Add QuickstartOAuth2Sample

Author: jradcliff

.gitignore

@@ -22,3 +22,5 @@ __pycache__
 
 .flattened-pom.xml
 
+# Sample input files
+google-analytics-data/oauth2.keys.json

google-analytics-data/src/main/java/com/example/analytics/QuickstartOAuth2Sample.java

@@ -0,0 +1,254 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * 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.analytics;
+
+import com.google.analytics.data.v1beta.BetaAnalyticsDataClient;
+import com.google.analytics.data.v1beta.BetaAnalyticsDataSettings;
+import com.google.analytics.data.v1beta.DateRange;
+import com.google.analytics.data.v1beta.Dimension;
+import com.google.analytics.data.v1beta.Metric;
+import com.google.analytics.data.v1beta.Row;
+import com.google.analytics.data.v1beta.RunReportRequest;
+import com.google.analytics.data.v1beta.RunReportResponse;
+import com.google.api.client.http.GenericUrl;
+import com.google.api.client.http.HttpStatusCodes;
+import com.google.api.client.util.Key;
+import com.google.api.gax.core.FixedCredentialsProvider;
+import com.google.auth.oauth2.ClientId;
+import com.google.auth.oauth2.UserAuthorizer;
+import com.google.auth.oauth2.UserCredentials;
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.math.BigInteger;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.security.SecureRandom;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Google Analytics Data API sample quickstart application.
+ *
+ * <p>This application demonstrates the usage of the Analytics Data API using service account
+ * credentials.
+ *
+ * <p>Before you start the application, please review the comments starting with "TODO(developer)"
+ * and update the code to use correct values.
+ *
+ * <p>To run this sample using Maven:
+ *
+ * <pre>
+ * cd google-analytics-data
+ * mvn compile
+ * mvn exec:java -Dexec.mainClass="com.example.analytics.QuickstartOAuth2Sample"
+ * </pre>
+ */
+// [START analyticsdata_quickstart_oauth2]
+public class QuickstartOAuth2Sample {
+  // Scopes for the generated OAuth2 credentials. The list here only contains the Google Ads API
+  // scope, but you can add multiple scopes if you want to use the credentials for other Google
+  // APIs.
+  private static final ImmutableList<String> SCOPES =
+      ImmutableList.<String>builder()
+          .add("https://www.googleapis.com/auth/analytics.readonly")
+          .build();
+  private static final String OAUTH2_CALLBACK_BASE_URI = "http://127.0.0.1";
+
+  public static void main(String... args) throws Exception {
+    /**
+     * TODO(developer): Replace this variable with your Google Analytics 4 property ID before
+     * running the sample.
+     */
+    String propertyId = "YOUR-GA4-PROPERTY-ID";
+    sampleGetCredentialsAndRunReport(propertyId);
+  }
+
+  // This is an example snippet that calls the Google Analytics Data API and runs
+  // a simple report
+  // on the provided GA4 property id.
+  static void sampleGetCredentialsAndRunReport(String propertyId) throws Exception {
+    // Extracts the OAuth client information from the provided file.
+    ClientId parsedClient = ClientId.fromStream(new FileInputStream("./oauth2.keys.json"));
+    // Creates an anti-forgery state token as described here:
+    // https://developers.google.com/identity/protocols/OpenIDConnect#createxsrftoken
+    String state = new BigInteger(130, new SecureRandom()).toString(32);
+
+    // Creates an HTTP server that will listen for the OAuth2 callback request.
+    URI baseUri;
+    UserAuthorizer userAuthorizer;
+    AuthorizationResponse authorizationResponse = null;
+    try (SimpleCallbackServer simpleCallbackServer = new SimpleCallbackServer()) {
+      userAuthorizer =
+          UserAuthorizer.newBuilder()
+              .setClientId(parsedClient)
+              .setScopes(SCOPES)
+              // Provides an empty callback URI so that no additional suffix is added to the
+              // redirect. By default, UserAuthorizer will use "/oauth2callback" if this is
+              // either not set or set to null.
+              .setCallbackUri(URI.create(""))
+              .build();
+      baseUri = URI.create(OAUTH2_CALLBACK_BASE_URI + ":" + simpleCallbackServer.getLocalPort());
+      System.out.printf(
+          "Paste this url in your browser:%n%s%n",
+          userAuthorizer.getAuthorizationUrl(null, state, baseUri));
+
+      // Waits for the authorization code.
+      simpleCallbackServer.accept();
+      authorizationResponse = simpleCallbackServer.authorizationResponse;
+    }
+
+    if (authorizationResponse == null || authorizationResponse.code == null) {
+      throw new NullPointerException(
+          "OAuth2 callback did not contain an authorization code: " + authorizationResponse);
+    }
+
+    // Confirms that the state in the response matches the state token used to
+    // generate the
+    // authorization URL.
+    if (!state.equals(authorizationResponse.state)) {
+      throw new IllegalStateException("State does not match expected state");
+    }
+
+    // Exchanges the authorization code for credentials and print the refresh token.
+    UserCredentials userCredentials =
