Gerenciador de callback de autorização de build

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

 <servlet>
   <servlet-name>PrintTasksTitles</servlet-name>
   <servlet-class>com.google.oauthsample.PrintTasksTitlesServlet</servlet-class>
 </servlet>

 <servlet-mapping>
   <servlet-name>PrintTasksTitles</servlet-name>
   <url-pattern>/</url-pattern>
 </servlet-mapping>

 <servlet>
   <servlet-name>OAuthCodeCallbackHandlerServlet</servlet-name>
   <servlet-class>com.google.oauthsample.OAuthCodeCallbackHandlerServlet</servlet-class>
 </servlet>

 <servlet-mapping>
   <servlet-name>OAuthCodeCallbackHandlerServlet</servlet-name>
   <url-pattern>/oauth2callback</url-pattern>
 </servlet-mapping>

</web-app>

package com.google.oauthsample;

import ...

/**
 * Simple sample Servlet which will display the tasks in the default task list of the user.
 */
@SuppressWarnings("serial")
public class PrintTasksTitlesServlet extends HttpServlet {

  /**
   * The OAuth Token DAO implementation, used to persist the OAuth refresh token.
   * Consider injecting it instead of using a static initialization. Also we are
   * using a simple memory implementation as a mock. Change the implementation to
   * using your database system.
   */
  public static OAuthTokenDao oauthTokenDao = new OAuthTokenDaoMemoryImpl();

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    // Getting the current user
    // This is using App Engine's User Service but you should replace this to
    // your own user/login implementation
    UserService userService = UserServiceFactory.getUserService();
    User user = userService.getCurrentUser();

    // If the user is not logged-in it is redirected to the login service, then back to this page
    if (user == null) {
      resp.sendRedirect(userService.createLoginURL(getFullRequestUrl(req)));
      return;
    }

    // Checking if we already have tokens for this user in store
    AccessTokenResponse accessTokenResponse = oauthTokenDao.getKeys(user.getEmail());

    // If we don't have tokens for this user
    if (accessTokenResponse == null) {
      OAuthProperties oauthProperties = new OAuthProperties();
      // Redirect to the Google OAuth 2.0 authorization endpoint
      resp.sendRedirect(new GoogleAuthorizationRequestUrl(oauthProperties.getClientId(),
          OAuthCodeCallbackHandlerServlet.getOAuthCodeCallbackHandlerUrl(req), oauthProperties
              .getScopesAsString()).build());
      return;
    }
  }

  /**
   * Construct the request's URL without the parameter part.
   *
   * @param req the HttpRequest object
   * @return The constructed request's URL
   */
  public static String getFullRequestUrl(HttpServletRequest req) {
    String scheme = req.getScheme() + "://";
    String serverName = req.getServerName();
    String serverPort = (req.getServerPort() == 80) ? "" : ":" + req.getServerPort();
    String contextPath = req.getContextPath();
    String servletPath = req.getServletPath();
    String pathInfo = (req.getPathInfo() == null) ? "" : req.getPathInfo();
    String queryString = (req.getQueryString() == null) ? "" : "?" + req.getQueryString();
    return scheme + serverName + serverPort + contextPath + servletPath + pathInfo + queryString;
  }
}

package com.google.oauthsample;

import com.google.api.client.auth.oauth2.draft10.AccessTokenResponse;

/**
 * Allows easy storage and access of authorization tokens.
 */
public interface OAuthTokenDao {

  /**
   * Stores the given AccessTokenResponse using the {@code username}, the OAuth
   * {@code clientID} and the tokens scopes as keys.
   *
   * @param tokens The AccessTokenResponse to store
   * @param userName The userName associated wit the token
   */
  public void saveKeys(AccessTokenResponse tokens, String userName);

  /**
   * Returns the AccessTokenResponse stored for the given username, clientId and
   * scopes. Returns {@code null} if there is no AccessTokenResponse for this
   * user and scopes.
   *
   * @param userName The username of which to get the stored AccessTokenResponse
   * @return The AccessTokenResponse of the given username
   */
  public AccessTokenResponse getKeys(String userName);
}

package com.google.oauthsample;

import com.google.api.client.auth.oauth2.draft10.AccessTokenResponse;
...

/**
 * Quick and Dirty memory implementation of {@link OAuthTokenDao} based on
 * HashMaps.
 */
public class OAuthTokenDaoMemoryImpl implements OAuthTokenDao {

  /** Object where all the Tokens will be stored */
  private static Map<String, AccessTokenResponse> tokenPersistance = new HashMap<String, AccessTokenResponse>();

  public void saveKeys(AccessTokenResponse tokens, String userName) {
    tokenPersistance.put(userName, tokens);
  }

  public AccessTokenResponse getKeys(String userName) {
    return tokenPersistance.get(userName);
  }
}

package com.google.oauthsample;

import ...

