Access-Control-Allow-Origin

完整报错

Access to XMLHttpRequest at ‘http://xxx.xxx.xxx/api/ip’ from origin ‘null’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

解决（php）

单文件

如果不是用php框架，而是用原生写，在文件开头<?php之后加入header("Access-Control-Allow-Origin:*");就行了。

tp6

找到/tp5/app/BaseController.php这个文件，在初始化加下面这段就行了

// 初始化
protected function initialize()
{
    header("Access-Control-Allow-Origin:*");
    header("Access-Control-Allow-Methods:GET, POST, OPTIONS, DELETE");
    header("Access-Control-Allow-Headers:DNT,X-Mx-ReqToken,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type, Accept-Language, Origin, Accept-Encoding");
}

tp5

由于tp5没有默认应用文件，
所以找到tp5\application\index\controller文件夹，在里面创建一个PHP文件，加入下列代码

protected function initialize()
{
    //跨域
    parent::initialize(); // TODO: Change the autogenerated stub
    header('Access-Control-Allow-Origin:*');
    header('Access-Control-Allow-Methods:GET, POST, OPTIONS, DELETE, PUT');
    header('Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, token, Accept, x-access-sign, x-access-time');
}

然后，其他需要跨域文件extends创建的这个文件。

更暴力无脑的方法

找到tp5\public\index.php，加入

<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2019 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

// [ 应用入口文件 ]
namespace think;

require __DIR__ . '/../vendor/autoload.php';

// 解决跨域问题
header("Access-Control-Allow-Origin:*");
header("Access-Control-Allow-Methods:GET, POST, OPTIONS, DELETE");
header("Access-Control-Allow-Headers:DNT,X-Mx-ReqToken,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type, Accept-Language, Origin, Accept-Encoding");

// 执行HTTP应用并响应
$http = (new App())->http;

$response = $http->run();

$response->send();

$http->end($response);