Pusher on App Engine sample

appengine/pom.xml

@@ -72,6 +72,7 @@
         <module>memcache</module>
         <module>multitenancy</module>
         <module>oauth2</module>
+        <module>pusher-chat</module>
         <module>requests</module>
         <module>search</module>
         <module>sendgrid</module>

appengine/pusher-chat/README.md

@@ -0,0 +1,47 @@
+# Pusher sample for Google App Engine
+
+This sample demonstrates how to use the [Pusher][pusher] on [Google App Engine][ae-docs].
+Pusher enables you to create public / private channels with presence information for real time messaging.
+This application demonstrates presence channels in Pusher using chat rooms.
+All users joining the chat room are authenticated using the `/authorize` endpoint.
+All users currently in the chat room receive updates of users joining / leaving the room.
+[Java HTTP library](https://github.com/pusher/pusher-http-java) is used for publishing messages to the channel
+and the [JS Websocket library](https://github.com/pusher/pusher-js) is used for subscribing.
+
+[pusher]: https://pusher.com
+[ae-docs]: https://cloud.google.com/appengine/docs/java/
+
+## Setup
+
+Install the [Google Cloud SDK](https://cloud.google.com/sdk/) and run:
+```
+   gcloud init
+```
+If this is your first time creating an App engine application:
+```
+   gcloud app create
+```
+
+#### Setup Pusher
+
+- Create a [Pusher] application and note down the `app_id`, `app_key`, `app_secret` and the cluster.
+- Update [appengine-web.xml](src/main/webapp/WEB-INF/appengine-web.xml) with these credentials.
+
+## Running locally
+
+```
+   mvn clean appengine:run
+```
+
+Access [http://localhost:8080](http://localhost:8080) via the browser, login and join the chat room.
+The chat window will contain a link you can use to join the room as a different user in another browser.
+You should now be able to view both the users within the chat application window and send messages to one another.
+
+## Deploying
+
+- Deploy the application to the project
+  ```
+       mvn clean appengine:deploy
+
+  ```
+  Access `https://YOUR_PROJECT_ID.appspot.com`

appengine/pusher-chat/pom.xml

@@ -0,0 +1,75 @@
+<!--
+Copyright 2017 Google Inc.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+<project>
+  <modelVersion>4.0.0</modelVersion>
+  <packaging>war</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <groupId>com.example.appengine</groupId>
+  <artifactId>appengine-pusher-chat</artifactId>
+
+  <parent>
+    <groupId>com.google.cloud</groupId>
+    <artifactId>appengine-doc-samples</artifactId>
+    <version>1.0.0</version>
+    <relativePath>..</relativePath>
+  </parent>
+
+  <properties>
+    <maven.compiler.source>1.7</maven.compiler.source>
+    <maven.compiler.target>1.7</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.pusher</groupId>
+      <artifactId>pusher-http-java</artifactId>
+      <version>1.0.0</version>
+    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>20.0</version>
+    </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <version>2.8.8</version>
+    </dependency>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>servlet-api</artifactId>
+      <version>2.5</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-1.0-sdk</artifactId>
+      <version>1.9.54</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <!-- for hot reload of the web application -->
+    <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
+    <plugins>
+      <plugin>
+        <groupId>com.google.cloud.tools</groupId>
+        <artifactId>appengine-maven-plugin</artifactId>
+        <version>1.3.1</version>
+      </plugin>
+    </plugins>
+  </build>
+</project>