/**
 * Object representation of an OAuth properties file.
 */
public class OAuthProperties {

  public static final String DEFAULT_OAUTH_PROPERTIES_FILE_NAME = "oauth.properties";

  /** The OAuth 2.0 Client ID */
  private String clientId;

  /** The OAuth 2.0 Client Secret */
  private String clientSecret;

  /** The Google APIs scopes to access */
  private String scopes;

  /**
   * Instantiates a new OauthProperties object reading its values from the
   * {@code OAUTH_PROPERTIES_FILE_NAME} properties file.
   *
   * @throws IOException IF there is an issue reading the {@code propertiesFile}
   * @throws OauthPropertiesFormatException If the given {@code propertiesFile}
   *           is not of the right format (does not contains the keys {@code
   *           clientId}, {@code clientSecret} and {@code scopes})
   */
  public OAuthProperties() throws IOException {
    this(OAuthProperties.class.getResourceAsStream(DEFAULT_OAUTH_PROPERTIES_FILE_NAME));
  }

  /**
   * Instantiates a new OauthProperties object reading its values from the given
   * properties file.
   *
   * @param propertiesFile the InputStream to read an OAuth Properties file. The
   *          file should contain the keys {@code clientId}, {@code
   *          clientSecret} and {@code scopes}
   * @throws IOException IF there is an issue reading the {@code propertiesFile}
   * @throws OAuthPropertiesFormatException If the given {@code propertiesFile}
   *           is not of the right format (does not contains the keys {@code
   *           clientId}, {@code clientSecret} and {@code scopes})
   */
  public OAuthProperties(InputStream propertiesFile) throws IOException {
    Properties oauthProperties = new Properties();
    oauthProperties.load(propertiesFile);
    clientId = oauthProperties.getProperty("clientId");
    clientSecret = oauthProperties.getProperty("clientSecret");
    scopes = oauthProperties.getProperty("scopes");
    if ((clientId == null) || (clientSecret == null) || (scopes == null)) {
      throw new OAuthPropertiesFormatException();
    }
  }

  /**
   * @return the clientId
   */
  public String getClientId() {
    return clientId;
  }

  /**
   * @return the clientSecret
   */
  public String getClientSecret() {
    return clientSecret;
  }

  /**
   * @return the scopes
   */
  public String getScopesAsString() {
    return scopes;
  }

  /**
   * Thrown when the OAuth properties file was not at the right format, i.e not
   * having the right properties names.
   */
  @SuppressWarnings("serial")
  public class OAuthPropertiesFormatException extends RuntimeException {
  }
}

# Client ID and secret. They can be found in the APIs console.
clientId=1234567890.apps.googleusercontent.com
clientSecret=aBcDeFgHiJkLmNoPqRsTuVwXyZ
# API scopes. Space separated.
scopes=https://www.googleapis.com/auth/tasks

new GoogleAuthorizationRequestUrl(oauthProperties.getClientId(),
      OAuthCodeCallbackHandlerServlet.getOAuthCodeCallbackHandlerUrl(req), oauthProperties
          .getScopesAsString()).build()

package com.google.oauthsample;

import ...

/**
 * Servlet handling the OAuth callback from the authentication service. We are
 * retrieving the OAuth code, then exchanging it for a refresh and an access
 * token and saving it.
 */
@SuppressWarnings("serial")
public class OAuthCodeCallbackHandlerServlet extends HttpServlet {

  /** The name of the Oauth code URL parameter */
  public static final String CODE_URL_PARAM_NAME = "code";

  /** The name of the OAuth error URL parameter */
  public static final String ERROR_URL_PARAM_NAME = "error";

  /** The URL suffix of the servlet */
  public static final String URL_MAPPING = "/oauth2callback";

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    // Getting the "error" URL parameter
    String[] error = req.getParameterValues(ERROR_URL_PARAM_NAME);

    // Checking if there was an error such as the user denied access
    if (error != null && error.length > 0) {
      resp.sendError(HttpServletResponse.SC_NOT_ACCEPTABLE, "There was an error: \""+error[0]+"\".");
      return;
    }
    // Getting the "code" URL parameter
    String[] code = req.getParameterValues(CODE_URL_PARAM_NAME);

    // Checking conditions on the "code" URL parameter
    if (code == null || code.length == 0) {
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "The \"code\" URL parameter is missing");
      return;
    }
  }

  /**
   * Construct the OAuth code callback handler URL.
   *
   * @param req the HttpRequest object
   * @return The constructed request's URL
   */
  public static String getOAuthCodeCallbackHandlerUrl(HttpServletRequest req) {
    String scheme = req.getScheme() + "://";
    String serverName = req.getServerName();
    String serverPort = (req.getServerPort() == 80) ? "" : ":" + req.getServerPort();
    String contextPath = req.getContextPath();
    String servletPath = URL_MAPPING;
    String pathInfo = (req.getPathInfo() == null) ? "" : req.getPathInfo();
    return scheme + serverName + serverPort + contextPath + servletPath + pathInfo;
  }
}

package com.google.oauthsample;

import ...

