search
HomeBackend DevelopmentPHP TutorialLaravel 的 Events 及 Observers(五)

首先,我们为你展示如何通过模型观察者实现前面模式事件中的第一个例子。

在 app/Observers文件夹中创建  WelcomeUserObserver.php文件,并加入下面的代码:

<?php  namespace App\Observers;  class WelcomeUserObserver {    public function created($user){      Mail::send('emails.welcome', ['user' => $user], function($message) use ($user)      {          $message->to($user->email, $user->first_name . ' ' . $user->last_name)->subject('Welcome to My Awesome App, '.$user->first_name.'!');      });    }  }

然后在 EventServiceProvider的 boot()方法中注册该观察者:

/**   * Register any other events for your application.   *   * @param  \Illuminate\Contracts\Events\Dispatcher  $events   * @return void   */  public function boot(DispatcherContract $events)  {      parent::boot($events);      User::observe(new WelcomeUserObserver);  }

这样就 OK 了!现在你的观察者已经与模型关联起来了。

下面我们假设另一种情况。图书管理员对代码提出了一些新的需求:

  • 当添加一个新的作者的时候,每一个用户都收到一条通知
  • 每次添加/删除作者的时候,都发送一封邮件
  • 最后,每次删除一本书的时候,图书管理员都要知道数据库中有多少作者是没有与相关的图书的

好了,下面我们就开始吧。我们需要三个单独的类(请记住我们的 单一职责原则): CustomerNewAuthorObserver、 LibrarianAuthorObserver、 AuthorsWithoutBooksObservers。

注意:你可以按自己喜欢的方式命名这些类,我们这里只是选择比较容易与所选行为关联起来的名称。

下面我们分别来创建三个类:

<?php  // file: app/Observers/CustomerNewAuthorObserver  namespace App\Observers;  class CustomerNewAuthorObserver {    public function created($author)    {    }  }<?php  // file: app/Observers/LibrarianAuthorObserver  namespace App\Observers;  class LibrarianAuthorObserver {    public function created($author)    {    }    public function deleted($author)    {    }  }<?php  // file: app/Observers/AuthorsWithoutBooksObservers  namespace App\Observers;  class AuthorsWithoutBooksObservers {    public function deleted($author)    {    }  }

好了,现在应该添加一些逻辑了,首先为 CustomerNewAuthorObserver添加:

<?php  // file: app/Observers/CustomerNewAuthorObserver  namespace App\Observers;  class CustomerNewAuthorObserver {    public function created($author)    {      // getting all users...      $users = \App\User::all();      foreach($users as $user)      {        Mail::send('emails.created_author_customer', ['author' => $author], function($message) use ($user)        {            $message->to($user->email, $user->first_name . ' ' . $user->last_name)->subject('New Author Added!');        });      }    }  }

注意:我知道这是一种非常简单粗暴的方法,这里只是为了实现上面的目的。实际情况中可以使用 邮件队列。

<?php  // file: app/Observers/LibrarianAuthorObserver  namespace App\Observers;  class LibrarianAuthorObserver {    public function created($author) {      Mail::send('emails.created_author_librarian', ['author' => $author], function($message) use ($author)      {          $message->to('librarian@awesomelibrary.com', 'The Librarian')->subject('New Author: ' . $author->first_name . ' ' . $author->last_name);      });    }    public function deleted($author) {      Mail::send('emails.deleted_author_librarian', ['author' => $author], function($message) use ($author)      {          $message->to('librarian@awesomelibrary.com', 'The Librarian')->subject('New Author: ' . $author->first_name . ' ' . $author->last_name);      });    }  }

最后:

<?php  // file: app/Observers/AuthorsWithoutBooksObservers  namespace App\Observers;  class AuthorsWithoutBooksObservers {    public function deleted($author) {      $authorsWithoutBooks = \App\Author::has('books', '=', 0)->get();      if(count($authorsWithoutBooks) > 0){        Mail::send('emails.author_without_books_librarian', ['authorsWithoutBooks' => $authorsWithoutBooks], function($message)        {            $message->to('librarian@awesomelibrary.com', 'The Librarian')->subject('Authors without Books! A check is required!');        });      }    }  }

注意:就像前面提过的,我们假定你已经了解了 Laravel 发送邮件的基本知识,没有的话可以到官网学习下相关知识。

到这里并没有结束。你可以在大量的案例和场景中使用 Laravel 的模型事件和模型观察者。举个例子,假设你写博客,你希望每次发布一篇新文章或者更新一篇原有文章的时候,都更新一些站点地图,这时就可以用到观察者。再比如,当添加新书的时候,记录一些东西,也可以用到观察者。

该篇属于专题:《 Laravel 的 Events(事件) 及 Observers(观察者)》

  • 下一篇:《 Laravel 的 Events 及 Observers(六) — 总结》
  • 上一篇:《 Laravel 的 Events 及 Observers(四) — 模型观察者》
Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
PHP and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values ​​and handle functions that may return null values.

How does PHP handle object cloning (clone keyword) and the __clone magic method?How does PHP handle object cloning (clone keyword) and the __clone magic method?Apr 17, 2025 am 12:24 AM

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP vs. Python: Use Cases and ApplicationsPHP vs. Python: Use Cases and ApplicationsApr 17, 2025 am 12:23 AM

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Will R.E.P.O. Have Crossplay?
1 months agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor