C# QR Code Integration

using System.Net.Http;
using System.Text;
using System.Text.Json;

public class QRCodeService
{
    private readonly HttpClient _httpClient;
    private readonly string _apiKey;

    public QRCodeService(string apiKey)
    {
        _httpClient = new HttpClient();
        _apiKey = apiKey;
    }

    public async Task<byte[]> GenerateAsync(string data, int size = 300)
    {
        var request = new
        {
            data = data,
            size = size,
            format = "png"
        };

        var json = JsonSerializer.Serialize(request);
        var content = new StringContent(json, Encoding.UTF8, "application/json");

        _httpClient.DefaultRequestHeaders.Clear();
        _httpClient.DefaultRequestHeaders.Add("Authorization", $"Bearer {_apiKey}");

        var response = await _httpClient.PostAsync(
            "https://www.qrcodeapi.io/api/generate", content);

        response.EnsureSuccessStatusCode();
        return await response.Content.ReadAsByteArrayAsync();
    }
}

[ApiController]
[Route("api/[controller]")]
public class QRController : ControllerBase
{
    private readonly QRCodeService _qrService;

    public QRController(IConfiguration config)
    {
        _qrService = new QRCodeService(config["QRApi:Key"]);
    }

    [HttpGet]
    public async Task<IActionResult> Get([FromQuery] string url)
    {
        var qrCode = await _qrService.GenerateAsync(url);
        return File(qrCode, "image/png");
    }
}

// Add to your services
builder.Services.AddHttpClient<QRCodeService>();
builder.Services.AddScoped<QRCodeService>(sp =>
{
    var config = sp.GetRequiredService<IConfiguration>();
    return new QRCodeService(config["QRApi:Key"]);
});