redirect after a fetch post call

I am creating an social login page with an Access Management (AM) server. When user click on the login button then I make a fetch http post call to AM server. AM server generates a HTTP 301 redirect response with auth cookies to the social login page. I need to follow somehow this redirect response and show the new content in the web browser.

UI: ReactJS

Request:

POST /api/auth/socialauth/initiate HTTP/1.1
Host	example.com
User-Agent	Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:49.0)
Accept	*/*
Accept-Language	en-US,en;q=0.5
Accept-Encoding	gzip, deflate
origin	http://web.example.com:8080
Referer	http://web.example.com:8080/myapp/login
Cookie	authId=...; NTID=...

Response

HTTP/1.1 307 Temporary Redirect
https://www.facebook.com/dialog/oauth?client_id=...&scope=public_profile%2Cemail&redirect_uri=http%3A%2F%2Fam.example.com%3A8083%2Fopenam%2Foauth2c%2FOAuthProxy.jsp&response_type=code&state=qtrwtidnwdpbft4ctj2e9mv3mjkifqo

React code:

initiateSocialLogin() {
    var url = "/api/auth/socialauth/initiate";

    fetch(url, { method: 'POST' })
        .then(response => {
            // HTTP 301 response
            // HOW CAN I FOLLOW THE HTTP REDIRECT RESPONSE?
        })
        .catch(function(err) {
            console.info(err + " url: " + url);
        });
}

How I can follow the redirect response and show the new content in the web browser?

Request.redirect could be "follow", "error" or "manual".

> If it is "follow", fetch() API follows the redirect response (HTTP > status code = 301,302,303,307,308). > > If it is "error", fetch() API treats the redirect response as an > error. > > > If it is "manual", fetch() API doesn't follow the redirect and returns > an opaque-redirect filtered response which wraps the redirect > response.

Since you want to redirect after a fetch just use it as

fetch(url, { method: 'POST', redirect: 'follow'})
    .then(response => {
        // HTTP 301 response
    })
    .catch(function(err) {
        console.info(err + " url: " + url);
    });

Have a look at properties url redirected of Response object: Doc says that this is

> "Experimental. Expect behavior to change in the future" > > The url read-only property of the Response interface contains the URL > of the response. The value of the url property will be the final URL > obtained after any redirects.

In my experiments, this 'url' property was exactly the same as the value of Location header in Chrome (Version 75.0.3770.100 (Official Build) (64-bit)) Network console.

The code to deal with redirecting link my look like this:

   fetch(url, { method: 'POST' })
    .then(response => {
        // HTTP 301 response
        // HOW CAN I FOLLOW THE HTTP REDIRECT RESPONSE?
        if (response.redirected) {
            window.location.href = response.url;
        }
    })
    .catch(function(err) {
        console.info(err + " url: " + url);
    });

I tested it working with react.js same-origin script with fetch AJAX call facing redirects 302 from server.

P.S. In SPA apps, redirect responses are unlikely, maybe this is the reason why ajax vendors apply little attention to this functionality. See also these discussions: here here

It is not possible to follow a redirect to a new HTML page with javascript.

fetch(url, { method: 'POST', redirect: "follow" });

will simply perform another request to the redirected location which will be returned as data and not rendered by the browser. You might expect to be able to use { redirect : "manual" }, get the redirected location from the response and navigate to the page with Javascript, but unfortunately the redirected location is not returned, see https://github.com/whatwg/fetch/issues/763.

I have a similar issue and I believe that the answer for fetch inside React is the same as it is for ajax inside JQuery - if you are able to detect that the response is a redirect, then update the window.location.href with the response.url

See for example: https://stackoverflow.com/questions/199099/how-to-manage-a-redirect-request-after-a-jquery-ajax-call

Note that 'if you are able to detect that the response is a redirect' might be the tricky part. Fetch responses may contain a 'redirected' flag (see https://developer.mozilla.org/en-US/docs/Web/API/Response) but I've found that is not the case in Chrome. I also find in Chrome I get a 200 status response rather than a redirect status - but that could be something with our SSO implementation. If you are using a fetch polyfill with IE then you'll need to check whether response.url is included or not.