Aplicativo de área de trabalho que chama APIs da Web: adquira um token usando nome de usuário e senha

Em seus aplicativos de desktop, você pode usar o fluxo de nome de usuário e senha, também conhecido como Resource Owner Password Credentials (ROPC), para adquirir um token silenciosamente.

Aviso

O fluxo de nome de usuário e senha não é recomendado , pois o aplicativo estará pedindo a um usuário sua senha diretamente, o que é um padrão inseguro. Para obter mais informações sobre os riscos e desafios que o fluxo ROPC representa, consulte "Qual é a solução para o crescente problema das senhas?".

Além disso, ao usar um nome de usuário e senha, os desenvolvedores abrem mão de uma série de coisas, incluindo:

• Principais princípios da identidade moderna - Uma senha pode ser roubada e repetida porque um segredo compartilhado pode ser intercetado.
• Autenticação multifator (MFA) - Os usuários não podem entrar porque não há interação.
• Recursos de logon único (SSO).

O fluxo de nome de usuário e senha também tem as seguintes restrições:

• O fluxo de nome de usuário e senha não é compatível com Acesso Condicional e autenticação multifator. Se seu aplicativo for executado em um locatário do Microsoft Entra em que o administrador exija autenticação multifator, como a maioria das organizações, você não poderá usar esse fluxo.
• Ele só funciona para contas corporativas e de estudante, não para contas pessoais da Microsoft.
• O fluxo está disponível na área de trabalho .NET e no .NET, mas não na UWP.

Usar um nome de usuário e senha é útil em alguns casos, como cenários de DevOps. No entanto, se você quiser usar um nome de usuário e senha em cenários interativos em que você fornece sua própria interface do usuário, considere se afastar dela.

O fluxo preferencial para adquirir um token silenciosamente no Windows é usar o agente de autenticação do Windows. Como alternativa, os desenvolvedores também podem usar o fluxo de código do dispositivo em dispositivos sem acesso ao navegador da Web.

Se estiver a criar uma aplicação de ambiente de trabalho que inicia sessão em utilizadores com identidades sociais utilizando o fluxo ROPC (Resource Owner Password Credentials), veja como iniciar sessão em utilizadores com identidades sociais utilizando o Azure AD B2C

Use o fluxo ROPC

.NET

IPublicClientApplicationcontém o método AcquireTokenByUsernamePassword.

O exemplo a seguir apresenta um caso simplificado.

static async Task GetATokenForGraph()
{
 string authority = "https://login.microsoftonline.com/contoso.com";
 string[] scopes = new string[] { "user.read" };
 IPublicClientApplication app;
 app = PublicClientApplicationBuilder.Create(clientId)
       .WithAuthority(authority)
       .Build();
 var accounts = await app.GetAccountsAsync();

 AuthenticationResult result = null;
 if (accounts.Any())
 {
  result = await app.AcquireTokenSilent(scopes, accounts.FirstOrDefault())
                    .ExecuteAsync();
 }
 else
 {
  try
  {
   var securePassword = new SecureString();
   foreach (char c in "dummy")        // you should fetch the password
    securePassword.AppendChar(c);  // keystroke by keystroke

   result = await app.AcquireTokenByUsernamePassword(scopes,
                                                    "joe@contoso.com",
                                                     securePassword)
                      .ExecuteAsync();
  }
  catch(MsalException)
  {
   // See details below
  }
 }
 Console.WriteLine(result.Account.Username);
}

O exemplo a seguir apresenta o caso mais atual, com explicações sobre o tipo de exceções que você pode obter e suas atenuações.

static async Task GetATokenForGraph()
{
 string authority = "https://login.microsoftonline.com/contoso.com";
 string[] scopes = new string[] { "user.read" };
 IPublicClientApplication app;
 app = PublicClientApplicationBuilder.Create(clientId)
                                   .WithAuthority(authority)
                                   .Build();
 var accounts = await app.GetAccountsAsync();

