Create validate config middleware

src/Http/Middleware/ValidateConfigMiddleware.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Bryceandy\Laravel_Pesapal\Http\Middleware;
+
+use Bryceandy\Laravel_Pesapal\Exceptions\ConfigurationUnavailableException;
+use Closure;
+
+class ValidateConfigMiddleware
+{
+    /**
+     * Ensures pesapal configurations are always available
+     * @param $request
+     * @param Closure $next
+     * @return mixed
+     * @throws ConfigurationUnavailableException
+     */
+    public function handle($request, Closure $next)
+    {
+        if (!config('pesapal.consumer_key') ||
+            !config('pesapal.consumer_secret') ||
+            !config('pesapal.callback_url'))
+            throw new ConfigurationUnavailableException();
+
+        return $next($request);
+    }
+}