Origin <origin> is not allowed by Access-Control-Allow-Origin
Javascriptnode.jsAjaxGoogle ChromeCorsJavascript Problem Overview
XMLHttpRequest cannot load http://localhost:8080/api/test. Origin http://localhost:3000 is not allowed by Access-Control-Allow-Origin.
I read about cross domain ajax requests, and understand the underlying security issue. In my case, 2 servers are running locally, and like to enable cross domain requests during testing.
localhost:8080 - Google Appengine dev server
localhost:3000 - Node.js server
I am issuing an ajax request to localhost:8080 - GAE server
while my page is loaded from node server. What is the easiest, and safest ( Don't want to start chrome with disable-web-security
option). If I have to change 'Content-Type'
, should I do it at node server? How?
Javascript Solutions
Solution 1 - Javascript
Since they are running on different ports, they are different JavaScript origin
. It doesn't matter that they are on the same machine/hostname.
You need to enable CORS on the server (localhost:8080). Check out this site: http://enable-cors.org/
All you need to do is add an HTTP header to the server:
Access-Control-Allow-Origin: http://localhost:3000
Or, for simplicity:
Access-Control-Allow-Origin: *
Thought don't use "*" if your server is trying to set cookie and you use withCredentials = true
> when responding to a credentialed request, server must specify a domain, and cannot use wild carding.
Solution 2 - Javascript
If you need a quick work around in Chrome for ajax requests, this chrome plugin automatically allows you to access any site from any source by adding the proper response header
Solution 3 - Javascript
You have to enable CORS to solve this
if your app is created with simple node.js
set it in your response headers like
var http = require('http');
http.createServer(function (request, response) {
response.writeHead(200, {
'Content-Type': 'text/plain',
'Access-Control-Allow-Origin' : '*',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE'
});
response.end('Hello World\n');
}).listen(3000);
if your app is created with express framework
use a CORS middleware like
var allowCrossDomain = function(req, res, next) {
res.header('Access-Control-Allow-Origin', "*");
res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
res.header('Access-Control-Allow-Headers', 'Content-Type');
next();
}
and apply via
app.configure(function() {
app.use(allowCrossDomain);
//some other code
});
Here are two reference links
- how-to-allow-cors-in-express-nodejs
- diving-into-node-js-very-first-app #see the Ajax section
Solution 4 - Javascript
I accept @Rocket hazmat's answer as it lead me to the solution. It was indeed on the GAE server I needed to set the header. I had to set these
"Access-Control-Allow-Origin" -> "*"
"Access-Control-Allow-Headers" -> "Origin, X-Requested-With, Content-Type, Accept"
setting only "Access-Control-Allow-Origin"
gave error
Request header field X-Requested-With is not allowed by Access-Control-Allow-Headers.
Also, if auth token needs to be sent, add this too
"Access-Control-Allow-Credentials" -> "true"
Also, at client, set withCredentials
this causes 2 requests to sent to the server, one with OPTIONS
. Auth cookie is not send with it, hence need to treat outside auth.
Solution 5 - Javascript
In router.js just add code before calling get/post methods. It works for me without errors.
//Importing modules @Brahmmeswar
const express = require('express');
const router = express.Router();
const Contact = require('../models/contacts');
router.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();
});
Solution 6 - Javascript
If you are using express, you can use cors middleware as follows:
var express = require('express')
var cors = require('cors')
var app = express()
app.use(cors())
Solution 7 - Javascript
I was facing a problem while calling cross origin resource using ajax from chrome.
I have used node js and local http server to deploy my node js app.
