preflight

问题 I have followed this step to setup my server to enable CORS. https://docs.microsoft.com/en-us/aspnet/web-api/overview/security/enabling-cross-origin-requests-in-web-api But now in my browser dev console, I see this error message: XMLHttpRequest cannot load https://serveraddress/abc. Response for preflight is invalid (redirect) Do you know what can I do to fix it? I am making a CORS request in HTTPS. I think that is causing the \'preflight is invalid (redirect)\' failure. But I don\'t know why

问题 Cross-origin resource sharing is a mechanism that allows a web page to make XMLHttpRequests to another domain (from wikipedia). I\'ve been fiddling with CORS for the last couple of days and I think I have a pretty good understanding of how everything works. So my question is not about how CORS / preflight work, it\'s about the reason behind coming up with preflights as a new request type . I fail to see any reason why server A needs to send a preflight (PR) to server B just to find out if the

问题 I\'m designing an API that allows the user to authenticate (using tokens) and that contains redirects within the same domain. Now, for an unauthenticated request to an endpoint that returns 303, GET /documents/123 --> 303 redirect to `/documents/abc` GET /documents/abc --> 200 everything works out nicely. Let\'s do an authenticated request to the same endpoint where the Authorization header is sent. This makes the request a preflighted request and the browser does a preflight OPTIONS request,

问题 I\'m trying to setup AngularJS to communicate with a cross-origin resource where the asset host which delivers my template files is on a different domain and therefore the XHR request that angular performs must be cross-domain. I\'ve added the appropriate CORS header to my server for the HTTP request to make this work, but it doesn\'t seem to work. The problem is that when I inspect the HTTP requests in my browser (chrome) the request sent to the asset file is an OPTIONS request (it should be

问题 I\'m trying to fetch some data from the REST API of HP Alm. It works pretty well with a small curl script - I get my data. Now doing that with JavaScript, fetch and ES6 (more or less) seems to be a bigger issue. I keep getting this error message: Fetch API cannot load . Response to preflight request doesn\'t pass access control check: No \'Access-Control-Allow-Origin\' header is present on the requested resource. Origin \'http://127.0.0.1:3000\' is therefore not allowed access. The response