($var)->format('m/d/Y H:i'); ?>