Cross origin blocked between Ajax and Spring Controller - ajax

Question

I want a Javascript function to send data to a Spring controller and get a response. However, due to the strict-origin-when-cross-origin Referrer policy, the request does not go through.
Spring Controller :
#Controller
public class EventController {
#ResponseBody
#RequestMapping(value = "/event", method = RequestMethod.POST)
public String handleAjax(#RequestParam Integer id, HttpServletRequest request, HttpServletResponse response) {
response.setHeader("Access-Control-Allow-Origin", "*");
return "OK";
}
}
Javascript functions :
function getContextPath() {
return window.location.pathname.substring(0, window.location.pathname.indexOf("/",2));
}
function move(moveDir,velocity){
$.ajax({
type : "POST",
url : getContextPath() + "/event",
success: function(data){
console.log(data)
}
});
}
I know that I have to allow cross-origin for these files. So far, the things I tried didn't work.
List of what I tried :
-> Adding #CrossOrigin(origins = "http://localhost:8081", maxAge = 3600) to the controller
-> Adding response.setHeader("Access-Control-Allow-Origin", "*"); to the controller
-> Adding crossorigin="anonymous" to the Javascript <script> tag

Answer 1

Your code won't work because you specify to support POST method only
#RequestMapping(value = "/event", method = RequestMethod.POST)
OPTIONS method is required as Preflighted requests in CORS.
So you must support POST and OPTIONS also to make it work.
#RequestMapping(value = "/event")
#RequestMapping(value = "/event", method = { RequestMethod.POST, RequestMethod.OPTIONS })
https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/OPTIONS

Answer 2

I finally got it. There were two problems.
The first was that I had to add that header to the ajax request, to allow the request to be handled by the server: headers: { 'Access-Control-Allow-Origin': '/path_to_request_target' },. Putting '*' instead of '/path_to_request_target' would also work.
The second was with my dispatcher servlet. I had to put .html at the end of the URL : url : getContextPath() + "/event.html",. This is due of the mapping of my dispatcher servlet :
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/index.jsp</url-pattern>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
Adding .html to the URL worked because of <url-pattern>*.html</url-pattern>. Adding a <url-pattern> that satisfied the format of the inital URL would also work.