我正在从 Tomcat 中运行的另一个程序调用 Node js 服务,当我使用下面的代码时一切都很好。
var express = require('express')
, routes = require('./routes')
, user = require('./routes/user')
, http = require('http')
, path = require('path'),
var app = express();
// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
// development only
if ('development' == app.get('env')) {
app.use(express.errorHandler());
}
app.get('/get', function (req, res) {
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', '*');
// 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);
res.send('Hello World!');
});
http.createServer(app).listen(app.get('port'), function(){
console.log('Express server listening on port ' + app.get('port'));
});
但是为了最小化代码,我向其中引入了中间件,如下所示,
var express = require('express')
, routes = require('./routes')
, user = require('./routes/user')
, http = require('http')
, path = require('path'),
var app = express();
var allowCrossDomain = function(req, res, next) {
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', '*');
// 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);
next();
}
// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(allowCrossDomain);
app.use(express.static(path.join(__dirname, 'public')));
// development only
if ('development' == app.get('env')) {
app.use(express.errorHandler());
}
app.get('/get', function (req, res) {
res.send('Hello World!');
});
http.createServer(app).listen(app.get('port'), function(){
console.log('Express server listening on port ' + app.get('port'));
});
此时我得到XMLHttpRequest无法加载http://localhost:3000/get 。请求的资源上不存在“Access-Control-Allow-Origin” header 。来源'http://localhost:8083 ' 因此不允许访问。,我不知道在哪里丢失了它。
最佳答案
这是我的解决方法,希望对你有帮助。
var express = require('express'),
routes = require('./routes'),
user = require('./routes/user'),
http = require('http'),
path = require('path'),
var app = express();
var allowCrossDomain = function(req, res, next) {
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', '*');
// 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);
next();
}
// all environments
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(allowCrossDomain);
app.use(express.static(path.join(__dirname, 'public')));
// development only
if ('development' == app.get('env')) {
app.use(express.errorHandler());
}
app.get('/get', function (req, res) {
res.end('Hello World!');
});
app.listen(3000,function(){
console.log("It's Started on PORT 3000");
});
关于javascript - XMLHttpRequest 无法加载 http ://localhost:3000/get,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28515351/