場景：手頭的項目需要對外提供API服務，需要對請求數據進行簽名校驗。提交接口的數據會有‘‘空字符值存在，laravel的Illuminate\Foundation\Http\Request接收到參數後，會將空字符強制轉換為NULL,導致簽名校驗通不過。

經過一番努力，找到幕後黑手。
Illuminate/Foundation/Http組件中有定義這個中間件。
vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ConvertEmptyStringsToNull.php

<?php

namespace Illuminate\Foundation\Http\Middleware;

class ConvertEmptyStringsToNull extends TransformsRequest
{
    /**
     * Transform the given value.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function transform($key, $value)
    {
        return is_string($value) && $value === ‘‘ ? null : $value;
    }
}
 

解決方法：
既然是中間件作祟，肯定在內核中有註冊。找到內核註釋該中間件就好。
app/Http/Kernel.php

class Kernel extends HttpKernel
{
    /**
     * The application‘s global HTTP middleware stack.
     *
     * These middleware are run during every request to your application.
     *
     * @var array
     */
    protected $middleware = [
        \App\Http\Middleware\CheckForMaintenanceMode::class,
        \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
        \App\Http\Middleware\TrimStrings::class,
        //\Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,//會將‘‘轉化為null
        \App\Http\Middleware\TrustProxies::class,
        \Illuminate\Session\Middleware\StartSession::class,
    ];
 

laravel踩坑記:空字符轉null