appengine/oauth2 sample (#168)

* appengine/oauth2 sample
* Also add minor formatting change to url fetch.
* check style helping too much.

.gitignore

@@ -26,3 +26,7 @@ dependency-reduced-pom.xml
 buildNumber.properties
 
 service-account.json
+
+# intellij
+.idea/
+*.iml

appengine/oauth2/.gitignore

@@ -0,0 +1,7 @@
+# Eclipse files
+.project
+.classpath
+.settings
+
+# Target folders
+target/

appengine/oauth2/README.md

@@ -0,0 +1,41 @@
+# Google App Engine Standard Environment
+## Oauth2 Sample
+
+This sample demonstrates using the Oauth2 apis to create an authenticaion filter.
+
+See the [Google App Engine standard environment documentation][ae-docs] for more
+detailed instructions.
+
+
+## Setup
+1. In the [Cloud Developers Console](https://cloud.google.com/console) > API Manager > Credentials,
+create a Oauth Client ID for a Web Application.  You will need to provide an authroized JavaScript
+origin.  Typically, https://projectID.appspot.com.
+1. Edit `src/main/webapp/index.html` and change `YOUR_CLIENT_ID_HERE.apps.googleusercontent.com` to
+Client ID from the prior step.
+
+## Running locally
+NOTE: The app can be run locally, but the Oauth2 APIs do not work with the development server.
+
+    $ mvn appengine:devserver
+
+## Deploying
+    $ mvn appengine:update -Dappengine.appId=YOUR-PROJECT-ID -Dappengine.version=SOME-VERSION
+
+1. Using your browser, visit `https://YOUR-PROJECT-ID.appspot.com`, click Sign In.
+
+1. The Sign In process will then request some text from your app, and then display it, if
+the id matches the list in `src/main/java/com/example/appengine/Oauth2Filter.java`.
+
+## Adding you to the list of valid users
+NOTE: Typically, you would use this for Service Accounts, but user accounts work as well.
+
+1. Enable logging by uncommenting the context.log line in
+`src/main/java/com/example/appengine/Oauth2Filter.java`, redeploy, and visit the page
+1. Look at the logs in [Cloud Developers Console](https://cloud.google.com/console) > Logs.
+
+1. Add the `tokenAudience` to the `allowedClients`.
+
+1. Deploy and visit the page again.
+
+[ae-docs]: https://cloud.google.com/appengine/docs/java/

appengine/oauth2/pom.xml

@@ -0,0 +1,60 @@
+<!--
+Copyright 2015 Google Inc. All Rights Reserved.
+
+ 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-oauth2</artifactId>
+
+  <properties>
+    <appengine.sdk.version>1.9.34</appengine.sdk.version>
+    <maven.compiler.target>1.7</maven.compiler.target>
+    <maven.compiler.source>1.7</maven.compiler.source>
+  </properties>
+  <parent>
+    <groupId>com.google.cloud</groupId>
+    <artifactId>doc-samples</artifactId>
+    <version>1.0.0</version>
+    <relativePath>../..</relativePath>
+  </parent>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-1.0-sdk</artifactId>
+      <version>${appengine.sdk.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>servlet-api</artifactId>
+      <type>jar</type>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <!-- for hot reload of the web application -->
+    <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
+    <plugins>
+      <plugin>
+        <groupId>com.google.appengine</groupId>
+        <artifactId>appengine-maven-plugin</artifactId>
+        <version>${appengine.sdk.version}</version>
+      </plugin>
+    </plugins>
+  </build>
+</project>

appengine/oauth2/src/main/java/com/example/appengine/HelloServlet.java

@@ -0,0 +1,37 @@
+/**
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * 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;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+// [START example]
+@SuppressWarnings("serial")
+public class HelloServlet extends HttpServlet {
+
+  @Override
+  public void doPost(final HttpServletRequest req, final HttpServletResponse resp)
+      throws IOException {
+    PrintWriter out = resp.getWriter();
+    out.print("Hello, world");  // simple hello world response
+  }
+}
+// [END example]

