php Laravel：在失败时处理 findOrFail()
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Laravel : Handle findOrFail( ) on Fail
提问by cjmling
I am looking for something which can be like findOrDo(). Like do this when data not found. Something could be like
我正在寻找类似于 findOrDo() 的东西。像在找不到数据时这样做。事情可能像
Model::findOrDo($id,function(){
return "Data not found";
});
Is there any similar thing in laravel that I can do this elegantly and beautifully ?
Laravel 中是否有类似的东西可以让我优雅而漂亮地做到这一点？
*I tried googling but could not find one
*我尝试谷歌搜索但找不到
回答by Meisam Mulla
use Illuminate\Database\Eloquent\ModelNotFoundException;
// Will return a ModelNotFoundException if no user with that id
try
{
$user = User::findOrFail($id);
}
// catch(Exception $e) catch any exception
catch(ModelNotFoundException $e)
{
dd(get_class_methods($e)); // lists all available methods for exception object
dd($e);
}
回答by Pitchinnate
Another option is to modify the default Laravel Exception Handler, found in app/Exceptions/Handler.php on the render()function I made this change:
另一种选择是修改默认的 Laravel 异常处理程序，在 app/Exceptions/Handler.php 中找到render()我进行此更改的函数：
public function render($request, Exception $e)
{
if(get_class($e) == "Illuminate\Database\Eloquent\ModelNotFoundException") {
return (new Response('Model not found', 400));
}
return parent::render($request, $e);
}
That way instead of getting a 500, I send back a 400 with a custom message without having to do a try catch on every single findOrFail()
这样我就不会得到 500，而是用自定义消息发回 400，而不必对每个消息都进行尝试 findOrFail()
回答by thewizardguy
An alternative process could be to evaluate a collection instead. So,
替代过程可能是评估集合。所以，
$modelCollection = Model::where('id', $id)->get();
if(!$modelCollection->isEmpty()) {
doActions();
}
I agree it isn't as elegant, a one-liner or as case specific as you or I might like, but aside from writing a try catch statement every time, it's a nice alternative.
我同意它不像您或我可能喜欢的那样优雅、单行或特定于案例，但除了每次编写 try catch 语句之外，它还是一个不错的选择。
回答by lasec0203
as of Laravel v5.7, you can do this (the retrieving single modelvariation of @thewizardguyanswer)
从 Laravel v5.7 开始，您可以执行此操作（@thewizardguy答案的检索单个模型变体）
// $model will be null if not found
$model = Model::where('id', $id)->first();
if($model) {
doActions();
}
回答by Josh D.
By default, when you use an Eloquent model's findOrFailin a Laravel 5 application and it fails, it returns the following error:
默认情况下，当您findOrFail在 Laravel 5 应用程序中使用 Eloquent模型并失败时，它会返回以下错误：
ModelNotFoundException in Builder.php line 129:
'No query results for model [App\Model]'.
So to catch the exception and display a custom 404 page with your error message like "Ooops"....
因此，要捕获异常并显示带有错误消息的自定义 404 页面，例如“Ooops”....
Open up the app/Exceptions/Handler.phpfile, and add the code shown below to the top of the render function:
打开app/Exceptions/Handler.php文件，将下面显示的代码添加到渲染函数的顶部：
public function render($request, Exception $e)
{
if ($e instanceof \Illuminate\Database\Eloquent\ModelNotFoundException)
{
abort(404, 'Oops...Not found!');
}
return parent::render($request, $e);
}
来源：https: //selftaughtcoders.com/from-idea-to-launch/lesson-16/laravel-5-findorfail-modelnotfoundexception-show-404-error-page/
回答by Romeo Sierra
A little later for the party, from laravel 5.4 onward, Eloquent Builder supports macros. So, I would write a macro (in a separate provider) like follows.
晚一点的聚会，从 laravel 5.4 开始，Eloquent Builder 支持宏。所以，我会写一个宏（在一个单独的提供者中），如下所示。
Builder::macro('firstOrElse', function($callback) {
$res = $this->get();
if($res->isEmpty()) {
$callback->call($this);
}
return $res->first();
});
I can then do a retrieval as follows.
然后我可以按如下方式进行检索。
$firstMatchingStudent = DB::table('students')->where('name', $name)
->firstOrElse(function() use ($name) {
throw new ModelNotFoundException("No student was found by the name $name");
});
This will assign the first object of the result set if it is not empty, otherwise will adapt the behaviour I pass into the macro as a closure (throw Illuminate\Database\Eloquent\ModelNotFoundExceptionin this case).
如果结果集不为空，这将分配结果集的第一个对象，否则将调整我作为闭包传递给宏的行为（Illuminate\Database\Eloquent\ModelNotFoundException在这种情况下抛出）。
For the case of a model also this would work, except that models always return the builder instance.
对于模型的情况，这也可以工作，除了模型总是返回 builder instance。
