Develop Reference

Fetching from CORS-API not allowed for localhost

I'm working on a React App which needs to fetch data from an Api.
I made it work with fake data.
fetch('https://jsonplaceholder.typicode.com/posts')
.then((response) => {
console.log(response);
return response.json();
})
.then((json) => {
return json;
})
Now i wanted to get data from our local Api with Apigility.
fetch('http://localserver:8081/news')
.then((response) => {
console.log(response);
return response.json();
})
.then((json) => {
return json;
})
But i get net::ERR_ABORTED 403 (The origin "http://localho.st:5000" is not authorized). The app was created with create-react-app and gets served by its run script.
Now the thing is it works, when i enter http://localserver:8081/news in Firefox and Edge. I receive the json data. The same when trying it with my phone, curl or an api tester.
This is the answer when trying to fetch from the app:
HTTP/1.1 403 The origin "http://localhost:3000" is not authorized
Content-Type: text/html; charset=UTF-8
Server: Microsoft-IIS/10.0
X-Powered-By: PHP/7.0.30
Access-Control-Allow-Origin: *
Date: Thu, 07 Oct 2021 12:59:08 GMT
Content-Length: 0
And when calling from browser:
HTTP/1.1 200 OK
Content-Type: application/hal+json
Vary: Origin
Server: Microsoft-IIS/10.0
X-Powered-By: PHP/7.0.30
WWW-Authenticate: Bearer realm="Service"
Access-Control-Allow-Origin: *
Date: Thu, 07 Oct 2021 13:03:08 GMT
Content-Length: 133933
I've read about setting up a proxy to get CORS calls, but i wondered if there are other solutions to this problem.
EDIT:
localserver:
GET /news HTTP/1.1
Host: 10.254.2.10:8081
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0
Accept: */*
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Origin: http://localhost:3000
Referer: http://localhost:3000/
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
HTTP/1.1 403 The origin "http://localhost:3000" is not authorized
Content-Type: text/html; charset=UTF-8
Server: Microsoft-IIS/10.0
X-Powered-By: PHP/7.0.30
Access-Control-Allow-Origin: *
Date: Thu, 07 Oct 2021 14:15:22 GMT
Content-Length: 0
https://jsonplaceholder.typicode.com/posts
Host: jsonplaceholder.typicode.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0
Accept: */*
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Origin: http://localhost:3000
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: cross-site
Referer: http://localhost:3000/
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
HTTP/3 200 OK
date: Thu, 07 Oct 2021 14:17:37 GMT
content-type: application/json; charset=utf-8
x-powered-by: Express
x-ratelimit-limit: 1000
x-ratelimit-remaining: 999
x-ratelimit-reset: 1633547463
access-control-allow-origin: http://localhost:3000
vary: Origin, Accept-Encoding
access-control-allow-credentials: true
cache-control: max-age=43200
pragma: no-cache
expires: -1
x-content-type-options: nosniff
etag: W/"6b80-Ybsq/K6GwwqrYkAsFxqDXGC7DoM"
via: 1.1 vegur
cf-cache-status: HIT
age: 4307
expect-ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
report-to: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v3?s=qYfd07Dc%2BG9NUgzVp1DHMPuBcDx8UOvlbWfDD51OGSN8s74yaJFooN99m7nG4NSHV%2BeqY78Qw%2Bb7ozFdWCmF8ngPRnQPc3tlVdrSwGy8TKWYLwWSEYI4YE88GU5yyErQ8P5jLa5tUkPnB4FA6mg7"}],"group":"cf-nel","max_age":604800}
nel: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
server: cloudflare
cf-ray: 69a7c10bdbf66d8f-MUC
content-encoding: br
alt-svc: h3=":443"; ma=86400, h3-29=":443"; ma=86400, h3-28=":443"; ma=86400, h3-27=":443"; ma=86400

Create-React-App comes with a simple way to handle this: add a proxy field to your package.json file as shown below. In this case, a request is made from server A to server B
"proxy": "http://localserver:8081/",

You can run a local reverse proxy to get the API calls from the same origin (say mapping localhost:3000/api/news to localhost:8081/news) but then it'd probably be easier to set up a CORS proxy.
You could try to make the API JSONP and circumvent the same origin policy that way, but this is likely also more hairy than setting up a CORS proxy.
Long story short: Whenever you make requests across origins, CORS needs to be set up.

