5个基本的CakePHP面试问题 *

最好的CakePHP开发人员和工程师可以回答的基本问题. 在我们社区的推动下，我们鼓励专家提交问题并提供反馈.

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Interview Questions

这个多模型验证规则有什么问题? 两个、一个还是两个都不执行?为什么? How might this code be fixed?

'email' => array(
    'rule' => array(
        'rule' => 'notEmpty',
        'message' => 'Email address is required.'
    ),
    'rule' => array(
        'rule' => 'email',
        'message' => 'The email address you entered is invalid.'
    )
)

View answer

The key 'rule' needs to be unique when calling multiple validation rules. In the case above, the notEmpty rule will never be called, as the email 规则将简单地覆盖它(因为多维数组具有相同的键).

Each key should be unique, e.g:

'email' => array(
    'rule-1' => array(
        'rule' => 'notEmpty',
        'message' => 'Email address is required.
    ),
    'rule-2' => array(
        'rule' => 'email',
        'message' => 'The email address you entered is invalid.'
    )
)

What is the purpose of $this->set(); when used in the Controller actions, e.g:

$this->set('articles', $articles);

同样，将上述代码行与以下代码行进行比较:

$this->set(compact('articles'));

各自的相对优势是什么? Which would you use and why?

View answer

The set() 方法用于在视图文件中创建变量. In the example above, the variable $articles 然后可以在视图模板文件中用于该操作吗.

An advantage of the first example (i.e., $this->set('articles', $articles); 它是否允许视图上的变量名与控制器上的变量名不同. 例如，如果你想让它们不同，你可以这样做 $this->set('articlesData', $articles);. 视图文件上的变量将是 $articlesData.

第二种方法的优点是.e., $this->set(compact('articles'));另一方面，它更整洁，也更不容易出错. It is also shorter and easier to write, 特别是在我们为视图设置几个变量的地方.

在下面的代码行中，如何能够 Containable behavior be used to optimize the find query so that only the region data is returned (i.e., without any model associations):

$this->Region->find('all');

View answer

The Containable behavior 允许开发人员指定从对象中检索哪些关联模型(如果有的话) find query.

因此，要确保在上面的示例中没有返回其他相关模型, it could simply be re-written as:

$this->Region->find('all', array('contain' => false));

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A current alternative to the Containable behavior is to use the recursive function. Why is the use of the recursive 下面的函数在我们只想检索区域数据而没有任何模型关联的情况下是不正确的?

$this->Region->find('all', array('recursive' => 0));

View answer

The use of recursive 是不正确的在上面的例子(如果我们不想拉任何相关的数据)，因为 recursive works as follows:

-1 —没有关联数据被检索到 find query.
` 0 – Retrieves any BelongsTo` associated data.
` 1 -检索任何直接相关的关联(例如.e., BelongsTo, HasMany, HasOne, HasAndBelongsToMany`).
' 2 ' -检索任何直接相关的关联，以及它们的关联的关联.

So in the above, example, 应该使用-1(而不是0)来避免提取任何相关数据.

It is also important to note that recursive 将在CakePHP 3中被淘汰，取而代之的是 Containable behavior.

组件、行为和Helper之间的区别是什么? 提供一个示例，说明在何处和何时可以使用每种方法.

View answer

这三个都是相似的，因为它们的作用是扩展现有的CakePHP功能, but the differ on what they extend:

A Component is used to extend a Controller
A Behavior is used to extend a Model
A Helper is used to extend a View.

For example:

A shopping cart Component 可能会提供可以在多个控制器之间使用和共享的功能.
A custom upload Behavior 可以用来扩展模型，例如添加图片上传. Another common example of a Behavior 是在CakePHP默认提供的功能之外添加额外的验证功能吗.
A Helper 可以用来辅助视图功能吗. A good example here would be the CK Editor helper that makes it easy to display a CK Editor.