 AuthenticationResult result = null;
 if (accounts.Any())
 {
  result = await app.AcquireTokenSilent(scopes, accounts.FirstOrDefault())
                    .ExecuteAsync();
 }
 else
 {
  try
  {
   var securePassword = new SecureString();
   foreach (char c in "dummy")        // you should fetch the password keystroke
    securePassword.AppendChar(c);  // by keystroke

   result = await app.AcquireTokenByUsernamePassword(scopes,
                                                    "joe@contoso.com",
                                                    securePassword)
                    .ExecuteAsync();
  }
  catch (MsalUiRequiredException ex) when (ex.Message.Contains("AADSTS65001"))
  {
   // Here are the kind of error messages you could have, and possible mitigations

   // ------------------------------------------------------------------------
   // MsalUiRequiredException: AADSTS65001: The user or administrator has not consented to use the application
   // with ID '{appId}' named '{appName}'. Send an interactive authorization request for this user and resource.

   // Mitigation: you need to get user consent first. This can be done either statically (through the portal),
   /// or dynamically (but this requires an interaction with Azure AD, which is not possible with
   // the username/password flow)
   // Statically: in the portal by doing the following in the "API permissions" tab of the application registration:
   // 1. Click "Add a permission" and add all the delegated permissions corresponding to the scopes you want (for instance
   // User.Read and User.ReadBasic.All)
   // 2. Click "Grant/revoke admin consent for <tenant>") and click "yes".
   // Dynamically, if you are not using .NET (which does not have any Web UI) by
   // calling (once only) AcquireTokenInteractive.
   // remember that Username/password is for public client applications that is desktop/mobile applications.
   // If you are using .NET or don't want to call AcquireTokenInteractive, you might want to:
   // - use device code flow (See https://aka.ms/msal-net-device-code-flow)
   // - or suggest the user to navigate to a URL to consent: https://login.microsoftonline.com/common/oauth2/v2.0/authorize?client_id={clientId}&response_type=code&scope=user.read
   // ------------------------------------------------------------------------

   // ------------------------------------------------------------------------
   // ErrorCode: invalid_grant
   // SubError: basic_action
   // MsalUiRequiredException: AADSTS50079: The user is required to use multi-factor authentication.
   // The tenant admin for your organization has chosen to oblige users to perform multi-factor authentication.
   // Mitigation: none for this flow
   // Your application cannot use the Username/Password grant.
   // Like in the previous case, you might want to use an interactive flow (AcquireTokenInteractive()),
   // or Device Code Flow instead.
   // Note this is one of the reason why using username/password is not recommended;
   // ------------------------------------------------------------------------

   // ------------------------------------------------------------------------
   // ex.ErrorCode: invalid_grant
   // subError: null
   // Message = "AADSTS70002: Error validating credentials.
   // AADSTS50126: Invalid username or password
   // In the case of a managed user (user from an Azure AD tenant opposed to a
   // federated user, which would be owned
   // in another IdP through ADFS), the user has entered the wrong password
   // Mitigation: ask the user to re-enter the password
   // ------------------------------------------------------------------------

   // ------------------------------------------------------------------------
   // ex.ErrorCode: invalid_grant
   // subError: null
   // MsalServiceException: ADSTS50034: To sign into this application the account must be added to
   // the {domainName} directory.
   // or The user account does not exist in the {domainName} directory. To sign into this application,
   // the account must be added to the directory.
   // The user was not found in the directory
   // Explanation: wrong username
   // Mitigation: ask the user to re-enter the username.
   // ------------------------------------------------------------------------
  }
  catch (MsalServiceException ex) when (ex.ErrorCode == "invalid_request")
  {
   // ------------------------------------------------------------------------
   // AADSTS90010: The grant type is not supported over the /common or /consumers endpoints.
   // Please use the /organizations or tenant-specific endpoint.
   // you used common.
   // Mitigation: as explained in the message from Azure AD, the authority you use in the application needs
   // to be tenanted or otherwise "organizations". change the
   // "Tenant": property in the appsettings.json to be a GUID (tenant Id), or domain name (contoso.com)
   // if such a domain is registered with your tenant
   // or "organizations", if you want this application to sign-in users in any Work and School accounts.
   // ------------------------------------------------------------------------

