add OAuth2 support for using Google Storage

rgerganov · Jul 3, 2011 · 02b8f3c · 02b8f3c
1 parent e912378
commit 02b8f3c
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diff --git a/src/main/java/com/lz2zg/qsl/servlet/Initializer.java b/src/main/java/com/lz2zg/qsl/servlet/Initializer.java
@@ -2,6 +2,8 @@
 
 import com.google.appengine.api.datastore.DatastoreService;
 import com.google.appengine.api.datastore.DatastoreServiceFactory;
+import com.google.appengine.api.memcache.MemcacheService;
+import com.google.appengine.api.memcache.MemcacheServiceFactory;
 import com.lz2zg.qsl.model.QslCard;
 import com.lz2zg.qsl.model.QslCardDao;
 import com.lz2zg.qsl.model.QslCardDaoImpl;
@@ -18,6 +20,9 @@ public void contextInitialized(ServletContextEvent sce) {
         QslCardDao dao = new QslCardDaoImpl(datastore);
         ServletContext context = sce.getServletContext();
         context.setAttribute("dao", dao);
+        MemcacheService memcacheService = MemcacheServiceFactory.getMemcacheService();
+        OAuth2ClientImpl oauth2client = new OAuth2ClientImpl(datastore, memcacheService);
+        context.setAttribute("oauth2client", oauth2client);
         //populateTestData(dao);
     }
 

diff --git a/src/main/java/com/lz2zg/qsl/servlet/OAuth2CallbackServlet.java b/src/main/java/com/lz2zg/qsl/servlet/OAuth2CallbackServlet.java
@@ -0,0 +1,34 @@
+package com.lz2zg.qsl.servlet;
+
+import java.io.IOException;
+import java.util.logging.Logger;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+public class OAuth2CallbackServlet extends HttpServlet {
+
+    static final Logger log = Logger.getLogger(OAuth2CallbackServlet.class.getName());
+    private static final long serialVersionUID = 1L;
+    OAuth2Client oauth2client;
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+        super.init(config);
+        ServletContext context = config.getServletContext();
+        oauth2client = (OAuth2Client) context.getAttribute("oauth2client");
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        String authCode = req.getParameter("code");
+        log.info("authCode: " + authCode);
+        oauth2client.fetchAccessAndRefreshTokens(authCode);
+        resp.setContentType("text/html");
+        resp.getWriter().println("<html><body>Authorization in Google Storage successful</body></html>");
+    }
+}
diff --git a/src/main/java/com/lz2zg/qsl/servlet/OAuth2Client.java b/src/main/java/com/lz2zg/qsl/servlet/OAuth2Client.java
@@ -0,0 +1,21 @@
+package com.lz2zg.qsl.servlet;
+
+
+public interface OAuth2Client {
+
+    String CLIENT_ID = "348460834037.apps.googleusercontent.com";
+
+    // this is useless until coupled with refresh token,
+    // so it safe to be hardcoded as a constant
+    String CLIENT_SECRET = "11DrV8S8kCglvYrxlG5Gt61Y";
+
+    String REDIRECT_URI = "http://localhost:8080/admin/oauth2callback";
+
+    String getAccessToken();
+
+    String getAccessToken(String refreshToken);
+
+    void fetchAccessAndRefreshTokens(String authCode);
+
+    String getRefreshToken();
+}
diff --git a/src/main/java/com/lz2zg/qsl/servlet/OAuth2ClientImpl.java b/src/main/java/com/lz2zg/qsl/servlet/OAuth2ClientImpl.java
@@ -0,0 +1,129 @@
+package com.lz2zg.qsl.servlet;
+
+import com.google.appengine.api.datastore.DatastoreService;
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.datastore.EntityNotFoundException;
+import com.google.appengine.api.datastore.Key;
+import com.google.appengine.api.datastore.KeyFactory;
+import com.google.appengine.api.memcache.Expiration;
+import com.google.appengine.api.memcache.MemcacheService;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLEncoder;
+import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class OAuth2ClientImpl implements OAuth2Client {
+
+    static final Logger log = Logger.getLogger(OAuth2ClientImpl.class.getName());
+    static final String OAUTH_URL = "https://accounts.google.com/o/oauth2/token";
+    final DatastoreService datastore;
+    final MemcacheService memcacheService;
+    final static String ENC = "UTF-8";
+    final static String ACCESS_TOKEN_KEY = "accessToken";
+
+    public OAuth2ClientImpl(DatastoreService datastore, MemcacheService memcacheService) {
+        this.datastore = datastore;
+        this.memcacheService = memcacheService;
+    }
+
+    @Override
+    public String getAccessToken() {
+        return (String) memcacheService.get(ACCESS_TOKEN_KEY);
+    }
+
+    @Override