+        userAuthorizer.getCredentialsFromCode(authorizationResponse.code, baseUri);
+    System.out.printf("Successfully obtained user credentials for scope(s): %s%n", SCOPES);
+
+    // Constructs a BetaAnalyticsDataClient using the UserCredentials obtained.
+    try (BetaAnalyticsDataClient analyticsData =
+        BetaAnalyticsDataClient.create(
+            BetaAnalyticsDataSettings.newBuilder()
+                .setCredentialsProvider(FixedCredentialsProvider.create(userCredentials))
+                .build())) {
+      RunReportRequest request =
+          RunReportRequest.newBuilder()
+              .setProperty("properties/" + propertyId)
+              .addDimensions(Dimension.newBuilder().setName("city"))
+              .addMetrics(Metric.newBuilder().setName("activeUsers"))
+              .addDateRanges(DateRange.newBuilder().setStartDate("2020-03-31").setEndDate("today"))
+              .build();
+
+      // Make the request.
+      RunReportResponse response = analyticsData.runReport(request);
+
+      System.out.println("Report result:");
+      // Iterate through every row of the API response.
+      for (Row row : response.getRowsList()) {
+        System.out.printf(
+            "%s, %s%n", row.getDimensionValues(0).getValue(), row.getMetricValues(0).getValue());
+      }
+    }
+  }
+
+  /** Basic server that listens for the OAuth2 callback. */
+  private static class SimpleCallbackServer extends ServerSocket {
+
+    private AuthorizationResponse authorizationResponse;
+
+    SimpleCallbackServer() throws IOException {
+      // Passes a port # of zero so that a port will be automatically allocated.
+      super(0);
+    }
+
+    /**
+     * Blocks until a connection is made to this server. After this method completes, the
+     * authorizationResponse of this server will be set, provided the request line is in the
+     * expected format.
+     */
+    @Override
+    public Socket accept() throws IOException {
+      Socket socket = super.accept();
+
+      try (BufferedReader in =
+          new BufferedReader(
+              new InputStreamReader(socket.getInputStream(), StandardCharsets.UTF_8))) {
+        String callbackRequest = in.readLine();
+        // Uses a regular expression to extract the request line from the first line of
+        // the
+        // callback request, e.g.:
+        // GET /?code=AUTH_CODE&state=XYZ&scope=https://www.googleapis.com/auth/adwords
+        // HTTP/1.1
+        Pattern pattern = Pattern.compile("GET +([^ ]+)");
+        Matcher matcher = pattern.matcher(Strings.nullToEmpty(callbackRequest));
+        if (matcher.find()) {
+          String relativeUrl = matcher.group(1);
+          authorizationResponse = new AuthorizationResponse(OAUTH2_CALLBACK_BASE_URI + relativeUrl);
+        }
+        try (Writer outputWriter = new OutputStreamWriter(socket.getOutputStream())) {
+          outputWriter.append("HTTP/1.1 ");
+          outputWriter.append(Integer.toString(HttpStatusCodes.STATUS_CODE_OK));
+          outputWriter.append(" OK\n");
+          outputWriter.append("Content-Type: text/html\n\n");
+
+          outputWriter.append("<b>");
+          if (authorizationResponse.code != null) {
+            outputWriter.append("Authorization code was successfully retrieved.");
+          } else {
+            outputWriter.append("Failed to retrieve authorization code.");
+          }
+          outputWriter.append("</b>");
+          outputWriter.append("<p>Please check the console output from <code>");
+          outputWriter.append(QuickstartOAuth2Sample.class.getSimpleName());
+          outputWriter.append("</code> for further instructions.");
+        }
+      }
+      return socket;
+    }
+  }
+
+  /** Response object with attributes corresponding to OAuth2 callback parameters. */
+  static class AuthorizationResponse extends GenericUrl {
+
+    /** The authorization code to exchange for an access token and (optionally) a refresh token. */
+    @Key String code;
+
+    /** Error from the request or from the processing of the request. */
+    @Key String error;
+
+    /** State parameter from the callback request. */
+    @Key String state;
+
+    /**
+     * Constructs a new instance based on an absolute URL. All fields annotated with the {@link Key}
+     * annotation will be set if they are present in the URL.
+     *
+     * @param encodedUrl absolute URL with query parameters.
+     */
+    public AuthorizationResponse(String encodedUrl) {
+      super(encodedUrl);
+    }
+
+    @Override
+    public String toString() {
+      return MoreObjects.toStringHelper(getClass())
+          .add("code", code)
+          .add("error", error)
+          .add("state", state)
+          .toString();
+    }
+  }
+}
+// [END analyticsdata_quickstart_oauth2]

google-analytics-data/src/main/java/com/example/analytics/QuickstartSample.java

@@ -45,7 +45,7 @@ public static void main(String... args) throws Exception {
      * TODO(developer): Replace this variable with your Google Analytics 4 property ID before
      * running the sample.
      */
-    String propertyId = "355158046";
+    String propertyId = "YOUR-GA4-PROPERTY-ID";
     sampleRunReport(propertyId);
   }