初始化项目：添加后端代码、ThinkPHP框架、前端资源

application/middleware/CorsMiddleware.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace app\middleware;
+
+class CorsMiddleware
+{
+    public function handle($request, \Closure $next)
+    {
+        if ($request->isOptions()) {
+            $response = response();
+            $response->header('Access-Control-Allow-Origin', '*');
+            $response->header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
+            $response->header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
+            return $response;
+        }
+
+        return $next($request);
+    }
+}