In your controller, you can generate a unique, encrypted identifier for the file:
using System;
using System.IO;
using System.Security.Cryptography;
using Microsoft.AspNetCore.Mvc;
namespace DownloadFileExample.Controllers
{
public class DownloadController : Controller
{
[HttpGet]
public IActionResult Download(string id)
{
// Decrypt the identifier to get the file path
string filePath = DecryptFileIdentifier(id);
// Check if the file exists
if (!System.IO.File.Exists(filePath))
{
return NotFound();
}
// Return the file as a FileResult
return File(System.IO.File.OpenRead(filePath), “application/pdf”, Path.GetFileName(filePath));
}
private string DecryptFileIdentifier(string encryptedIdentifier)
{
// Your implementation for decrypting the encrypted identifier goes here
// For this example, let’s assume the encrypted identifier is just a base64-encoded string of the file path
return System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(encryptedIdentifier));
}
}
}
To create an encrypted download link, you could generate an encrypted identifier for the file and include it in the link:
@functions {
private string EncryptFileIdentifier(string filePath)
{
// Your implementation for encrypting the file path goes here
// For this example, let’s assume the encrypted identifier is just a base64-encoded string of the file path
return Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(filePath));
}
}
This is just one way to create an encrypted download link for a file in ASP.NET Core. You can use other encryption techniques to encrypt the identifier, such as AES encryption, if needed. The specific encryption technique you choose will depend on the level of security you require for your application.
The client/user will not know the actual web path or file name as the information is encrypted and can only be decrypted by the server. By encoding the file path in the download link, you are effectively obscuring the actual file location from the client/user. This can help to prevent unauthorized access to the file and protect sensitive information.
In the example I provided earlier, the file path is encrypted using a base64 encoding and included in the download link. When the user clicks the link, the encrypted identifier is passed to the Download action in the controller. The controller then uses the DecryptFileIdentifier method to decrypt the identifier and retrieve the actual file path. Finally, the file is returned to the client/user as a FileResult.