CORS

Question 1

What does CORS stand for?

Answer 1

Cross-Origin Resource Sharing

Question 2

What is CORS?

Answer 2

CORS is an HTTP-header based mechanism that allows a server to indicate any origins (domain, scheme, or port) other than its own from which a browser should permit loading resources.

Question 3

You load a React app from www.domain1.com.
Then you make requests using JS and fetch to the same domain.
Do you need to consider CORS?

Answer 3

No as you are sending requests to the original domain you don’t need to worry about CORS.

Question 4

You load a React app from www.domain1.com.
Then you make requests using JS and fetch to www.domain2.com
Do you need to consider CORS?

Answer 4

Yes, as you are sending requests to a different domain than where you retrieved the React app from www.domain2.com will need to send the correct CORS headers.

Question 5

What defines the origin?

Answer 5

The main request made for a web page. For a React app it would be getting the index.html. (I assume)

Question 6

A request is sent via JS with these headers, where is the request being sent to and from?
Host: oneedfhirtest.azurewebsites.net
Origin: http://localhost:3000

Answer 6

The request is being sent to the server oneedfhirtest.azurewebsites.net
from the application that was loaded from http://localhost:3000.