Returning binary file from controller in ASP.NET Web API

📝 Blog Post: Returning binary file from controller in ASP.NET Web API

Are you struggling with serving up binary files, like .cab and .exe files, from your ASP.NET Web API? 🤔

Don't worry! We've got you covered with simple solutions that will have your API returning the correct content type and engaging your users. 🚀

The Problem: Incorrect Content Type

Let's take a look at the code snippet provided:

public HttpResponseMessage<Stream> Post(string version, string environment, string filetype)
{
    var path = @"C:\Temp\test.exe";
    var stream = new FileStream(path, FileMode.Open);
    return new HttpResponseMessage<Stream>(stream, new MediaTypeHeaderValue("application/octet-stream"));
}

While this code successfully returns a file, notice that it sets the content type to application/json. 😱 This is not what we want when serving binary files.

The Solution: HttpResponseMessage with ByteArrayContent

To return binary files correctly, we should use the HttpResponseMessage with ByteArrayContent. Here's how you can modify the controller method:

public HttpResponseMessage Post(string version, string environment, string filetype)
{
    var path = @"C:\Temp\test.exe";
    var bytes = File.ReadAllBytes(path);
    var content = new ByteArrayContent(bytes);
    var response = new HttpResponseMessage(HttpStatusCode.OK)
    {
        Content = content,
        Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream")
    };
    
    return response;
}

In this solution, we read the file content as bytes using File.ReadAllBytes. Then, we create a ByteArrayContent object and set it as the content of our HttpResponseMessage. Finally, we set the desired content type, application/octet-stream, in the response headers.

Conclusion and Call-to-Action

And just like that, you're all set to serve up those binary files correctly! 🙌

Remember, it's essential to ensure the correct content type when returning binary files from your ASP.NET Web API. Using the HttpResponseMessage with ByteArrayContent is the way to go.

Now, go ahead and implement this solution in your project. Let us know if you encounter any issues or have any other questions! We're here to help. 😊

Drop a comment below and let us know how this solution worked for you. Feel free to share this blog post with your fellow developers who might be facing the same problem. Sharing is caring! 🌟🤝