这是我使用express的简单nodejs应用程序:
const express = require('express');
const app = express();
const user = require('./routes/user').user;
const browser = require('./routes/browser');
const bodyParser = require('body-parser');
// CORS middleware
const allowCrossDomain = function(req, res, next) {
res.header('Access-Control-Allow-Origin', '*');
res.header('Access-Control-Allow-Methods', '*');
res.header('Access-Control-Allow-Headers', '*');
next();
}
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(allowCrossDomain);
app.use('/', user);
app.use('/', browser);
const port = process.env.PORT || 4001;
app.listen(port, function() {
console.log('Express server listening on port ' + port)
});
路由处理程序“浏览器”,我添加了中间件:
const express = require('express');
const router = express.Router();
router.use(function (req, res, next) {
console.log(req.body);
next();
});
router.post('/get-content', (req, res) => {
});
在这里,我得到了中间件的奇怪行为。我想获取请求正文数据,但在控制台中我看到空对象而不是预期的内容与内容。调用next()后中间件第二次触发,最后我得到请求体。在我的案例中帮助我理解中间件行为。
它可以帮助。安装cors包,并在express.use中提供。
中间件支持CORS飞行前请求
const allowCrossDomain = function(req, res, next) {
res.header('Access-Control-Allow-Origin', '*');
res.header('Access-Control-Allow-Methods', '*');
res.header('Access-Control-Allow-Headers', '*');
//intercepts OPTIONS method
if ('OPTIONS' === req.method) {
res.sendStatus(200);
} else {
next();
}
}