Cross-Origin Resource Sharing Example with ASP.NET

Table of Contents

1. Introduction
2. Server-Side Configuration
3. Client-Side Ajax Call
4. Further Reading
5. Conclusion

Introduction

This is a simple example of how to achieve cross-domain access in ASP.NET. The following example is the simplest approach, which just makes it work by modifying web.config.

Let's assume you have the following two sites. client-site.com is trying to access server-site.com's Ajax API, /api/getMyData.

• client-site.com

• server-site.com

  • contains /api/getMyData

Server-Side Configuration

What you have to do at server-site.com is the following — you let your server return the Access-Control-Allow-Origin header in the HTTP response.

Client-Side Ajax Call

On client-site.com you can just call as follows, assuming your API is at server-site.com/api/getMyData:

$.ajax({ url: "http://server-site.com/api/getMyData" }).then(function () {
            console.info("done with call server-site.com's api");
        });

Further Reading

For more detailed information about how to enable CORS for a specific HTTP method, a specific site, or other useful libraries, see:

Enabling Cross-Origin Requests in ASP.NET Web API 2

Conclusion

By adding the Access-Control-Allow-Origin header in your web.config, you can quickly enable cross-domain access in ASP.NET. For more fine-grained control, consider using the ASP.NET Web API 2 CORS library.