我试图在使用Express.js web框架的Node.js应用程序中支持CORS。我已经阅读了谷歌关于如何处理这个问题的小组讨论，并阅读了一些关于CORS如何工作的文章。首先，我这样做(代码是用CoffeeScript语法写的):
app.options "*", (req, res) ->
res.header 'Access-Control-Allow-Origin', '*'
res.header 'Access-Control-Allow-Credentials', true
# try: 'POST, GET, PUT, DELETE, OPTIONS'
res.header 'Access-Control-Allow-Methods', 'GET, OPTIONS'
# try: 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept'
res.header 'Access-Control-Allow-Headers', 'Content-Type'
# ...
这似乎不管用。似乎我的浏览器(Chrome)没有发送最初的选项请求。当我刚刚更新了块的资源，我需要提交一个跨起源GET请求:
app.get "/somethingelse", (req, res) ->
# ...
res.header 'Access-Control-Allow-Origin', '*'
res.header 'Access-Control-Allow-Credentials', true
res.header 'Access-Control-Allow-Methods', 'POST, GET, PUT, DELETE, OPTIONS'
res.header 'Access-Control-Allow-Headers', 'Content-Type'
# ...
它工作(在Chrome)。这也适用于Safari。
我听说……
在实现CORS的浏览器中，每个跨源GET或POST请求之前都有一个OPTIONS请求，用于检查GET或POST是否正常。
所以我的主要问题是，为什么这种情况在我身上没有发生?为什么我的app。options块没有被调用?为什么我需要在我的主app.get块设置标题?
我在我的server.js文件中使用了下面的方法。这里的关键部分是从请求头中获取起源，然后在服务器响应中允许它，此时我们可以设置将返回的头，包括如果找到匹配则允许的起源。
**const origin = req.headers.origin;**
let decoder = new StringDecoder('utf-8');
let buffer = '';
req.on('data', function (data) {
buffer += decoder.write(data);
});
req.on('end', function () {
buffer += decoder.end();
let chosenHandler = typeof (server.router[trimmedPath]) !== 'undefined' ? server.router[trimmedPath] : handlers.notFound;
const data = { ....data object vars}
// should be wrapped in try catch block
chosenHandler(data, function (statusCode, payload, contentType) {
server.processHandlerResponse(res, method, trimmedPath, statusCode, payload, contentType, **origin**);
server.processHandlerResponse = function (res, method, trimmedPath, statusCode, payload, contentType, origin) {
contentType = typeof (contentType) == 'string' ? contentType : 'json';
statusCode = typeof (statusCode) == 'number' ? statusCode : 200;
let payloadString = '';
if (contentType == 'json') {
res.setHeader('Content-Type', 'application/json');
const allowedOrigins = ['https://www.domain1.com', 'https://someotherdomain','https://yetanotherdomain',
...// as many as you need
];
**if (allowedOrigins.indexOf(origin) > -1) {
res.setHeader('Access-Control-Allow-Origin', origin);
}**
payload = typeof (payload) == 'object' ? payload : {};
payloadString = JSON.stringify(payload);
}
... // if (other content type) ...rinse and repeat..
我对Express 4.2.0的最简单的解决方案(编辑:在4.3.0中似乎不起作用)是:
function supportCrossOriginScript(req, res, next) {
res.status(200);
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "Content-Type");
// res.header("Access-Control-Allow-Headers", "Origin");
// res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
// res.header("Access-Control-Allow-Methods","POST, OPTIONS");
// res.header("Access-Control-Allow-Methods","POST, GET, OPTIONS, DELETE, PUT, HEAD");
// res.header("Access-Control-Max-Age","1728000");
next();
}
// Support CORS
app.options('/result', supportCrossOriginScript);
app.post('/result', supportCrossOriginScript, function(req, res) {
res.send('received');
// do stuff with req
});
我想做app.all('/result'，…)也可以…
