piwigodotnet/PiwigoDotnet/Piwigo.Client/PiwigoContext.cs

using System.Net;
using Flurl.Http;
using Flurl.Http.Content;
using Microsoft.Extensions.Logging;
using Piwigo.Client.Contract;

namespace Piwigo.Client;

public class PiwigoContext : IPiwigoContext
{
    private readonly IPiwigoConfiguration _config;
    private readonly CookieJar _cookies = new();
    private readonly ILogger<PiwigoContext> _logger;

    public PiwigoContext(IPiwigoConfiguration configuration, ILogger<PiwigoContext> logger)
    {
        _config = configuration ?? throw new ArgumentNullException(nameof(configuration));
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    public bool IsLoggedIn { get; private set; }

    public async Task LoginAsync(CancellationToken cancellationToken = default)
    {
        if (IsLoggedIn)
        {
            _logger.LogWarning("The client is already logged in!");
            return;
        }

        var userName = _config.UserName;
        if (string.IsNullOrWhiteSpace(userName))
        {
            throw new PiwigoException("username cannot be null or whitespace.");
        }

        var password = _config.Password;
        if (string.IsNullOrWhiteSpace(password))
        {
            throw new PiwigoException("password cannot be null or whitespace.");
        }

        _logger.LogInformation("Logging into {PiwigoBaseUri} using username {Username}", _config.BaseUri, userName);

        var response = await ConfigureRequest(_logger)
            .PostMultipartAsync(c => c.AddMethod("pwg.session.login").AddString("username", userName).AddString("password", password), cancellationToken);

        if (response.StatusCode != (int)HttpStatusCode.OK)
        {
            throw new PiwigoException($"Could not log in to {_config.BaseUri} using username {userName}");
        }

        _logger.LogInformation("Logging in succeeded");
        IsLoggedIn = true;
    }

    public async Task LogoutAsync(CancellationToken cancellationToken = default)
    {
        if (!IsLoggedIn)
        {
            _logger.LogWarning("Tried to log out from {Uri} but was not logged in!", _config.BaseUri);
            return;
        }

        _logger.LogInformation("Logging out from {Uri}", _config.BaseUri);
        await PostAsync<PiwigoResponse>(_logger, "pwg.session.logout", cancellationToken);
        IsLoggedIn = false;
        _cookies.Clear();
    }

    public Task<T> PostAsync<T>(ILogger logger, string method, CancellationToken cancellationToken = default) where T : PiwigoResponse
    {
        return PostInternalAsync<T>(logger, method, null, cancellationToken);
    }

    public Task<T> PostAsync<T>(ILogger logger, string method, IDictionary<string, string> formParams, CancellationToken cancellationToken = default) where T : PiwigoResponse
    {
        return PostInternalAsync<T>(logger, method, formParams, cancellationToken);
    }

    private static void AddFormParams(CapturedMultipartContent c, IDictionary<string, string> formParams)
    {
        foreach (var formParam in formParams)
        {
            c.AddString(formParam.Key, formParam.Value);
        }
    }

    private async Task<T> PostInternalAsync<T>(ILogger logger, string method, IDictionary<string, string>? formParams, CancellationToken cancellationToken) where T : PiwigoResponse
    {
        await EnsureLoggedInAsync(cancellationToken);

        logger.LogInformation("executing {Method} using post", method);

        var response = await ConfigureRequest(logger).PostMultipartAsync(c =>
        {
            c.AddMethod(method);
            if (formParams != null)
            {
                AddFormParams(c, formParams);
            }
        }, cancellationToken);

        if (response.StatusCode != (int)HttpStatusCode.OK)
        {
            throw new PiwigoException($"failed to call {method} on {_config.BaseUri}: {response.StatusCode}");
        }

        var typedResponse = await response.GetJsonAsync<T>();

        if (!typedResponse.IsOk)
        {
            throw new PiwigoException($"failed to call {method} on {_config.BaseUri}: {typedResponse.Status} - Error: {typedResponse.Error} - Message:{typedResponse.Message}");
        }

        return typedResponse;
    }

    private async ValueTask EnsureLoggedInAsync(CancellationToken cancellationToken)
    {
        if (IsLoggedIn)
        {
            return;
        }

        await LoginAsync(cancellationToken);
    }

    private IFlurlRequest ConfigureRequest(ILogger logger)
    {
        if (logger == null)
        {
            throw new ArgumentNullException(nameof(logger));
        }

        return _config.BaseUri.WithCookies(_cookies).ConfigureRequest(r => r.AfterCallAsync = call => LogResponse(call, logger));
    }

    private static async Task LogResponse(FlurlCall call, ILogger logger)
    {
        var responseString = await call.Response.GetStringAsync();
        logger.LogDebug("Response: {Response}", responseString);
    }
}