节点 CORS 策略：请求的资源上不存在“Access-Control-Allow-Origin”header
[英]Node CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource
问题描述
I am using two server of port 8080 and 8082, where 8082 works on client side and 8080 acts as a middleware.
我正在使用端口 8080 和 8082 的两台服务器，其中 8082 在客户端工作，而 8080 作为中间件。 I am making a http callout from server to middleware using a html button, but it gives an error " Access to XMLHttpRequest at ' http://localhost:8080/ ' from origin ' http://localhost:8082 ' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. " I am making a http callout from server to middleware using a html button, but it gives an error " Access to XMLHttpRequest at ' http://localhost:8080/ ' from origin ' http://localhost:8082 ' has been blocked by CORS 策略：请求的资源上不存在“Access-Control-Allow-Origin”header。 ”
Attaching the code: Server.js附上代码： Server.js
var http = require('http');
var url = require('url');
var fs = require('fs');
var cors = require('cors');
var express = require('express');
var app = express();
app.use(cors());
var server = http.createServer(function(request, response,next) {
var path = url.parse(request.url).pathname;
switch (path) {
case '/':
response.writeHead(200, {
'Content-Type': 'text/plain'
});
response.write("This is Test Message.");
response.end();
break;
case '/server.html':
fs.readFile(__dirname + path, function(error, data) {
if (error) {
response.writeHead(404);
response.write(error);
response.end();
} else {
response.writeHead(200, {
'Content-Type': 'text/html'
});
response.write(data);
response.end();
}
});
break;
case '/HtmlPage2.html':
fs.readFile(__dirname + path, function(error, data) {
if (error) {
response.writeHead(404);
response.write(error);
response.end();
} else {
response.writeHead(200, {
'Content-Type': 'text/html'
});
response.write(data);
response.end();
}
});
break;
default:
response.writeHead(404);
response.write("opps this doesn't exist - 404");
response.end();
break;
}
});
server.listen(8082);
Server.html服务器.html
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="server.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
function callServer(){
$.get('http://localhost:8080', function(returnResult) {
});
}
</script>
</head>
<body>
<button onclick="callServer()">Click</button>
</body>
MiddleWareServer.js MiddleWareServer.js
var http = require('http');
var url = require('url');
var fs = require('fs');
var cors = require('cors');
var express = require('express');
var app = express();
app.use(cors());
var server = http.createServer(function(request, response,next) {
response.writeHead(200, {
'Content-Type': 'text/plain'
});
function returnResult(){
console.log('Called from the port:8082');
}
response.write("Port 8080 started..");
response.end();
});
server.listen(8080);
2 个解决方案
解决方案1
0 2019-11-05 19:51:30
That is not how you use express.这不是你使用快递的方式。
MiddleWareServer.js MiddleWareServer.js
var cors = require('cors');
var express = require('express');
var app = express();
app.use(cors());
app.get('/', function(request, response, next) {
response.send("Port 8080 started..");
})
express.listen(8080);
Sending a get request to localhost:8080 would return Port 8080 started.. .向localhost:8080发送 get 请求将返回Port 8080 started.. 。
Same goes for Server.js . Server.js也是如此。
解决方案2
0 已采纳 2019-11-07 06:34:18
Just used Express and it worked.. Replacing and posting new files: These file will fulfill the following features:刚刚使用 Express 并且它有效.. 替换和发布新文件：这些文件将实现以下功能：
- Create and start two different server.创建并启动两个不同的服务器。
- Call the middleware server from a html file from 8082 port.从 8082 端口的 html 文件调用中间件服务器。
- Fetch the response in html file from middle ware server.从中间件服务器获取 html 文件中的响应。
server.js服务器.js
const express = require('express');
const app = express();
const path = require('path');
const router = express.Router();
var cors = require('cors');
app.use(cors());
router.get('/server',function(req,res){
res.sendFile(path.join(__dirname+'/server.html'));
});
app.use('/', router);
app.listen(8082);
console.log('Running at Port 8082');
MiddleWareServer.js MiddleWareServer.js
const express = require('express');
const app = express();
var cors = require('cors');
app.use(cors());
app.get('/', (req, res) => res.send('Localhost:8080 has been Started'));
app.post('/middlewarehit', function(req,res){
res.end('Localhost:8080 Hit');
}
);
app.listen(8080);
console.log('Running at Port 8080');
server.html服务器.html
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
function callServer(){
$.ajax({
url: "http://localhost:8080/middlewarehit",
type: "POST",
dataType: '',
success: function(res){
$('#response').val(res);
}
});
}
</script>
</head>
<body>
<input type="text" id="response">
<button onclick="callServer()">Click</button>
</body>
</html>
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