#PREFLIGHT HTTP SERIAL#

#PREFLIGHT HTTP SERIAL#

This is known as a serial / pipelined network call pattern. The OPTIONS request, and one for the actual HTTP method (GET, POST, etc.). (unless the requests are simple requests, discussed shortly).įrom a performance standpoint, this means that each HTTP communication with a backend of a different origin may require two roundtrips: one for As a result, they will utilize CORS Preflight Requests to communicate securely Two endpoints are hosted on two separate origins. Wanted to communicate with the target backend for.įor example, if your web application hosted on requests data from, these

Web application can proceed with dispatching the actual HTTP request, whether it's a GET, POST, or whatever it originally If the target server accepts the OPTIONS request and notifies the web application that it's allowed to securely call it, the This Preflight request is dispatched transparently by the browser - JavaScript code does not explicitly enact the Preflight Server replies with information telling the requestor whether or not their origin is allowed to call the service for the actual resource. It typically functions by having the browser initiate a Preflight request (with the OPTIONS HTTP method) to the target origin. CORS (Cross Origin Resource Sharing) enables web apps to communicate

Preflight http