DocSpace-client/web/ASC.Web.Core/Utility/UrlShortener.cs

namespace ASC.Web.Core.Utility;

public interface IUrlShortener
{
    Task<string> GetShortenLinkAsync(string shareLink);
}

[Scope]
public class UrlShortener
{
    public bool Enabled { get { return !(Instance is NullShortener); } }

    private IUrlShortener _instance;
    public IUrlShortener Instance
    {
        get
        {
            if (_instance == null)
            {
                if (ConsumerFactory.Get<BitlyLoginProvider>().Enabled)
                {
                    _instance = new BitLyShortener(ConsumerFactory);
                }
                else if (!string.IsNullOrEmpty(Configuration["web:url-shortener:value"]))
                {
                    _instance = new OnlyoShortener(Configuration, CommonLinkUtility, MachinePseudoKeys, ClientFactory);
                }
                else
                {
                    _instance = new NullShortener();
                }
            }

            return _instance;
        }
        set
        {
            _instance = value;
        }
    }

    private IConfiguration Configuration { get; }
    private ConsumerFactory ConsumerFactory { get; }
    private CommonLinkUtility CommonLinkUtility { get; }
    private MachinePseudoKeys MachinePseudoKeys { get; }
    private IHttpClientFactory ClientFactory { get; }

    public UrlShortener(
        IConfiguration configuration,
        ConsumerFactory consumerFactory,
        CommonLinkUtility commonLinkUtility,
        MachinePseudoKeys machinePseudoKeys,
        IHttpClientFactory clientFactory)
    {
        Configuration = configuration;
        ConsumerFactory = consumerFactory;
        CommonLinkUtility = commonLinkUtility;
        MachinePseudoKeys = machinePseudoKeys;
        ClientFactory = clientFactory;
    }
}

public class BitLyShortener : IUrlShortener
{
    public BitLyShortener(ConsumerFactory consumerFactory)
    {
        ConsumerFactory = consumerFactory;
    }

    private ConsumerFactory ConsumerFactory { get; }

    public Task<string> GetShortenLinkAsync(string shareLink)
    {
        return Task.FromResult(ConsumerFactory.Get<BitlyLoginProvider>().GetShortenLink(shareLink));
    }
}

public class OnlyoShortener : IUrlShortener
{
    private readonly string _url;
    private readonly string _internalUrl;
    private readonly byte[] _sKey;

    private CommonLinkUtility CommonLinkUtility { get; }
    private IHttpClientFactory ClientFactory { get; }

    public OnlyoShortener(
        IConfiguration configuration,
        CommonLinkUtility commonLinkUtility,
        MachinePseudoKeys machinePseudoKeys,
        IHttpClientFactory clientFactory)
    {
        _url = configuration["web:url-shortener:value"];
        _internalUrl = configuration["web:url-shortener:internal"];
        _sKey = machinePseudoKeys.GetMachineConstant();

        if (!_url.EndsWith('/'))
        {
            _url += '/';
        }

        CommonLinkUtility = commonLinkUtility;
        ClientFactory = clientFactory;
    }

    public async Task<string> GetShortenLinkAsync(string shareLink)
    {
        var request = new HttpRequestMessage();
        request.RequestUri = new Uri(_internalUrl + "?url=" + HttpUtility.UrlEncode(shareLink));
        request.Headers.Add("Authorization", CreateAuthToken());
        request.Headers.Add("Encoding", Encoding.UTF8.ToString());//todo check 

        var httpClient = ClientFactory.CreateClient();
        using var response = await httpClient.SendAsync(request);
        using var stream = await response.Content.ReadAsStreamAsync();
        using var rs = new StreamReader(stream);
        return CommonLinkUtility.GetFullAbsolutePath(_url + await rs.ReadToEndAsync());
    }

    private string CreateAuthToken(string pkey = "urlShortener")
    {
        using var hasher = new HMACSHA1(_sKey);
        var now = DateTime.UtcNow.ToString("yyyyMMddHHmmss");
        var hash = Convert.ToBase64String(hasher.ComputeHash(Encoding.UTF8.GetBytes(string.Join("\n", now, pkey))));
        return $"ASC {pkey}:{now}:{hash}";
    }
}

public class NullShortener : IUrlShortener
{
    public Task<string> GetShortenLinkAsync(string shareLink)
    {
        return null;
    }
}