/// <summary>
/// Finds the access token for the specified user in the cache or via the refresh token by renewing it.
/// </summary>
/// <param name="userId">The id of the user</param>
/// <returns>Either the access token if successful or default if something went wrong
/// (The user may need to login again if the refresh token in the key vault was invalid.)</returns>
public async Task <string?> GetAccessTokenAsync(string userId)
{
try
{
//
// Get the refresh token
//
var oldRefreshToken = _secretManager.GetSecret(userId);
// No refresh token found -> User needs to login first
if (oldRefreshToken is null)
{
return(default);
/// <summary>
/// Validates the signature of the slack request.
/// </summary>
/// <param name="body">The request body</param>
/// <param name="headers">The request headers</param>
/// <returns>True if the signature is valid</returns>
private bool IsValidSignature(string body, IHeaderDictionary headers)
{
var timestamp = headers["X-Slack-Request-Timestamp"];
var signature = headers["X-Slack-Signature"];
var signingSecret = _secretManager.GetSecret("Slack-SigningSecret");
var encoding = new UTF8Encoding();
using var hmac = new HMACSHA256(encoding.GetBytes(signingSecret));
var hash = hmac.ComputeHash(encoding.GetBytes($"v0:{timestamp}:{body}"));
var ownSignature = $"v0={BitConverter.ToString(hash).Replace("-", "", StringComparison.CurrentCulture).ToLower()}";
return(ownSignature.Equals(signature, StringComparison.CurrentCulture));
}
public CommandController(
IConfiguration configuration,
IHttpClientFactory factory,
IDataProtectionProvider provider,
ISecretManager secretManager,
ICosmosManager cosmosManager,
ITokenManager tokenManager,
ITCManager dataManager
)
{
#pragma warning disable CA2208 // Instantiate argument exceptions correctly
if (provider is null)
{
var message = "IDataProtectionProvider";
throw new ArgumentNullException(message);
}
if (factory is null)
{
throw new ArgumentNullException("IHttpClientFactory");
}
if (secretManager is null)
{
throw new ArgumentNullException("ISecretManager");
}
#pragma warning restore CA2208 // Instantiate argument exceptions correctly
_configuration = configuration;
_protector = provider.CreateProtector("UUIDProtector");
_secretManager = secretManager;
_cosmosManager = cosmosManager;
_httpClient = factory.CreateClient("BotClient");
_httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", _secretManager.GetSecret("Slack-SlackbotOAuthAccessToken"));
_tokenManager = tokenManager;
_tcDataManager = dataManager;
_commandHandler = new CommandHandler(_protector, _cosmosManager, _secretManager, _tokenManager, _tcDataManager);
}
