phronCare/phronCare.UIBlazor/Services/Authorization/CustomAuthorizationProvider.cs

using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.JSInterop;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text.Json;
using phronCare.UIBlazor.Extensions;

namespace phronCare.UIBlazor.Services.Authorization
{
    public class CustomAuthorizationProvider: AuthenticationStateProvider,ILoginService
    {
        private readonly IJSExtensions js;
        private readonly HttpClient httpClient;
        public static readonly string TOKENKEY = "phronCareTokenKey";
        private AuthenticationState Anonimo => new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
        public CustomAuthorizationProvider(IJSRuntime _js, HttpClient httpClient) //Constructor
        {
            this.httpClient = httpClient;
            js = new IJSExtensions(_js);
        }
        public async override Task<AuthenticationState> GetAuthenticationStateAsync()
        {
            var token = await js.GetFromLocalStorage(TOKENKEY);
            if (string.IsNullOrEmpty(token))
            {
                return Anonimo;
            }
            return BuildAuthenticationState(token);
        }
        private AuthenticationState BuildAuthenticationState(string token)
        {
            httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(ParseClaimsFromJwt(token), "jwt")));
        }
        public async Task<TokenData> GetTokenData()
        {
            var token = await js.GetFromLocalStorage(TOKENKEY);
            //TokenData result = JsonSerializer.Deserialize<TokenData>(token);
            //return result;
            TokenData? result = JsonSerializer.Deserialize<TokenData>(token);

            if (result == null)
            {
                // Maneja el caso en el que la deserialización falla y devuelve null
                // Puedes lanzar una excepción, retornar un valor predeterminado, o manejar el error de otra forma
                throw new InvalidOperationException("El token no se pudo deserializar en un objeto TokenData.");
            }

            return result;
        }
        public async Task Login(string token)
        {
            await js.RemoveItem(TOKENKEY);
            await js.SetInLocalStorage(TOKENKEY, token);
            var authState = BuildAuthenticationState(token);
            NotifyAuthenticationStateChanged(Task.FromResult(authState));
        }
        public async Task Logout()
        {
            httpClient.DefaultRequestHeaders.Authorization = null;
            await js.RemoveItem(TOKENKEY);
            NotifyAuthenticationStateChanged(Task.FromResult(Anonimo));
        }
        //private IEnumerable<Claim> ParseClaimsFromJwt(string jwt)
        //{
        //    var claims = new List<Claim>();
        //    var payload = jwt.Split('.')[1];
        //    var jsonBytes = ParseBase64WithoutPadding(payload);
        //    var keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonBytes);
        //    keyValuePairs.TryGetValue(ClaimTypes.Role, out object roles);

        //    if (roles != null)
        //    {
        //        if (roles.ToString().Trim().StartsWith("["))
        //        {
        //            var parsedRoles = JsonSerializer.Deserialize<string[]>(roles.ToString());
        //            foreach (var parsedRole in parsedRoles)
        //            {
        //                claims.Add(new Claim(ClaimTypes.Role, parsedRole));
        //            }
        //        }
        //        else
        //        {
        //            claims.Add(new Claim(ClaimTypes.Role, roles.ToString()));
        //        }
        //        keyValuePairs.Remove(ClaimTypes.Role);
        //    }
        //    claims.AddRange(keyValuePairs.Select(kvp => new Claim(kvp.Key, kvp.Value.ToString())));
        //    return claims;
        //}
        private IEnumerable<Claim> ParseClaimsFromJwt(string jwt)
        {
            var claims = new List<Claim>();
            var payload = jwt.Split('.')[1];
            var jsonBytes = ParseBase64WithoutPadding(payload);
            var keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonBytes);

            if (keyValuePairs != null && keyValuePairs.TryGetValue(ClaimTypes.Role, out object roles))
            {
                // Verificamos si roles no es null y lo convertimos a string de manera segura
                string rolesString = roles?.ToString() ?? string.Empty;  // Aquí usamos un valor por defecto si es null

                if (!string.IsNullOrEmpty(rolesString))
                {
                    if (rolesString.Trim().StartsWith("["))
                    {
                        var parsedRoles = JsonSerializer.Deserialize<string[]>(rolesString) ?? Array.Empty<string>();
                        foreach (var parsedRole in parsedRoles)
                        {
                            claims.Add(new Claim(ClaimTypes.Role, parsedRole));
                        }
                    }
                    else
                    {
                        claims.Add(new Claim(ClaimTypes.Role, rolesString));
                    }
                }

                keyValuePairs.Remove(ClaimTypes.Role);
            }

            if (keyValuePairs != null)
            {
                claims.AddRange(keyValuePairs.Select(kvp => new Claim(kvp.Key, kvp.Value?.ToString() ?? "defaultValue")));
            }

            return claims;
        }
        private byte[] ParseBase64WithoutPadding(string base64)
        {
            switch (base64.Length % 4)
            {
                case 2: base64 += "=="; break;
                case 3: base64 += "="; break;
            }
            return Convert.FromBase64String(base64);
        }
        public class TokenData
        {
            public string userName { get; set; } = string.Empty;
            public string token { get; set; } = string.Empty;
            public string role { get; set; } = string.Empty;
            public DateTime expiryTimeStamp { get; set; }
        }
    }
}