Fetch API with Cookie

Question

I am trying out the new Fetch API but is having trouble with Cookies. Specifically, after a successful login, there is a Cookie header in future requests, but Fetch seems to ignore that headers, and all my requests made with Fetch is unauthorized.

Is it because Fetch is still not ready or Fetch does not work with Cookies?

I build my app with Webpack. I also use Fetch in React Native, which does not have the same issue.

Answer 1

Fetch does not use cookie by default. To enable cookie, do this:

fetch(url, {
  credentials: "same-origin"
}).then(...).catch(...);

Answer 2

In addition to @Khanetor's answer, for those who are working with cross-origin requests: credentials: 'include'

Sample JSON fetch request:

fetch(url, {
  method: 'GET',
  credentials: 'include'
})
  .then((response) => response.json())
  .then((json) => {
    console.log('Gotcha');
  }).catch((err) => {
    console.log(err);
});

https://developer.mozilla.org/en-US/docs/Web/API/Request/credentials

Answer 3

Have just solved. Just two f. days of brutforce

For me the secret was in following:

1. I called POST /api/auth and see that cookies were successfully received.

2. Then calling GET /api/users/ with credentials: 'include' and got 401 unauth, because of no cookies were sent with the request.

The KEY is to set credentials: 'include' for the first /api/auth call too.

Answer 4

If you are reading this in 2019, credentials: "same-origin" is the default value.

fetch(url).then

Answer 5

Programmatically overwriting Cookie header in browser side won't work.

In fetch documentation, Note that some names are forbidden. is mentioned. And Cookie happens to be one of the forbidden header names, which cannot be modified programmatically. Take the following code for example:

• Executed in the Chrome DevTools console of page https://httpbin.org/, Cookie: 'xxx=yyy' will be ignored, and the browser will always send the value of document.cookie as the cookie if there is one.
• If executed on a different origin, no cookie is sent.

fetch('https://httpbin.org/cookies', {
  headers: {
    Cookie: 'xxx=yyy'
  }
}).then(response => response.json())
.then(data => console.log(JSON.stringify(data, null, 2)));

P.S. You can create a sample cookie foo=bar by opening https://httpbin.org/cookies/set/foo/bar in the chrome browser.

See Forbidden header name for details.

Answer 6

Just adding to the correct answers here for .net webapi2 users.

If you are using cors because your client site is served from a different address as your webapi then you need to also include SupportsCredentials=true on the server side configuration.

        // Access-Control-Allow-Origin
        // https://learn.microsoft.com/en-us/aspnet/web-api/overview/security/enabling-cross-origin-requests-in-web-api
        var cors = new EnableCorsAttribute(Settings.CORSSites,"*", "*");
        cors.SupportsCredentials = true;
        config.EnableCors(cors);

Answer 7

This works for me:

import Cookies from 'universal-cookie';
const cookies = new Cookies();

function headers(set_cookie=false) {
  let headers = {
    'Accept':       'application/json',
    'Content-Type': 'application/json',
    'X-CSRF-Token': $('meta[name="csrf-token"]').attr('content')
};
if (set_cookie) {
    headers['Authorization'] = "Bearer " + cookies.get('remember_user_token');
}
return headers;
}

Then build your call:

export function fetchTests(user_id) {
  return function (dispatch) {
   let data = {
    method:      'POST',
    credentials: 'same-origin',
    mode:        'same-origin',
    body:        JSON.stringify({
                     user_id: user_id
                }),
    headers:     headers(true)
   };
   return fetch('/api/v1/tests/listing/', data)
      .then(response => response.json())
      .then(json => dispatch(receiveTests(json)));
    };
  }

Answer 8

If it still doesn't work for you after fixing the credentials.

I also was using the :

  credentials: "same-origin"

and it used to work, then it didn't anymore suddenly, after digging much I realized that I had change my website url to http://192.168.1.100 to test it in LAN, and that was the url which was being used to send the request, even though I was on http://localhost:3000.

So in conclusion, be sure that the domain of the page matches the domain of the fetch url.

Answer 9

My issue was my cookie was set on a specific URL path (e.g., /auth), but I was fetching to a different path. I needed to set my cookie's path to /.

Answer 10

If the fetch is not sending credentials even though the request is not intended to be a cross-origin call, it could be because the request is being processed as cross-origin due to differences in protocols between the origin of the request and location of the response.

I observed that my server was returning Location header with an http URL, while the connection was established over https. As a result, the browser treated the request as cross-origin and applied cross-origin rules. It's worth noting that Firefox (version 114.0.2) and Safari (version 16.1) didn't display any warnings in this scenario, but Chrome (version 114.0.5735.198) showed a (blocked:mixed-content) error, which helped in identifying the issue.

If anyone is interested, in this particular case, SSL termination was being performed in the reverse-proxy, but the gunicorn server was not correctly handling it due to misconfiguration, specifically related to the secure-scheme-headers and forwarded_allow_ips settings. After resolving these settings on the server side, fetch started working fine in all browsers.