  }
  catch (MsalServiceException ex) when (ex.ErrorCode == "unauthorized_client")
  {
   // ------------------------------------------------------------------------
   // AADSTS700016: Application with identifier '{clientId}' was not found in the directory '{domain}'.
   // This can happen if the application has not been installed by the administrator of the tenant or consented
   // to by any user in the tenant.
   // You may have sent your authentication request to the wrong tenant
   // Cause: The clientId in the appsettings.json might be wrong
   // Mitigation: check the clientId and the app registration
   // ------------------------------------------------------------------------
  }
  catch (MsalServiceException ex) when (ex.ErrorCode == "invalid_client")
  {
   // ------------------------------------------------------------------------
   // AADSTS70002: The request body must contain the following parameter: 'client_secret or client_assertion'.
   // Explanation: this can happen if your application was not registered as a public client application in Azure AD
   // Mitigation: in the Azure portal, edit the manifest for your application and set the `allowPublicClient` to `true`
   // ------------------------------------------------------------------------
  }
  catch (MsalServiceException)
  {
   throw;
  }

  catch (MsalClientException ex) when (ex.ErrorCode == "unknown_user_type")
  {
   // Message = "Unsupported User Type 'Unknown'. Please see https://aka.ms/msal-net-up"
   // The user is not recognized as a managed user, or a federated user. Azure AD was not
   // able to identify the IdP that needs to process the user
   throw new ArgumentException("U/P: Wrong username", ex);
  }
  catch (MsalClientException ex) when (ex.ErrorCode == "user_realm_discovery_failed")
  {
   // The user is not recognized as a managed user, or a federated user. Azure AD was not
   // able to identify the IdP that needs to process the user. That's for instance the case
   // if you use a phone number
   throw new ArgumentException("U/P: Wrong username", ex);
  }
  catch (MsalClientException ex) when (ex.ErrorCode == "unknown_user")
  {
   // the username was probably empty
   // ex.Message = "Could not identify the user logged into the OS. See https://aka.ms/msal-net-iwa for details."
   throw new ArgumentException("U/P: Wrong username", ex);
  }
  catch (MsalClientException ex) when (ex.ErrorCode == "parsing_wstrust_response_failed")
  {
   // ------------------------------------------------------------------------
   // In the case of a Federated user (that is owned by a federated IdP, as opposed to a managed user owned in an Azure AD tenant)
   // ID3242: The security token could not be authenticated or authorized.
   // The user does not exist or has entered the wrong password
   // ------------------------------------------------------------------------
  }
 }

 Console.WriteLine(result.Account.Username);
}

Para obter mais informações sobre todos os modificadores que podem ser aplicados ao AcquireTokenByUsernamePassword, consulte AcquireTokenByUsernamePasswordParameterBuilder.

Java

A extração a seguir é dos exemplos de código Java do MSAL.

 PublicClientApplication pca = PublicClientApplication.builder(clientId)
                .authority(authority)
                .build();

        //Get list of accounts from the application's token cache, and search them for the configured username
        //getAccounts() will be empty on this first call, as accounts are added to the cache when acquiring a token
        Set<IAccount> accountsInCache = pca.getAccounts().join();
        IAccount account = getAccountByUsername(accountsInCache, username);

        //Attempt to acquire token when user's account is not in the application's token cache
        IAuthenticationResult result = acquireTokenUsernamePassword(pca, scope, account, username, password);
        System.out.println("Account username: " + result.account().username());
        System.out.println("Access token:     " + result.accessToken());
        System.out.println("Id token:         " + result.idToken());
        System.out.println();

        accountsInCache = pca.getAccounts().join();
        account = getAccountByUsername(accountsInCache, username);