appengine/oauth2/src/main/java/com/example/appengine/Oauth2Filter.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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;
+
+import static com.google.appengine.api.utils.SystemProperty.environment;
+
+import com.google.appengine.api.oauth.OAuthRequestException;
+import com.google.appengine.api.oauth.OAuthService;
+import com.google.appengine.api.oauth.OAuthServiceFactory;
+import com.google.appengine.api.oauth.OAuthServiceFailureException;
+import com.google.appengine.api.users.User;
+import com.google.appengine.api.utils.SystemProperty;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+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.HttpServletResponse;
+
+/**
+ *  Filter to verify that request has a "Authorization: Bearer xxxx" header,
+ *  and check if xxxx is authorized to use this app.
+ *
+ *  Note - this is to demonstrate the OAuth2 APIs, as it is possible to lockdown some
+ *  of your app's URL's using cloud console by adding service accounts to the project.
+ */
+public class Oauth2Filter implements Filter {
+
+  private ServletContext context;
+
+  @Override
+  public void init(final FilterConfig config) throws ServletException {
+    this.context = config.getServletContext();
+  }
+
+  // [START oauth2]
+  @Override
+  public void doFilter(final ServletRequest servletReq, final ServletResponse servletResp,
+                             final FilterChain chain) throws IOException, ServletException {
+    final String scope = "https://www.googleapis.com/auth/userinfo.email";
+    Set<String> allowedClients = new HashSet<>();
+
+    HttpServletResponse resp = (HttpServletResponse) servletResp;
+
+    OAuthService oauth = OAuthServiceFactory.getOAuthService();
+
+    allowedClients.add("407408718192.apps.googleusercontent.com"); // list of client ids to allow
+    allowedClients.add("755878275993-j4k7emq6rlupctce1c28enpcrr50vfo1.apps.googleusercontent.com");
+
+    // Only check Oauth2 when in production, skip if run in development.
+    SystemProperty.Environment.Value env = environment.value();
+    if (env == SystemProperty.Environment.Value.Production) { // APIs only work in Production
+      try {
+        User user = oauth.getCurrentUser(scope);
+        String tokenAudience = oauth.getClientId(scope);
+
+          // The line below is commented out for privacy.
+//        context.log("tokenAudience: " + tokenAudience);   // Account we match
+
+        if (!allowedClients.contains(tokenAudience)) {
+          throw new OAuthRequestException("audience of token '" + tokenAudience
+              + "' is not in allowed list " + allowedClients);
+        }
+      } catch (OAuthRequestException ex) {
+        resp.sendError(HttpServletResponse.SC_NOT_FOUND);    // Not allowed
+        return;
+      } catch (OAuthServiceFailureException ex) {
+        resp.sendError(HttpServletResponse.SC_NOT_FOUND);    // some failure - reject
+        context.log("oauth2 failure", ex);
+        return;
+      }
+    }
+    chain.doFilter(servletReq, servletResp);  // continue processing
+  }
+  // [END oauth2]
+
+  @Override
+  public void destroy() { }
+
+}

appengine/oauth2/src/main/webapp/WEB-INF/appengine-web.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- [START_EXCLUDE] -->
+<!--
+  Copyright 2016 Google Inc. All Rights Reserved.
+  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.
+-->
+<!-- [END_EXCLUDE] -->
+<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
+  <application>YOUR-PROJECT-ID</application>
+  <version>YOUR-VERSION-ID</version>
+  <threadsafe>true</threadsafe>
+</appengine-web-app>

appengine/oauth2/src/main/webapp/WEB-INF/web.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"
+  xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
+  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
+  version="2.5">
+  <filter>
+    <filter-name>Oauth2Filter</filter-name>
+    <filter-class>com.example.appengine.Oauth2Filter</filter-class>
+  </filter>
+  <filter-mapping>
+    <filter-name>Oauth2Filter</filter-name>
+    <url-pattern>/hello</url-pattern>
+  </filter-mapping>
+
+  <servlet>
+    <servlet-name>hello</servlet-name>
+    <servlet-class>com.example.appengine.HelloServlet</servlet-class>
+  </servlet>
+  <servlet-mapping>
+    <servlet-name>hello</servlet-name>
+    <url-pattern>/hello</url-pattern>
+  </servlet-mapping>
+
+  <welcome-file-list>
+    <welcome-file>index.html</welcome-file>
+  </welcome-file-list>
+</web-app>

appengine/oauth2/src/main/webapp/index.html

@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta name="google-signin-scope" content="profile">
+    <meta name="google-signin-client_id" content="YOUR_CLIENT_ID_HERE.apps.googleusercontent.com" />
+
+    <script src="https://apis.google.com/js/platform.js" async defer></script>
+    <script>
+    function onSignIn(googleUser) {
+        // Useful data for your client-side scripts:
+        var access_token = googleUser.getAuthResponse().access_token;
+
+
+        var xhr = new XMLHttpRequest();
+        xhr.open('POST', '/hello');
+        xhr.setRequestHeader("Authorization", "Bearer "+access_token);
+        xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
+        xhr.onload = function() {
+            document.getElementById('response').innerHTML = xhr.responseText;
+            document.getElementById('me').style = "display:inline;";
+        };
+        xhr.onError = function() {
+            document.getElementById('response').innerHTML = "Error";
+            document.getElementById('me').style = "display:inline;";
+        };
+        xhr.send();
+    }
+    </script>
+</head>
+<body>
+<div class="g-signin2" data-onsuccess="onSignIn" data-theme="dark"></div>
+<div id="me" style="display: none;">
+    <h1><span id="response"></span></h1>
+</div>
+</body>
+</html>

appengine/urlfetch/pom.xml

@@ -19,12 +19,14 @@ Copyright 2015 Google Inc. All Rights Reserved.
   <version>1.0-SNAPSHOT</version>
   <groupId>com.example.appengine</groupId>
   <artifactId>appengine-URLFetch</artifactId>
+
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>doc-samples</artifactId>
     <version>1.0.0</version>
     <relativePath>../..</relativePath>
   </parent>
+
   <dependencies>
     <dependency>
       <groupId>javax.servlet</groupId>
@@ -38,6 +40,7 @@ Copyright 2015 Google Inc. All Rights Reserved.
       <version>20160212</version>
     </dependency>
   </dependencies>
+
   <build>
     <!-- for hot reload of the web application -->
     <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>

pom.xml

@@ -49,6 +49,7 @@
         <module>appengine/mailgun</module>
         <module>appengine/mailjet</module>
         <module>appengine/memcache</module>
+        <module>appengine/oauth2</module>
         <module>appengine/sendgrid</module>
         <module>appengine/static-files</module>
         <module>appengine/twilio</module>