How can I set response header on express.js assets
Javascriptnode.jsExpressJavascript Problem Overview
I need to set CORS to be enabled on scripts served by express. How can I set the headers in these returned responses for public/assets?
Javascript Solutions
Solution 1 - Javascript
There is at least one middleware on npm for handling CORS in Express: cors. [see @mscdex answer]
This is how to set custom response headers, from the ExpressJS DOC
res.set(field, [value])
Set header field to value
res.set('Content-Type', 'text/plain');
or pass an object to set multiple fields at once.
res.set({
'Content-Type': 'text/plain',
'Content-Length': '123',
'ETag': '12345'
})
Aliased as
res.header(field, [value])
Solution 2 - Javascript
This is so annoying.
Okay if anyone is still having issues or just doesn't want to add another library. All you have to do is place this middle ware line of code before your routes.
>Cors Example
app.use((req, res, next) => {
res.append('Access-Control-Allow-Origin', ['*']);
res.append('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
res.append('Access-Control-Allow-Headers', 'Content-Type');
next();
});
// Express routes
app.get('/api/examples', (req, res)=> {...});
Solution 3 - Javascript
You can do this by using cors. cors will handle your CORS response
var cors = require('cors')
app.use(cors());
Solution 4 - Javascript
Short Answer:
-
res.setHeaders
- calls the native Node.js method -
res.set
- sets headers -
res.headers
- an alias to res.set
Solution 5 - Javascript
@klode's answer is right.
However, you are supposed to set another response header to make your header accessible to others.
Example:
First, you add 'page-size' in response header
response.set('page-size', 20);
Then, all you need to do is expose your header
response.set('Access-Control-Expose-Headers', 'page-size')
Solution 6 - Javascript
There is at least one middleware on npm for handling CORS in Express: cors.
Solution 7 - Javascript
You can also add a middleware to add CORS headers, something like this would work:
/**
* Adds CORS headers to the response
*
* {@link https://en.wikipedia.org/wiki/Cross-origin_resource_sharing}
* {@link http://expressjs.com/en/4x/api.html#res.set}
* @param {object} request the Request object
* @param {object} response the Response object
* @param {function} next function to continue execution
* @returns {void}
* @example
* <code>
* const express = require('express');
* const corsHeaders = require('./middleware/cors-headers');
*
* const app = express();
* app.use(corsHeaders);
* </code>
*/
module.exports = (request, response, next) => {
// http://expressjs.com/en/4x/api.html#res.set
response.set({
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Methods': 'DELETE,GET,PATCH,POST,PUT',
'Access-Control-Allow-Headers': 'Content-Type,Authorization'
});
// intercept OPTIONS method
if(request.method === 'OPTIONS') {
response.send(200);
} else {
next();
}
};
Solution 8 - Javascript
service.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization");
next();
});
Solution 9 - Javascript
First add 'field' in response header
response.set('field', 'value');
Then you need to do is expose your header
response.set('Access-Control-Expose-Headers', 'field')