+    public String getAccessToken(String refreshToken) {
+        try {
+            String data = String.format("client_id=%s&client_secret=%s&refresh_token=%s&grant_type=refresh_token",
+                    URLEncoder.encode(CLIENT_ID, ENC),
+                    URLEncoder.encode(CLIENT_SECRET, ENC),
+                    URLEncoder.encode(refreshToken, ENC));
+            String response = doPost(data);
+            log.info("Response after sending refreshToken: " + response);
+            String accessToken = parseStringField("access_token", response);
+            int expiresIn = parseIntField("expires_in", response);
+            memcacheService.put(ACCESS_TOKEN_KEY, accessToken, Expiration.byDeltaSeconds(expiresIn));
+            return accessToken;
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void fetchAccessAndRefreshTokens(String authCode) {
+        try {
+            String data = String.format("code=%s&client_id=%s&client_secret=%s&redirect_uri=%s&grant_type=authorization_code",
+                                            URLEncoder.encode(authCode, ENC),
+                                            URLEncoder.encode(CLIENT_ID, ENC),
+                                            URLEncoder.encode(CLIENT_SECRET, ENC),
+                                            URLEncoder.encode(REDIRECT_URI, ENC)); // what is this for?
+            String response = doPost(data);
+            log.info("Response after sending authCode: " + response);
+            String accessToken = parseStringField("access_token", response);
+            String refreshToken = parseStringField("refresh_token", response);
+            int expiresIn = parseIntField("expires_in", response);
+            memcacheService.put(ACCESS_TOKEN_KEY, accessToken, Expiration.byDeltaSeconds(expiresIn));
+            saveRefreshToken(refreshToken);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    Integer parseIntField(String field, String text) {
+        Pattern p = Pattern.compile(String.format("\"%s\":(\\d+)", field));
+        Matcher m = p.matcher(text);
+        if (m.find()) {
+            return Integer.parseInt(m.group(1));
+        }
+        return null;
+    }
+
+    String parseStringField(String field, String text) {
+        Pattern p = Pattern.compile(String.format("\"%s\":\"(.+?)\"", field));
+        Matcher m = p.matcher(text);
+        if (m.find()) {
+            return m.group(1);
+        }
+        return null;
+    }
+
+    String doPost(String data) throws IOException {
+        URL url = new URL(OAUTH_URL);
+        URLConnection conn = url.openConnection();
+        conn.setDoOutput(true);
+        conn.getOutputStream().write(data.getBytes(ENC));
+        conn.getOutputStream().flush();
+        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
+        String line = null;
+        String response = "";
+        while ((line = rd.readLine()) != null) {
+            response += line;
+        }
+        rd.close();
+        return response;
+    }
+
+    @Override
+    public String getRefreshToken() {
+        Key key = KeyFactory.createKey("refreshToken", "GoogleStorage");
+        try {
+            Entity entity = datastore.get(key);
+            return (String) entity.getProperty("value");
+        } catch (EntityNotFoundException e) {
+            return null;
+        }
+    }
+
+    void saveRefreshToken(String refreshToken) {
+        Key key = KeyFactory.createKey("refreshToken", "GoogleStorage");
+        Entity entity = new Entity(key);
+        entity.setProperty("value", refreshToken);
+        datastore.put(entity);
+    }
+}
diff --git a/src/main/java/com/lz2zg/qsl/servlet/OAuth2Filter.java b/src/main/java/com/lz2zg/qsl/servlet/OAuth2Filter.java
@@ -0,0 +1,70 @@
+package com.lz2zg.qsl.servlet;
+
+import java.io.IOException;
+import java.net.URLEncoder;
+import java.util.logging.Logger;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+
+public class OAuth2Filter implements Filter {
+
+    static final Logger log = Logger.getLogger(OAuth2ClientImpl.class.getName());
+    final static String GS_SCOPE = "https://www.googleapis.com/auth/devstorage.read_write";
+    OAuth2Client oauth2client;
+
+    @Override
+    public void init(FilterConfig config) throws ServletException {
+        ServletContext context = config.getServletContext();
+        oauth2client = (OAuth2Client) context.getAttribute("oauth2client");
