Access Token (ASP.NET Core)

To be able to use Sdir public APIs you need to ble able to authenticate and have the necessary permissions.

Maskinporten integration

In this example you can use the certificate in the .p12-keystore format.

Maskinporten settings:

ASP.NET Core example code:

async Task<AccessTokenModel> CreateMaskinportenToken()
        {
            var jwtAssertion = GetJwtAssertion(_settings);
            var content = GetUrlEncodedContent(jwtAssertion);
            var httpClient = new HttpClient
            {
                BaseAddress = new Uri(_settings.maskinportenBaseAddress)
            };

            var response = await httpClient.PostAsync("token", content);
            if (!response.IsSuccessStatusCode)
            {
                var errorMessage = await response.Content.ReadAsStringAsync();
                throw new HttpRequestException($"Something went wrong. {errorMessage}");
            }
            
            return await System.Text.Json.JsonSerializer.DeserializeAsync<AccessTokenModel>( await response.Content.ReadAsStreamAsync());           
        }

        private static string GetJwtAssertion(MaskinportenSettings _settings)

        {
            var certificate = new X509Certificate2(_settings.certificatePath, _settings.certificatePassword);
            var securityKey = new X509SecurityKey(certificate);
            var header = new JwtHeader(new SigningCredentials(securityKey, SecurityAlgorithms.RsaSha256))
            {
                { "x5c", new List<string> { Convert.ToBase64String(certificate.GetRawCertData()) } }
            };
            header.Remove("typ");
            header.Remove("kid");

            var dateTimeOffset = new DateTimeOffset(DateTime.Now);
            var payload = new JwtPayload
            {
                { "aud", _settings.maskinportenBaseAddress },
                { "scope", _settings.scope },
                { "iss",  _settings.clientId },
                { "exp", dateTimeOffset.ToUnixTimeSeconds() + 120 },
                { "iat", dateTimeOffset.ToUnixTimeSeconds() },
                { "jti", Guid.NewGuid().ToString() },
            };
            var securityToken = new JwtSecurityToken(header, payload);
            var handler = new JwtSecurityTokenHandler();
            return handler.WriteToken(securityToken);
        }

        private static FormUrlEncodedContent GetUrlEncodedContent(string assertion)
        {
            var formContent = new FormUrlEncodedContent(new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("grant_type", "urn:ietf:params:oauth:grant-type:jwt-bearer"),
                new KeyValuePair<string, string>("assertion", assertion),
            });

            return formContent;
        }