Chrome not persisting CORS cookie

The setup uses a Backbone Model, Nginx server. The users enter their username and password which is then passed via a post. The server authenticates and returns a session cookie.
When the backend and front-end are on the same server (e.g. connect via localhost) the cookie is stored. However when the connection is remote, it is not stored in Chrome; however, it is stored in Safari and FireFox.
Ajax is setup via
$.ajaxSetup({
crossDomain: true,
xhrFields: {
withCredentials: true
}
});
The request headers are
POST /login HTTP/1.1
Host: localhost:8102
Connection: keep-alive
Content-Length: 59
Accept: application/json, text/javascript, */*; q=0.01
Origin: http://127.0.0.1:9102
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36
Content-Type: application/json
DNT: 1
Referer: http://127.0.0.1:9102/somefolder
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.8
The response headers are
HTTP/1.1 200 OK
access-control-allow-origin: http://127.0.0.1:9102
access-control-allow-credentials: true
vary: origin,accept-encoding
access-control-expose-headers: WWW-Authenticate,Server-Authorization
content-type: text/html; charset=utf-8
set-cookie: na-auth-token=encrypted-string; Max-Age=86400; Expires=Thu, 27 Apr 2017 13:32:44 GMT; HttpOnly; SameSite=Strict; Path=/
cache-control: no-cache
content-encoding: gzip
Date: Wed, 26 Apr 2017 13:32:44 GMT
Connection: keep-alive
Transfer-Encoding: chunked
In FireFox and Safari the cookie is stored just fine, but in Chrome it gets the response and tosses the cookie without any notification.
Update
The cookie is actually being saved under the localhost domain, however when you navigate back to the page (e.g. via a window.location.reload) the cookie disappears.

So the answer to my question lied in a library we were using
hapi-auth-cookie
The package updated and a flag was introduced isSameSite. Changed this value to false to allow the cors cookie to persist between pages loads.

Browser refresh corrupts bundled javascript

I added ASP.NET javascript bundling and minfication to our website, and have discovered that now if I refresh the website, the bundled javascript file is downloaded as gzip but never uncompressed by the browser, so the site of course doesn't work since the javascript is still compressed. If I refresh again, the site is fine. Refresh again, corrupt. Back and forth. This is ONLY happening in Chrome and Safari, but not in IE.
Watching in Fiddler, IE gets the javascript the first time, and subsequent refreshes return 304 not modified which is correct. Chrome / Safari refreshes continually return 200 for each refresh.
If I run my website locally hosting it in IIS Express, this problem does NOT occur. It's only in our other QA, Staging and Production environments where the website is hosted by IIS 7.5.
I did a Fiddler compare of the good Chrome request and the bad Chrome request to see what's different. They are identical except the bad request has the "If-Modified-Since" header.
The response from the server when the "If-Modified-Since" header is there has a Content-Type of "application/javascript", and this is what I think is causing the problem, the browser doesn't know it should uncompress the response body.
Here is the GOOD request and response (body omitted for brevity):
GET https://wwwq.website.com/Scripts/main.js?v=z3QOtK2bjf3mvSQyLf2KY82lAidw4JR0ePo01WHF93U1 HTTP/1.1
Host: www.website.com
Connection: keep-alive
Accept: */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.97 Safari/537.36
DNT: 1
Referer: https://www.website.com/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: < cookies omitted >
HTTP/1.1 200 OK
Date: Fri, 05 Feb 2016 13:46:30 GMT
Server: Microsoft-IIS/7.5
Cache-Control: public
Content-Type: text/javascript; charset=utf-8
Expires: Sat, 04 Feb 2017 13:46:31 GMT
Last-Modified: Fri, 05 Feb 2016 13:46:31 GMT
Vary: User-Agent,Accept-Encoding
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Via: 1.1 wwwq.website.com (Access Gateway-ag-2772908347919084-467794)
Keep-Alive: timeout=300, max=99
Connection: Keep-Alive
Content-Length: 62702
Here is the BAD request and response (body omitted for brevity):
GET https://www.website.com/Scripts/main.js?v=z3QOtK2bjf3mvSQyLf2KY82lAidw4JR0ePo01WHF93U1 HTTP/1.1
Host: www.website.com
Connection: keep-alive
Cache-Control: max-age=0
Accept: */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.97 Safari/537.36
DNT: 1
Referer: https://www.website.com/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: < cookies omitted >
If-Modified-Since: Fri, 05 Feb 2016 13:46:31 GMT
HTTP/1.1 200 OK
Date: Fri, 05 Feb 2016 13:46:43 GMT
Server: Microsoft-IIS/7.5
Cache-Control: private
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Vary: Accept-Encoding
Via: 1.1 www.website.com (Access Gateway-ag-2772908347919084-467849)
Content-Length: 16042
Keep-Alive: timeout=300, max=94
Connection: Keep-Alive
Content-Type: application/javascript
If anyone can help me out I would be incredibly grateful I am running out of ideas.