appengine/pusher-chat/src/main/java/com/example/appengine/pusher/AuthorizeServlet.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.appengine.pusher;
+
+import com.google.appengine.api.users.User;
+import com.google.appengine.api.users.UserServiceFactory;
+import com.google.common.io.CharStreams;
+import com.pusher.rest.Pusher;
+import com.pusher.rest.data.PresenceUser;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.util.HashMap;
+import java.util.Map;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Authorization endpoint that is automatically triggered on `Pusher.subscribe` for private,
+ * presence channels. Successful authentication returns valid authorization token with user
+ * information.
+ *
+ * @see <a href="https://pusher.com/docs/authenticating_users">Pusher Authentication Docs</a>
+ */
+// [START pusher_authorize]
+public class AuthorizeServlet extends HttpServlet {
+
+  @Override
+  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+
+    // Instantiate a pusher connection
+    Pusher pusher = PusherService.getDefaultInstance();
+    // Get current logged in user credentials
+    User user = UserServiceFactory.getUserService().getCurrentUser();
+
+    // redirect to homepage if user is not authorized
+    if (user == null) {
+      response.sendRedirect("/");
+      return;
+    }
+    String currentUserId = user.getUserId();
+    String displayName = user.getNickname().replaceFirst("@.*", "");
+
+    String query = CharStreams.toString(request.getReader());
+    // socket_id, channel_name parameters are automatically set in the POST body of the request
+    // eg.socket_id=1232.12&channel_name=presence-my-channel
+    Map<String, String> data = splitQuery(query);
+    String socketId = data.get("socket_id");
+    String channelId = data.get("channel_name");
+
+    // Presence channels (presence-*) require user identification for authentication
+    Map<String, String> userInfo = new HashMap<>();
+    userInfo.put("displayName", displayName);
+
+    // Inject custom authentication code for your application here to allow /deny current request
+
+    String auth =
+        pusher.authenticate(socketId, channelId, new PresenceUser(currentUserId, userInfo));
+    // if successful, returns authorization in the format
+    //    {
+    //      "auth":"49e26cb8e9dde3dfc009:a8cf1d3deefbb1bdc6a9d1547640d49d94b4b512320e2597c257a740edd1788f",
+    //      "channel_data":"{\"user_id\":\"23423435252\",\"user_info\":{\"displayName\":\"John Doe\"}}"
+    //    }
+
+    response.getWriter().append(auth);
+  }
+
+  private static Map<String, String> splitQuery(String query) throws UnsupportedEncodingException {
+    Map<String, String> query_pairs = new HashMap<>();
+    String[] pairs = query.split("&");
+    for (String pair : pairs) {
+      int idx = pair.indexOf("=");
+      query_pairs.put(
+          URLDecoder.decode(pair.substring(0, idx), "UTF-8"),
+          URLDecoder.decode(pair.substring(idx + 1), "UTF-8"));
+    }
+    return query_pairs;
+  }
+}
+// [END pusher_authorize]

appengine/pusher-chat/src/main/java/com/example/appengine/pusher/ChatServlet.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.appengine.pusher;
+
+import com.google.appengine.api.users.User;
+import com.google.appengine.api.users.UserService;
+import com.google.appengine.api.users.UserServiceFactory;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/** Homepage of chat application, redirects user to login page if not authorized. */
+public class ChatServlet extends HttpServlet {
+
+  public static String getUriWithChatRoom(HttpServletRequest request, String chatRoom) {
+    try {
+      String query = "";
+      if (chatRoom != null) {
+        query = "room=" + chatRoom;
+      }
+      URI thisUri = new URI(request.getRequestURL().toString());
+      URI uriWithOptionalRoomParam =
+          new URI(
+              thisUri.getScheme(),
+              thisUri.getUserInfo(),
+              thisUri.getHost(),
+              thisUri.getPort(),
+              "/",
+              query,
+              "");
+      return uriWithOptionalRoomParam.toString();
+    } catch (URISyntaxException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Override
+  public void doGet(HttpServletRequest req, HttpServletResponse resp)
+      throws ServletException, IOException {
+    final UserService userService = UserServiceFactory.getUserService();
+    User currentUser = userService.getCurrentUser();
+    String room = req.getParameter("room");
+    // Show login link if user is not logged in.
+    if (currentUser == null) {
+      String loginUrl = userService.createLoginURL(getUriWithChatRoom(req, room));
+      resp.getWriter().println("<p>Please <a href=\"" + loginUrl + "\">sign in</a>.</p>");
+      return;
+    }
+
+    // user is already logged in
+    if (room != null) {
+      req.setAttribute("room", room);
+    }
+    getServletContext().getRequestDispatcher("/WEB-INF/view/chat.jsp").forward(req, resp);
+  }
+}

appengine/pusher-chat/src/main/java/com/example/appengine/pusher/PusherService.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.appengine.pusher;
+
+import com.pusher.rest.Pusher;
+
+// [START pusher_server_initialize]
+public abstract class PusherService {
+
+  public static final String APP_KEY = System.getenv("PUSHER_APP_KEY");
+  public static final String CLUSTER = System.getenv("PUSHER_CLUSTER");
+
+  private static final String APP_ID = System.getenv("PUSHER_APP_ID");
+  private static final String APP_SECRET = System.getenv("PUSHER_APP_SECRET");
+
+  private static Pusher instance;
+
+  static Pusher getDefaultInstance() {
+    if (instance != null) {
+      return instance;
+    } // Instantiate a pusher
+    Pusher pusher = new Pusher(APP_ID, APP_KEY, APP_SECRET);
+    pusher.setCluster(CLUSTER); // required, if not default mt1 (us-east-1)
+    pusher.setEncrypted(true); // optional, ensure subscriber also matches these settings
+    instance = pusher;
+    return pusher;
+  }
+}
+// [END pusher_server_initialize]