        //Attempt to acquire token again, now that the user's account and a token are in the application's token cache
        result = acquireTokenUsernamePassword(pca, scope, account, username, password);
        System.out.println("Account username: " + result.account().username());
        System.out.println("Access token:     " + result.accessToken());
        System.out.println("Id token:         " + result.idToken());
    }

    private static IAuthenticationResult acquireTokenUsernamePassword(PublicClientApplication pca,
                                                                      Set<String> scope,
                                                                      IAccount account,
                                                                      String username,
                                                                      String password) throws Exception {
        IAuthenticationResult result;
        try {
            SilentParameters silentParameters =
                    SilentParameters
                            .builder(scope)
                            .account(account)
                            .build();
            // Try to acquire token silently. This will fail on the first acquireTokenUsernamePassword() call
            // because the token cache does not have any data for the user you are trying to acquire a token for
            result = pca.acquireTokenSilently(silentParameters).join();
            System.out.println("==acquireTokenSilently call succeeded");
        } catch (Exception ex) {
            if (ex.getCause() instanceof MsalException) {
                System.out.println("==acquireTokenSilently call failed: " + ex.getCause());
                UserNamePasswordParameters parameters =
                        UserNamePasswordParameters
                                .builder(scope, username, password.toCharArray())
                                .build();
                // Try to acquire a token via username/password. If successful, you should see
                // the token and account information printed out to console
                result = pca.acquireToken(parameters).join();
                System.out.println("==username/password flow succeeded");
            } else {
                // Handle other exceptions accordingly
                throw ex;
            }
        }
        return result;
    }

macOS

O fluxo ROPC não é suportado no MSAL para macOS.

Node.js

Este extrato é dos exemplos de desenvolvimento do MSAL Node. No trecho de código a seguir, o nome de usuário e a senha são codificados apenas para fins ilustrativos. Isso deve ser evitado na produção. Em vez disso, recomenda-se uma interface do usuário básica solicitando que o usuário insira seu nome de usuário/senha.

const msal = require("@azure/msal-node");

const msalConfig = {
    auth: {
        clientId: "your_client_id_here",
        authority: "your_authority_here",
    }
};

const pca = new msal.PublicClientApplication(msalConfig);

// For testing, enter your username and password below.
// In production, replace this with a UI prompt instead.
const usernamePasswordRequest = {
    scopes: ["user.read"],
    username: "", // Add your username here
    password: "", // Add your password here
};

pca.acquireTokenByUsernamePassword(usernamePasswordRequest).then((response) => {
    console.log("acquired token by password grant");
}).catch((error) => {
    console.log(error);
});

Python

Este extrato é dos exemplos de desenvolvimento do MSAL Python.

# Create a preferably long-lived app instance which maintains a token cache.
app = msal.PublicClientApplication(
    config["client_id"], authority=config["authority"],
    # token_cache=...  # Default cache is in memory only.
                       # You can learn how to use SerializableTokenCache from
                       # https://msal-python.rtfd.io/en/latest/#msal.SerializableTokenCache
    )

# The pattern to acquire a token looks like this.
result = None

# Firstly, check the cache to see if this end user has signed in before
accounts = app.get_accounts(username=config["username"])
if accounts:
    logging.info("Account(s) exists in cache, probably with token too. Let's try.")
    result = app.acquire_token_silent(config["scope"], account=accounts[0])

if not result:
    logging.info("No suitable token exists in cache. Let's get a new one from AAD.")
    # See this page for constraints of Username Password Flow.
    # https://github.com/AzureAD/microsoft-authentication-library-for-python/wiki/Username-Password-Authentication
    result = app.acquire_token_by_username_password(
        config["username"], config["password"], scopes=config["scope"])

Próximos passos

Passe para o próximo artigo neste cenário, Chamar uma API da Web a partir do aplicativo da área de trabalho.