/**
 * Servlet handling the OAuth callback from the authentication service. We are
 * retrieving the OAuth code, then exchanging it for a refresh and an access
 * token and saving it.
 */
@SuppressWarnings("serial")
public class OAuthCodeCallbackHandlerServlet extends HttpServlet {

  /** The name of the Oauth code URL parameter */
  public static final String CODE_URL_PARAM_NAME = "code";

  /** The name of the OAuth error URL parameter */
  public static final String ERROR_URL_PARAM_NAME = "error";

  /** The URL suffix of the servlet */
  public static final String URL_MAPPING = "/oauth2callback";
  /** O URL para redirecionar o usuário depois de processar o callback. Considere
   * salvar isso em um cookie antes de redirecionar os usuários para o URL de autorização
   * do Google se você tiver vários URLs possíveis para redirecionar as pessoas. */
  public static final String REDIRECT_URL = "/";

  /** A implementação do DAO do token OAuth. Considere injetá-lo em vez de usar
   * uma inicialização estática. Também estamos usando uma implementação de memória simples
   * como um modelo. Mude a implementação para usar seu sistema de banco de dados. */
  public static OAuthTokenDao oauthTokenDao = new OAuthTokenDaoMemoryImpl();

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    // Getting the "error" URL parameter
    String[] error = req.getParameterValues(ERROR_URL_PARAM_NAME);

    // Checking if there was an error such as the user denied access
    if (error != null && error.length > 0) {
      resp.sendError(HttpServletResponse.SC_NOT_ACCEPTABLE, "There was an error: \""+error[0]+"\".");
      return;
    }

    // Getting the "code" URL parameter
    String[] code = req.getParameterValues(CODE_URL_PARAM_NAME);

    // Checking conditions on the "code" URL parameter
    if (code == null || code.length == 0) {
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "The \"code\" URL parameter is missing");
      return;
    }
    // Cria o URL de solicitação de entrada
    String requestUrl = getOAuthCodeCallbackHandlerUrl(req);

    // Troca o código por tokens OAuth
    AccessTokenResponse accessTokenResponse = exchangeCodeForAccessAndRefreshTokens(code[0],
        requestUrl);

    // Recupera o usuário atual
    // Isso usa o serviço de usuário do App Engine, mas você precisa substituí-lo pela
    // sua própria implementação de usuário/login
    UserService userService = UserServiceFactory.getUserService();
    String email = userService.getCurrentUser().getEmail();

    // Salva os tokens
    oauthTokenDao.saveKeys(accessTokenResponse, email);

    resp.sendRedirect(REDIRECT_URL);
  }

  /**
   * Construct the OAuth code callback handler URL.
   *
   * @param req the HttpRequest object
   * @return The constructed request's URL
   */
  public static String getOAuthCodeCallbackHandlerUrl(HttpServletRequest req) {
    String scheme = req.getScheme() + "://";
    String serverName = req.getServerName();
    String serverPort = (req.getServerPort() == 80) ? "" : ":" + req.getServerPort();
    String contextPath = req.getContextPath();
    String servletPath = URL_MAPPING;
    String pathInfo = (req.getPathInfo() == null) ? "" : req.getPathInfo();
    return scheme + serverName + serverPort + contextPath + servletPath + pathInfo;
  }
  /**
   * Troca o código fornecido por uma troca e um token de atualização.
   *
   * @param code O código recebido do serviço de autorização
   * @param currentUrl O URL do callback
   * @param oauthProperties O objeto que contém a configuração do OAuth
   * @return O objeto que contém um token de acesso e de atualização
   * @throws IOException
   */
  public AccessTokenResponse exchangeCodeForAccessAndRefreshTokens(String code, String currentUrl)
      throws IOException {
    HttpTransport httpTransport = new NetHttpTransport();
    JacksonFactory jsonFactory = new JacksonFactory();

    // Carrega o arquivo de configuração do OAuth
    OAuthProperties oauthProperties = new OAuthProperties();

    return new GoogleAuthorizationCodeGrant(httpTransport, jsonFactory, oauthProperties
        .getClientId(), oauthProperties.getClientSecret(), code, currentUrl).execute();
  }
}

Arquivo OAuthCodeCallbackHandlerServlet.java

Observação: a implementação acima usa algumas bibliotecas do App Engine, que são usadas para simplificar. Se você estiver desenvolvendo para outra plataforma, implemente novamente a interface UserService, que processa a autenticação do usuário.

