Node-③ koa 框架搭建的后台中如何允许前端进行跨域请求

1.遇到跨域阻止ERR 时
   Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
   from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

1. 在后台的app.js（或者你自己命名的入口文件如server.js等）中，添加一个允许跨域请求头的设置即可 

// 设置跨域

app.use(async (ctx, next) => {

  ctx.set('Access-Control-Allow-Origin', '*');

  await next();

});

方案二：争对传参的设置

app.use(async (ctx, next) => {

  ctx.set('Access-Control-Allow-Origin', '*');

  ctx.set('Access-Control-Allow-Headers', 'X-Requested-With,Content-Type');

  ctx.set('Access-Control-Allow-Methods', 'PUT,POST,GET,DELETE,OPTIONS');

  await next();

});

 

2. 前端设置请求模式为跨域。

   

function TryLogin() {

this.axios.post(`http://10.244.4.4:3001/FixedAssetsManagement/Api/RegisteredAccount`, " ", {

mode: "cors",

headers: {

'Accept': 'application/json,text/plain,*/*'

}

}).then(function(response) {

console.log(response);

const data = response.data;

}, function(response) {});

}
参考连接：https://blog.csdn.net/qq_35059678/article/details/95378859