Web Api convert byte array to base64 for every query

Question

I have multiple methods where I return a query and the problem is that FileContent returns a byte array. I don't want to convert the byte array to base64 in every request I make. Is there a way to apply converting in every web api method so that I don't need to worry about that?

Before this, I saved every file as a base64 string in my db, but I read that it will consume more space than normaly. So I decided to change it to byte array but I dont know how to solve this problem.

public class File
{
    public int FileId { get; set; }

    public string FileName { get; set; }

    public byte[] FileContent { get; set; }

    public Advertentie Advertentie { get; set; }

    public int AdvertentieId { get; set; }

}

public IActionResult Row([FromRoute] int id)
{
    var advertentie = db.Advertenties.Include(x => x.Files).Where(a => a.Id == id).FirstOrDefault();
    // So here each advertentie can contain multiple files, how to convert FileContent to base64 so that every file becomes base64 and return advertentie.
    if(advertentie == null)
    {
        return NotFound();
    }
    return Ok(advertentie);
}

Answer 1

You have several options:

1. Extend your existing FileModel with a get-only property. You can also do this in a lazy-loaded fashion.

public byte[] FileContent { get; set; }
public string FileContentString { get { return Convert.ToBase64String(FileContent); } }

2. Depending on the serializer you're using (eg Newtonsoft.Json), you can override the way properties are serialized. You can eg ignore or convert certain properties.

3. Implement a custom ActionResult

public class Base64Result : ActionResult
{
        private File _file;
        public Base64Result(File file)
        {
           _file = file;
        }

        public override async Task ExecuteResultAsync(ActionContext context)
        {            
            // Do the bas64 magic here (use _file to build a response)
        }
}

and then

public Base64Result Row([FromRoute] int id)
{
   // ...
   return new Base64Result(file);
}

4. You can create a "view-model" with properties of the desired type, fill them, and use an automapper to take care of the rest of the properties.

There are plenty of options.