Add samples for Firebase database

Author: Eric Koleda

samples/FirebaseDB.gs

@@ -0,0 +1,59 @@
+/**
+ * This sample uses the Firebase Admin SDK to read from a Firebase Realtime
+ * Database.
+ * https://firebase.google.com/docs/reference/rest/database/
+ * https://firebase.google.com/docs/admin/setup
+ */
+
+var PROJECT_ID = '...';
+var PRIVATE_KEY = '...';
+var CLIENT_EMAIL = '...';
+
+/**
+ * Authorizes and makes a request to a Firebase Database.
+ */
+function run() {
+  var service = getService();
+  if (service.hasAccess()) {
+    var url = 'https://' + PROJECT_ID + '.firebaseio.com/.json?shallow=true';
+    var response = UrlFetchApp.fetch(url, {
+      headers: {
+        Authorization: 'Bearer ' + service.getAccessToken()
+      }
+    });
+    var result = JSON.parse(response.getContentText());
+    Logger.log(JSON.stringify(result, null, 2));
+  } else {
+    Logger.log(service.getLastError());
+  }
+}
+
+/**
+ * Reset the authorization state, so that it can be re-tested.
+ */
+function reset() {
+  var service = getService();
+  service.reset();
+}
+
+/**
+ * Configures the service.
+ */
+function getService() {
+  return OAuth2.createService('FirebaseDB')
+      // Set the endpoint URL.
+      .setTokenUrl('https://accounts.google.com/o/oauth2/token')
+
+      // Set the private key and issuer.
+      .setPrivateKey(PRIVATE_KEY)
+      .setIssuer(CLIENT_EMAIL)
+
+      // Set the property store where authorized tokens should be persisted.
+      .setPropertyStore(PropertiesService.getScriptProperties())
+
+      // Set the scope and additional Google-specific parameters.
+      .setScope([
+        'https://www.googleapis.com/auth/userinfo.email',
+        'https://www.googleapis.com/auth/firebase.database'
+      ]);
+}