我正在http://localhost:4200上运行Angular 4（angular.io/angular cli）应用以及http://localhost:3000上的ExpressJS应用
我在这个问题上花了好几个小时，我找到了一个解决方案，即使用chrome扩展来禁用CORS。
我试图在ExpressJS应用程序中自己添加CORS的中间件头文件，因为我读过这只是服务器端问题而不是客户端问题，因此它不是角度问题。
我试图添加cors npm模块。那也行不通。
我故意在我的路线和路线之前添加了cors线路。 app.js中的静态文件夹定义。
我不知道问题是什么..
无法加载http://localhost:3000/users/post：对预检的响应 请求未通过访问控制检查：否 请求中存在“Access-Control-Allow-Origin”标头 资源。因此不允许来源“http://localhost:4200” 访问。
OPTIONS /users/post 200 1.206 ms - 13
200怎么样？为什么它认为没关系？
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var app = express();
// Add headers
/*
app.use(function (req, res, next) {
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', 'http://localhost:4200');
// Request methods you wish to allow
res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
// Request headers you wish to allow
res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
// Set to true if you need the website to include cookies in the requests sent
// to the API (e.g. in case you use sessions)
res.setHeader('Access-Control-Allow-Credentials', true);
// Pass to next layer of middleware
next();
});
*/
/*var corsOptions = {
origin: ['http://localhost:4200'],
optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
};
const corsOptions = {
origin: '*',
method: ['GET', 'POST'],
//allowedHeaders: ['Content-Type', 'Authorization', 'Origin', 'Accept', 'X-Requested-With'],
optionsSuccessStatus: 200 //Some legacy browsers (IE11, various SmartTVs) choke on 204
};
app.use(cors(corsOptions));
app.options('*', cors());
*/
const corsOptions = {
origin: 'http://localhost:4200',
method: ['GET', 'POST'],
//allowedHeaders: ['Content-Type', 'Authorization', 'Origin', 'Accept', 'X-Requested-With'],
optionsSuccessStatus: 200 //Some legacy browsers (IE11, various SmartTVs) choke on 204,
credentials: true
};
app.use(cors(corsOptions));
var index = require('./routes/index');
var users = require('./routes/users');
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: false}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', index);
app.use('/users', users);
// catch 404 and forward to error handler
app.use(function (req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
// error handler
app.use(function (err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
var express = require('express');
var router = express.Router();
var conn = require('../connect')();
//var cors = require('cors');
var table = "users";
router.get('/', (req, res, next) => {
var query = `SELECT * FROM ${table}`;
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
router.post('/post', (req, res) => {
//console.log("Body: ", req.body);
/**
* Test Case:
* {"user":{"name": "jack","email": "jack@gmail.com","password": "jackPass"}}
* */
var name = req.body.name;
var email = req.body.email;
var password = req.body.password;
var query = `INSERT INTO ${table} VALUES (null, "${name}", "${email}", "${password}")`;
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
router.get('/:search/', (req, res, next) => {
var search = req.params.search;
var query = "";
if (isNaN(search)) {
query = `SELECT * FROM ${table} WHERE name LIKE '%${search}%'`;
} else {
query = `SELECT * FROM ${table} WHERE id='${search}'`;
}
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
module.exports = router;
var express = require('express');
var router = express.Router();
var conn = require('../connect')();
//var cors = require('cors');
var table = "users";
router.get('/', (req, res, next) => {
var query = `SELECT * FROM ${table}`;
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
router.post('/post', (req, res) => {
//console.log("Body: ", req.body);
/**
* Test Case:
* {"user":{"name": "jack","email": "jack@gmail.com","password": "jackPass"}}
* */
var name = req.body.name;
var email = req.body.email;
var password = req.body.password;
var query = `INSERT INTO ${table} VALUES (null, "${name}", "${email}", "${password}")`;
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
router.get('/:search/', (req, res, next) => {
var search = req.params.search;
var query = "";
if (isNaN(search)) {
query = `SELECT * FROM ${table} WHERE name LIKE '%${search}%'`;
} else {
query = `SELECT * FROM ${table} WHERE id='${search}'`;
}
console.log(query);
conn.query(query, (err, result, fields) => {
if (err) throw err;
res.send(result);
});
});
module.exports = router;
答案 0 :(得分：2)
在您的快递app.js
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
next();
//rest of your app.get/post/whatevers
这应该为你提供角色。