Top "Preflight" questions

A preflight is an HTTP OPTIONS request that browsers (automatically on their own) send to servers before trying certain kinds of cross-origin requests — in order to determine if a server has opted-in to receiving those kinds of requests.

HAProxy CORS OPTIONS header intercept setup

With my NGinx setup I was able to intercept OPTIONS requests from ajax preflight and respond with the correct CORS …

ajax cors haproxy preflight
Fetch API, custom request headers, CORS, and cross-origin redirects

I need to make an HTTP GET request with custom request headers in-browser and process the result as it streams …

http cors fetch fetch-api preflight
AngularJS $http POST withCredentials fails with data in request body

AngularJS authenticates against server side using REST, and gets the JSESSIONID cookie. In the next step I am trying to …

rest session-cookies cors preflight angularjs-http
Azure Functions: CORS: How to support "Access-Control-Allow-Credentials" header AND OPTIONS pre-flight?

EDITED Since StackOverflow doesn't like you to delete things. This was my own sillyness. What I've learned: The OPTIONS method …

cors azure-functions preflight
nginx config to enable CORS with origin matching

I've tried to use a very popular config for nginx, which enables CORS and supports origin matching using regular expressions. …

nginx cors cross-domain preflight
How to Enable CORS from Nodejs server

I am using react to send data to my API. Every POST request I make gives me an OPTIONS request, …

node.js reactjs preflight
How do I configure embedded Jetty to handle OPTIONS preflight requests?

I am working on a project which is using embedded Jetty (unfortunately I just "inherited" the server side of the …

jetty cors embedded-jetty http-options-method preflight
Disable preflight OPTION request when sending a cross domain request with custom HTTP header

I've just found out that my browser was sending an extra "OPTION" request when trying to make a cross domain …

ajax http-headers cross-domain option preflight
fetch API: Can't add Authorization on Request Header with Chrome

Chrome version: 57.0.2987 Actually, in older Chrome version I also have this problem. I added Authorization on Request Header with my …

http cors fetch fetch-api preflight
What are proper status codes for CORS preflight requests?

What status code should a well-written HTTP server return when it gets a CORS preflight (OPTIONS) request? 200, 204 or something else? …

http cors http-status-codes preflight