ERROR DE CORS | Angular y .Net | Web Api

When working with Angular and .Net Web Api, you may encounter an error known as CORS (Cross-Origin Resource Sharing). This error occurs when a web application makes a request to a different domain than the one it was served from. This is a security feature implemented by web browsers to prevent unauthorized access to data.

To fix this error, you can make changes to the server-side configuration of the .Net Web Api and the client-side configuration of the Angular application. Here’s how you can do it:

.Net Web Api Configuration

In the .Net Web Api, you can enable CORS by installing the Microsoft.AspNet.WebApi.Cors package from NuGet. Once installed, you can enable CORS in the WebApiConfig.cs file by adding the following code:

“`csharp
config.EnableCors();
“`

You can also specify which origins are allowed to access the Web Api by using the EnableCors attribute on specific controllers or actions:

“`csharp
[EnableCors(origins: “http://example.com”, headers: “*”, methods: “*”)]
“`

Angular Configuration

In the Angular application, you can handle CORS by configuring the HttpClient service to include the necessary headers when making HTTP requests. You can do this by creating a custom HttpInterceptor that adds the required headers to every outgoing request. Here’s an example of how you can achieve this:

“`typescript
@Injectable()
export class CorsInterceptor implements HttpInterceptor {
intercept(req: HttpRequest, next: HttpHandler): Observable<HttpEvent> {
req = req.clone({
setHeaders: {
‘Access-Control-Allow-Origin’: ‘*’,
‘Access-Control-Allow-Methods’: ‘GET, POST, OPTIONS, PUT, PATCH, DELETE’,
‘Access-Control-Allow-Headers’: ‘Origin, X-Requested-With, Content-Type, Accept, Authorization’
}
});
return next.handle(req);
}
}
“`

Once you have created the interceptor, you can add it to the providers array in your AppModule and register it with the HttpClient module by using the HTTP_INTERCEPTORS token.

“`typescript
providers: [
{ provide: HTTP_INTERCEPTORS, useClass: CorsInterceptor, multi: true }
]
“`

By making these changes to the server-side and client-side configurations, you can effectively handle the CORS error and ensure that your Angular application can communicate with the .Net Web Api without any issues. This will allow you to make cross-origin requests and access the necessary data from the Web Api.

Hopefully, this article has helped you understand how to handle the CORS error when working with Angular and .Net Web Api. With the right configurations in place, you can seamlessly integrate these technologies and build powerful web applications.