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        HttpServletRequest req = (HttpServletRequest) request;
+        HttpServletResponse resp = (HttpServletResponse) response;
+        if (req.getRequestURL().toString().equals(OAuth2Client.REDIRECT_URI)) {
+            log.info("callback has been requested, pass forward");
+            chain.doFilter(request, response);
+            return;
+        }
+        String accessToken = oauth2client.getAccessToken();
+        if (accessToken != null) {
+            log.info("accessToken has been found");
+            req.setAttribute("accessToken", accessToken);
+            chain.doFilter(request, response);
+        } else {
+            String refreshToken = oauth2client.getRefreshToken();
+            if (refreshToken != null) {
+                log.info("getting accessToken using refreshToken");
+                accessToken = oauth2client.getAccessToken(refreshToken);
+                if (accessToken != null) {
+                    req.setAttribute("accessToken", accessToken);
+                    chain.doFilter(request, response);
+                } else {
+                    resp.setStatus(401);
+                    resp.setContentType("text/html");
+                    resp.getWriter().println("<html><body>Not Authorized</body></html>");
+                }
+            } else {
+                log.info("refreshToken not found, redirect to get authCode");
+                resp.sendRedirect(String.format("https://accounts.google.com/o/oauth2/auth?client_id=%s&redirect_uri=%s&scope=%s&response_type=code",
+                        OAuth2Client.CLIENT_ID,
+                        URLEncoder.encode(OAuth2Client.REDIRECT_URI, "UTF-8"),
+                        URLEncoder.encode(GS_SCOPE, "UTF-8")));
+            }
+        }
+    }
+
+    @Override
+    public void destroy() {
+    }
+}
diff --git a/src/main/java/com/lz2zg/qsl/servlet/UploadServlet.java b/src/main/java/com/lz2zg/qsl/servlet/UploadServlet.java
@@ -0,0 +1,21 @@
+package com.lz2zg.qsl.servlet;
+
+import java.io.IOException;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+public class UploadServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        String accessToken = (String) req.getAttribute("accessToken");
+        resp.setContentType("text/html");
+        resp.getWriter().println("Access token: " + accessToken);
+    }
+
+}
diff --git a/src/main/webapp/WEB-INF/appengine-web.xml b/src/main/webapp/WEB-INF/appengine-web.xml
@@ -2,4 +2,7 @@
 <appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
     <application>qsl-lz2zg</application>
     <version>1</version>
+    <system-properties>
+        <property name="java.util.logging.config.file" value="WEB-INF/logging.properties" />
+    </system-properties>
 </appengine-web-app>
diff --git a/src/main/webapp/WEB-INF/logging.properties b/src/main/webapp/WEB-INF/logging.properties
@@ -0,0 +1,13 @@
+# A default java.util.logging configuration.
+# (All App Engine logging is through java.util.logging by default).
+#
+# To use this configuration, copy it into your application's WEB-INF
+# folder and add the following to your appengine-web.xml:
+# 
+# <system-properties>
+#   <property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/>
+# </system-properties>
+#
+
+# Set the default logging level for all loggers to WARNING
+.level = INFO
diff --git a/src/main/webapp/WEB-INF/web.xml b/src/main/webapp/WEB-INF/web.xml
@@ -58,6 +58,17 @@
     <servlet-name>EditCardServlet</servlet-name>
     <url-pattern>/admin/edit</url-pattern>
   </servlet-mapping>
+
+  <servlet>
+    <servlet-name>OAuth2CallbackServlet</servlet-name>
+    <servlet-class>com.lz2zg.qsl.servlet.OAuth2CallbackServlet</servlet-class>
+  </servlet>
+
+  <servlet-mapping>
+    <servlet-name>OAuth2CallbackServlet</servlet-name>
+    <url-pattern>/admin/oauth2callback</url-pattern>
+  </servlet-mapping>
+
 <!--
   <security-constraint>
     <web-resource-collection>
@@ -78,6 +89,16 @@
     <filter-name>AuthenticationFilter</filter-name>
     <url-pattern>/admin/*</url-pattern>
   </filter-mapping>
+
+  <filter>
+    <filter-name>OAuth2Filter</filter-name>
+    <filter-class>com.lz2zg.qsl.servlet.OAuth2Filter</filter-class>
+  </filter>
+
+  <filter-mapping>
+    <filter-name>OAuth2Filter</filter-name>
+    <url-pattern>/admin/*</url-pattern>
+  </filter-mapping>
 
   <welcome-file-list>
     <welcome-file>main</welcome-file>