Access to XMLHttpRequest at 'http://localhost:3000/api/ringers' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response. code example
Example 1: Access to XMLHttpRequest at 'http://localhost/MySQL_pracs/InsertUser.php' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.
//Access to XMLHttpRequest at 'http://localhost/[api path].php' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.
//The error is simply saying that "Content-Type" is missing from "Access-Control-Allow-Headers".
//Therefore we need to add "Content-Type" to "Access-Control-Allow-Headers".
<?php
header('Access-Control-Allow-Headers: Content-Type');
-----
?>
Example 2: ccess to XMLHttpRequest at 'http://127.0.0.1:5000/ has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
@app.route('your route', methods=['GET'])
def yourMethod(params):
response = flask.jsonify({'some': 'data'})
response.headers.add('Access-Control-Allow-Origin', '*')
return response