Ler e mostrar as tarefas do usuário

O usuário concedeu ao aplicativo acesso às tarefas. O aplicativo tem um token de atualização salvo no repositório de dados acessível pelo OAuthTokenDao. O servlet PrintTaskListsTitlesServlet agora pode usar esses tokens para acessar e mostrar as tarefas do usuário:

O código adicionado ao arquivo abaixo tem a sintaxe destacada, e o código já existente está esmaecido.

package com.google.oauthsample;

import ...

/**
 * Simple sample Servlet which will display the tasks in the default task list of the user.
 */
@SuppressWarnings("serial")
public class PrintTasksTitlesServlet extends HttpServlet {

  /**
   * The OAuth Token DAO implementation, used to persist the OAuth refresh token.
   * Consider injecting it instead of using a static initialization. Also we are
   * using a simple memory implementation as a mock. Change the implementation to
   * using your database system.
   */
  public static OAuthTokenDao oauthTokenDao = new OAuthTokenDaoMemoryImpl();

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    // Getting the current user
    // This is using App Engine's User Service but you should replace this to
    // your own user/login implementation
    UserService userService = UserServiceFactory.getUserService();
    User user = userService.getCurrentUser();

    // If the user is not logged-in it is redirected to the login service, then back to this page
    if (user == null) {
      resp.sendRedirect(userService.createLoginURL(getFullRequestUrl(req)));
      return;
    }

    // Checking if we already have tokens for this user in store
    AccessTokenResponse accessTokenResponse = oauthTokenDao.getKeys(user.getEmail());

    // If we don't have tokens for this user
    if (accessTokenResponse == null) {
      OAuthProperties oauthProperties = new OAuthProperties();
      // Redirect to the Google OAuth 2.0 authorization endpoint
      resp.sendRedirect(new GoogleAuthorizationRequestUrl(oauthProperties.getClientId(),
          OAuthCodeCallbackHandlerServlet.getOAuthCodeCallbackHandlerUrl(req), oauthProperties
              .getScopesAsString()).build());
      return;
    }
    // Mostra os títulos das listas de tarefas do usuário na resposta
    resp.setContentType("text/plain");
    resp.getWriter().append("Títulos de listas de tarefas para o usuário " + user.getEmail() + ":\n\n");
    printTasksTitles(accessTokenResponse, resp.getWriter());
  }

  /**
   * Construct the request's URL without the parameter part.
   *
   * @param req the HttpRequest object
   * @return The constructed request's URL
   */
  public static String getFullRequestUrl(HttpServletRequest req) {
    String scheme = req.getScheme() + "://";
    String serverName = req.getServerName();
    String serverPort = (req.getServerPort() == 80) ? "" : ":" + req.getServerPort();
    String contextPath = req.getContextPath();
    String servletPath = req.getServletPath();
    String pathInfo = (req.getPathInfo() == null) ? "" : req.getPathInfo();
    String queryString = (req.getQueryString() == null) ? "" : "?" + req.getQueryString();
    return scheme + serverName + serverPort + contextPath + servletPath + pathInfo + queryString;
  }
  /**
   * Usa a API Google Tasks para extrair uma lista de tarefas dos usuários na lista
   * padrão.
   *
   * @param accessTokenResponse O objeto AccessTokenResponse do OAuth 2.0
   *          que contém o token de acesso e um token de atualização.
   * @param output o gravador de stream de saída em que gravar os títulos das listas de tarefas
   * @return Uma lista dos títulos das tarefas dos usuários na lista de tarefas padrão.
   * @throws IOException
   */
  public void printTasksTitles(AccessTokenResponse accessTokenResponse, Writer output) throws IOException {

    // Initializing the Tasks service
    HttpTransport transport = new NetHttpTransport();
    JsonFactory jsonFactory = new JacksonFactory();
    OAuthProperties oauthProperties = new OAuthProperties();

    GoogleAccessProtectedResource accessProtectedResource = new GoogleAccessProtectedResource(
        accessTokenResponse.accessToken, transport, jsonFactory, oauthProperties.getClientId(),
        oauthProperties.getClientSecret(), accessTokenResponse.refreshToken);

    Tasks service = new Tasks(transport, accessProtectedResource, jsonFactory);

    // Using the initialized Tasks API service to query the list of tasks lists
    com.google.api.services.tasks.model.Tasks tasks = service.tasks.list("@default").execute();

    for (Task task : tasks.items) {
      output.append(task.title + "\n");
    }
  }
}

Arquivo PrintTasksTitlesServlet.java

O usuário vai aparecer com as tarefas:


  
  
As tarefas do usuário


Exemplo de aplicativo

O código para este aplicativo de exemplo pode ser baixado aqui. Confira.