自动注入的 Laravel 模型没有属性

问题描述

我是 Laravel 的新手.我已经为我的一个表创建了一个模型、一个资源控制器和一个路由，我修改了模型类以使用特定的表名，但是 Laravel 5.4 注入的模型对象没有属性，即使相应的记录存在于数据库.这是我采取的步骤.

I'm new to Laravel. I have created a model, a resource controller, and a route for one of my tables, I have modified the model class to use a particular table name, but the model object injected by Laravel 5.4 has no attributes even though a corresponding record exists in the database. Here are the steps I took.

1) 使用工匠创建模型.我运行了这个命令:

1) Create the model with artisan. I ran this command:

php artisan make:model Tree

2) 将 Tree 模型类修改为 instructed 以指定特定表.我必须这样做，因为我的表被命名为 tree，而不是 Laravel 根据其内部规则假设的树".

2) Modify the Tree model class as instructed to specify a specific table. I had to do this because my table is named tree, not the "trees" as Laravel would otherwise assume based on its internal rules.

/**
 * The table associated with the model.
 *
 * @var string
 */
protected $table = 'tree';

3) 创建一个资源控制器，通过这个命令使用我的模型

3) Create a resource controller that makes use of my model with this command

php artisan make:controller CategoryController --resource --model=Tree

4) 添加资源路由 routes/web.php 以将 Web 服务器路径映射到控制器:

4) Add a resource route routes/web.php in order to map a web server path onto the controller:

Route::resource('categories', 'CategoryController');

5) 修改 CategoryController 的 show() 方法，以 var_dump 注入的 $tree 对象.它看起来像这样:

5) Modify the show() method of the CategoryController to var_dump the injected $tree object. It looks like this:

/**
 * Display the specified resource.
 *
 * @param  AppTree  $tree
 * @return IlluminateHttpResponse
 */
public function show(Tree $tree)
{
    // we need to display the children of $tree
    var_dump($tree);

}

6) 我的表结构遵循 Laravel 文档指定的所有约定.有一个整数 id 列是无符号的 &自动递增.我有 created_at 和 updated_at 时间戳.唯一不同的是表名是树"而不是树"，但这应该包含在我上面所做的更改中:

6) My table structure follows all the conventions specified by Laravel docs. There is an integer id column that is unsigned & auto-incrementing. I have the created_at and updated_at timestamps. The only thing different is that the table name is "tree" and not "trees", but that should be covered with the change I made above:

CREATE TABLE IF NOT EXISTS `tree` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `parent_id` int(10) unsigned DEFAULT NULL,
  `label` varchar(64) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `display_order` int(11) unsigned NOT NULL DEFAULT '0',
  `forum_id` int(5) NOT NULL DEFAULT '0',
  `url` varchar(128) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `flavor` tinyint(4) NOT NULL DEFAULT '0',
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `parent_pkey` (`parent_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

此表包含数据.它绝对有一个 id=1 的记录.

This table contains data. It most definitely has a record with id=1.

7) 我访问了应该激活我的资源控制器的 show() 方法的 url.我得到的输出证实这实际上是 CategoryController::show() 方法.http://example.com/categories/1

7) I visit the url which should activate the show() method of my resource controller. The output I get verfies that this is in fact the method CategoryController::show(). http://example.com/categories/1

问题来了.

var_dump($tree) 的输出没有属性.没有错误，但注入的对象有问题.

object(AppTree)#217 (24) {
  ["table":protected]=>
  string(4) "tree"
  ["connection":protected]=>
  NULL
  ["primaryKey":protected]=>
  string(2) "id"
  ["keyType":protected]=>
  string(3) "int"
  ["incrementing"]=>
  bool(true)
  ["with":protected]=>
  array(0) {
  }
  ["perPage":protected]=>
  int(15)
  ["exists"]=>
  bool(false)
  ["wasRecentlyCreated"]=>
  bool(false)
  ["attributes":protected]=>
  array(0) {
  }
  ["original":protected]=>
  array(0) {
  }
  ["casts":protected]=>
  array(0) {
  }
  ["dates":protected]=>
  array(0) {
  }
  ["dateFormat":protected]=>
  NULL
  ["appends":protected]=>
  array(0) {
  }
  ["events":protected]=>
  array(0) {
  }
  ["observables":protected]=>
  array(0) {
  }
  ["relations":protected]=>
  array(0) {
  }
  ["touches":protected]=>
  array(0) {
  }
  ["timestamps"]=>
  bool(true)
  ["hidden":protected]=>
  array(0) {
  }
  ["visible":protected]=>
  array(0) {
  }
  ["fillable":protected]=>
  array(0) {
  }
  ["guarded":protected]=>
  array(1) {
    [0]=>
    string(1) "*"
  }
}

我做错了吗?如何让 Laravel 注入正​​确的对象?

有人问我为什么在我的路线中注入了错误的对象.这是在步骤 #3 中自动生成的类的缩写版本.它清楚地引用了 Tree 类和它期望一个树对象的代码提示.除了 var_dump 语句之外，我没有创建任何这些代码.它都是按照文档的指示由工匠命令自动生成的.

Someone asked why I was injecting the wrong object in my route. Here is an abbreviated version of the class that was auto-generated in step #3. It clear references the Tree class and code-hints it is expecting a tree object. I did not create any of this code except the var_dump statement. It was all auto-generated by artisan commands expressly as instructed by the docs.

namespace AppHttpControllers;

use AppTree;
use IlluminateHttpRequest;

class CategoryController extends Controller
{

    /**
     * Display the specified resource.
     *
     * @param  AppTree  $tree
     * @return IlluminateHttpResponse
     */
    public function show(Tree $tree)
    {
        // we need to display the children of $tree
        var_dump($tree);

    }

}

推荐答案

Route Model 绑定有一个命名约定.

There is a naming convention on Route Model binding.

尝试将操作调用更改为:

Try to change the action call to this:

public function show(Tree $category)
{
    var_dump($category);
}

更新:我查看了源代码，您也可以更改资源路由声明中的参数名称:

Update: I looked in the source and you can also change the parameters name in resource Route declaration:

Route::resource('categories', 'CategoryController', ['parameters'=>['categories'=>'tree']]);

并在动作调用中使用 $tree 变量

And use the $tree variable in action call

public function show(Tree $tree)

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