Laravel 控制器中的訪問中間件

Question

我正在基於子域明智在laravel中創建一個貨幣轉換器中間件， app/Http/Middleware/Currency.php這個中間件用於轉換貨幣

namespace App\Http\Middleware;

use Closure;

class Currency
{
public function convert($request, Closure $next)
{
$sub=array_shift((explode('.', $_SERVER['HTTP_HOST'])));
$fromCurrency =  "AED";
$toCurrency = "$sub";
$amount = "1";
$url = "https://www.google.com/search?q=".$fromCurrency."+to+".$toCurrency;
$get = file_get_contents($url);
$data = preg_split('/\D\s(.*?)\s=\s/',$get);
$exhangeRate = (float) substr($data[1],0,7);
$convertedAmount = $amount*$exhangeRate;
$data = array( 'exhangeRate' => $exhangeRate, 'convertedAmount' =>$convertedAmount,       'fromCurrency' => strtoupper($fromCurrency), 'toCurrency' => strtoupper($toCurrency));
return json_encode( $data );
    }
}

並寫在Kernel.php 中

protected $middleware = [
     \App\Http\Middleware\Currency::class,
];

並顯示函數名稱在頁面中也必須是字符串錯誤，如何在控制器中訪問此返回值？

Answer 1

為了實現您的目的，您應該使用 Helper 而不是 Middleware。 根據 Laravel 文檔

中間件提供了一種方便的機制來過濾進入應用程序的 HTTP 請求。 例如，Laravel 包含一個中間件，用於驗證您的應用程序的用戶是否已通過身份驗證。 如果用戶未通過身份驗證，中間件會將用戶重定向到登錄屏幕。 但是，如果用戶通過了身份驗證，中間件將允許請求進一步進入應用程序。

您可以按如下方式創建自定義 Helper 並在您的應用程序中的任何位置使用它

第 1 步：創建您的 Currency Helpers 類文件並為其提供匹配的命名空間。 編寫您的類和方法：

  <?php // Code within app\Helpers\Currency.php

    namespace App\Helpers;


class Currency
{
    public static function convert($request, Closure $next)
    {
        $sub=array_shift((explode('.', $_SERVER['HTTP_HOST'])));
        $fromCurrency =  "AED";
        $toCurrency = "$sub";
        $amount = "1";
        $url = "https://www.google.com/search?q=".$fromCurrency."+to+".$toCurrency;
        $get = file_get_contents($url);
        $data = preg_split('/\D\s(.*?)\s=\s/',$get);
        $exhangeRate = (float) substr($data[1],0,7);
        $convertedAmount = $amount*$exhangeRate;
        $data = array( 'exhangeRate' => $exhangeRate, 'convertedAmount' =>$convertedAmount,       'fromCurrency' => strtoupper($fromCurrency), 'toCurrency' => strtoupper($toCurrency));
        return json_encode( $data );
    }
}

第 2 步：創建別名：

<?php // Code within config/app.php

    'aliases' => [
     ...
        'Currency' => App\Helpers\Helper::class,
     ...

第 3 步：在項目根目錄中運行composer dump-autoload

第 4 步：在控制器中像這樣使用它

<?php 

namespace App\Http\Controllers;

use Currency;



 class SomeController extends Controller
    {

        public function __construct()
        {
            Currency::convert($value);
        }

Answer 2

我不認為中間件是實現您想要的功能的最佳方式，而是使用中間件來完成您的要求，中間件本身必須有一個名為handle而不是convert的函數。 您也可以將結果閃存到您的會話中以在控制器內訪問它。

還要注意句柄函數的返回，因為它是進程繼續所必需的

namespace App\Http\Middleware;

use Closure;

class Currency
{
    public function handle($request, Closure $next)
    {
        $explodedArr = explode('.', $_SERVER['HTTP_HOST']);
        $sub = array_shift($explodedArr);
        $fromCurrency =  "AED";
        $toCurrency = "$sub";
        $amount = "1";
        $url = "https://www.google.com/search?q=".$fromCurrency."+to+".$toCurrency;
        $get = file_get_contents($url);
        $data = preg_split('/\D\s(.*?)\s=\s/',$get);
        $exhangeRate = (float) substr($data[1],0,7);
        $convertedAmount = $amount*$exhangeRate;
        $data = array( 'exhangeRate' => $exhangeRate, 'convertedAmount' =>$convertedAmount,       'fromCurrency' => strtoupper($fromCurrency), 'toCurrency' => strtoupper($toCurrency));

        session()->flash('convert_result', json_encode($data) );
        return $next($request);
    }
}

// and you should be able to get the result in your controller like so
session('convert_result');