Get HTTP content

This is my Http header trace when i access pwd.html
host:port/pwd.html?type=Msg=8
POST /pwd.html?type=Msg=8 HTTP/1.1
Host: host:port
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: anotherhost:port/referrer
Cookie: SomeCookie=loggedoutcontinue; targetURL=Someurl
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 4936
APP_REQ=324823823
HTTP/1.1 200 OK
Date: Tue, 26 Aug 2014 15:05:29 GMT
Server: Application-Server
Last-Modified: Mon, 25 Aug 2014 18:55:15 GMT
Accept-Ranges: bytes
Content-Length: 1336
Keep-Alive: timeout=5, max=99
Connection: Keep-Alive
Content-Type: text/html
Content-Language: en
How can I read the value of APP_REQ from my pwd.html using Javascript? Its not part of query string or URL but it is part of request.

This isn't possible, unless the server were to include this value in the content of pwd.html itself. This requires something server-side like PHP or Node.js.

FireFox refuses response to OPTIONS

I have a page served by HTTP. Client code sends AJAX-requests for authorization to the same domain, but on HTTPS. (so it is CORS).
FireFox generates this request: // domains and cookies are changed
OPTIONS /auth/registration/json/info/ HTTP/1.1
Host: my-site.dev
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:25.0) Gecko/20100101 Firefox/25.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: ru-ru,pl;q=0.8,ru;q=0.6,en-us;q=0.4,en;q=0.2
Accept-Encoding: gzip, deflate
Origin: http://my-site.dev
Access-Control-Request-Method: GET
Access-Control-Request-Headers: x-requested-with
Connection: keep-alive
And my server responds:
HTTP/1.1 200 OK
Server: nginx/1.4.1
Date: Thu, 07 Nov 2013 09:55:55 GMT
Content-Type: text/html; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Access-Control-Allow-Origin: https://my-site.dev
Vary: Cookie
Access-Control-Allow-Origin: http://my-site.dev
Access-Control-Allow-Methods: OPTIONS, GET
Set-Cookie: csrftoken=foobar; expires=Thu, 06-Nov-2014 09:55:55 GMT; Max-Age=31449600; Path=/
0
FireBug shows that OPTIONS request succeeded, but does not fire GET request after it:
What is wrong in my response?

Qantas 94 Heavy, you're right. There should be only one Access-Control-Allow-Origin header with only one domain: domain, that specified in Origin request header.
This is right answer that firefox accepts:
HTTP/1.1 200 OK
Server: nginx/1.4.1
Date: Thu, 07 Nov 2013 09:55:55 GMT
Content-Type: text/html; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Cookie
Access-Control-Allow-Origin: http://my-site.dev // The same as `Origin`
Access-Control-Allow-Methods: OPTIONS, GET
Set-Cookie: csrftoken=foobar; expires=Thu, 06-Nov-2014 09:55:55 GMT; Max-Age=31449600; Path=/
0