项目A通过Ajax访问项目B的接口,获取json数据,项目B采用Node+Express技术栈。项目A可能遇到跨域访问控制问题。
报错如下:
XMLHttpRequest cannot load http://127.0.0.1:3000/news/latest. No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘http://localhost:8080’ is therefore not allowed access.
方案:解决代码如下:
var express = require('express');
var app = express();
//设置跨域访问
app.all('*', function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "X-Requested-With");
res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
res.header("X-Powered-By",' 3.2.1')
res.header("Content-Type", "application/json;charset=utf-8");
next();
});
app.use('/', index);
app.listen(3000);
console.log('Listening on port 3000...');
其他:
Access-Control-Allow-Origin
浏览器的确发出了请求,只有当目标页面的response中,包含了 Access-Control-Allow-Origin 这个header,并且它的值里有我们自己的域名时,浏览器才允许我们拿到它页面的数据进行下一步处理。