I was getting error response, when I access cross origin resource
I found one solution on that ,
-
I have added below code to my app.js file
res.header("Access-Control-Allow-Origin", "*"); res.header("Access-Control-Allow-Headers", "X-Requested-With");
-
In my html page called cross origin resource using
$.getJSON();
$.getJSON("http://localhost:3000/users";, function (data) { alert("Success**"); var response=JSON.stringify(data); alert("success="+response); document.getElementById("employeeDetails").value=response; });
Solution 8 - Javascript
Add this to your NodeJS Server below imports:
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();
});
Solution 9 - Javascript
If you got 403 after that please reduce filters in WEB.XML tomcat config to the following:
<filter>
<filter-name>CorsFilter</filter-name>
<filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
<init-param>
<param-name>cors.allowed.origins</param-name>
<param-value>*</param-value>
</init-param>
<init-param>
<param-name>cors.allowed.methods</param-name>
<param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
</init-param>
<init-param>
<param-name>cors.allowed.headers</param-name>
<param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
</init-param>
<init-param>
<param-name>cors.exposed.headers</param-name>
<param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
</init-param>
</filter>
Solution 10 - Javascript
In case anyone searching for the solution , if you are using express here is the quick solution .
const express = require('express')
const cors = require('cors')
const app = express()
-
install cors using npm
npm install cors --save
-
import it [require ]
const cors = require('cors')
-
use it as middleware
app.use(cors())
for details insatll and usage of cors . That is it, hopefully it works.
Solution 11 - Javascript
I finally got the answer for apache Tomcat8
You have to edit the tomcat web.xml file.
probabily it will be inside webapps folder,
sudo gedit /opt/tomcat/webapps/your_directory/WEB-INF/web.xml
find it and edit it
<web-app>
<filter>
<filter-name>CorsFilter</filter-name>
<filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
<init-param>
<param-name>cors.allowed.origins</param-name>
<param-value>*</param-value>
</init-param>
<init-param>
<param-name>cors.allowed.methods</param-name>
<param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
</init-param>
<init-param>
<param-name>cors.allowed.headers</param-name>
<param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
</init-param>
<init-param>
<param-name>cors.exposed.headers</param-name>
<param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
</init-param>
<init-param>
<param-name>cors.support.credentials</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>cors.preflight.maxage</param-name>
<param-value>10</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CorsFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
This will allow Access-Control-Allow-Origin all hosts. If you need to change it from all hosts to only your host you can edit the
<param-name>cors.allowed.origins</param-name>
<param-value>http://localhost:3000</param-value>
above code from * to your http://your_public_IP or http://www.example.com
you can refer here Tomcat filter documentation
Thanks
Solution 12 - Javascript
For PHP, use this to set headers.
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: PUT, GET, POST");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");
Solution 13 - Javascript
Hi This is the way to solve CORS problem in node Just add these lines on server "api" side in Node.js(or what ever your server File), befor that make sure to install "cors"
const express = require('express');
const app = express();
app.use(express.json());
var cors = require('cors');
app.use(cors());
Solution 14 - Javascript
router.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "*");
res.header("Access-Control-Allow-Headers", "*");
next();});
add this to your routes which you are calling from front-end. Ex- if you call for http://localhost:3000/users/register you must add this code fragment on your back-end .js file which this route lays.
Solution 15 - Javascript
use dataType: 'jsonp', works for me.
async function get_ajax_data(){
var _reprojected_lat_lng = await $.ajax({
type: 'GET',
dataType: 'jsonp',
data: {},
url: _reprojection_url,
error: function (jqXHR, textStatus, errorThrown) {
console.log(jqXHR)
},
success: function (data) {
console.log(data);
// note: data is already json type, you just specify dataType: jsonp
return data;
}
});
} // function
Solution 16 - Javascript
If you are using express,
var express = require('express')
var cors = require('cors')
var app = express()
app.use(cors())
If you are using app.use(express.json());
code line in your server file to parse incoming requests with JSON payloads and is based on body-parser, keep in mind to use it after using app.use(cors())
code line. Otherwise, security issues may occur.
CORS
Solution 17 - Javascript
If your server is server=express()
just add server.use(cors())
to next line. For Example:
server.js
const express = require('express')
const cors = require('cors')
server=express()
server.use(cors())
server.get('/',(req,res)=>{
res.send({"name":"aakash","name2":"aakash4dev"})
})
server.listen(3000)
index.html
<script>
fetch('http://localhost:3005/')
.then(res=> res.json())
.then(data => console.log(data))
</script>
Solution 18 - Javascript
If you're in Google Chrome, try installing this add-on: