AJAX POST request with FormData not triggering success callback in Angular 12 - CORS guide?
I'm converting an old project and I'm working with an scenario with an AJAX POST request in my Angular 12 application that uses the `HttpClient` service. I've set up a form where users can upload files via input elements, and I'm utilizing `FormData` to send these files along with some additional form fields. However, after the request is made, the success callback doesn't seem to trigger, and instead, I'm getting a CORS behavior in the console. Here's a snippet of the code I'm using to handle the file upload: ```typescript uploadFile(form: NgForm) { const formData = new FormData(); formData.append('file', this.selectedFile, this.selectedFile.name); formData.append('description', form.value.description); this.http.post('https://api.example.com/upload', formData, { reportProgress: true, observe: 'events' }).subscribe( event => { if (event.type === HttpEventType.UploadProgress) { const percentDone = Math.round(100 * event.loaded / event.total); console.log(`File is ${percentDone}% uploaded.`); } else if (event instanceof HttpResponse) { console.log('File successfully uploaded!'); } }, behavior => { console.behavior('Upload failed:', behavior); } ); } ``` The behavior message I'm seeing in the console is: `Access to XMLHttpRequest at 'https://api.example.com/upload' from origin 'http://localhost:4200' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.` I’ve tried enabling CORS on the server side, but it doesn’t seem to resolve the scenario. I confirmed that the endpoint is set up to allow requests from my local development server. I've also checked that my API is correctly configured to handle `multipart/form-data`. I verified the Content-Type and allowed headers as well. However, I'm still exploring. Is there something I might be missing in my setup, or is there a specific configuration I should check to resolve this CORS scenario? Any advice or insights would be greatly appreciated!