Add Cloud Natural Language API sample. (#155)

* Add Cloud Natural Language API sample.

This sample makes a request to analyze the entities in text.

Change-Id: I387cff7ac70c6f3c00a5b213527b4bd71c6c44dc

* Update package.json

* Do it right this time

cloud-language/snippets/analyze.js

@@ -0,0 +1,171 @@
+// Copyright 2016, 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.
+
+/**
+ * @fileoverview Command-line program to demonstrate how to call different
+ * methods in Cloud Natural Language API.
+ *
+ * To run this example, install npm:
+ *   npm install
+ *
+ * You must also set up to authenticate with the Cloud APIs using your
+ * project's service account credentials. See the README for details.
+ *
+ * To run:
+ *   node analyze.js <sentiment|entities|syntax> <text>
+ *
+ * Here is an example:
+ *   node analyze.js entities "President Obama is speaking at the White House."
+ */
+'use strict';
+
+var google = require('googleapis');
+
+var languageScopes = ['https://www.googleapis.com/auth/cloud-platform'];
+
+/**
+ * Gets a client that is connected to the Google Cloud Natural Language API.
+ */
+function getLanguageService (callback) {
+  google.auth.getApplicationDefault(function (err, authClient) {
+    if (err) {
+      return callback(err);
+    }
+
+    // Depending on the environment that provides the default credentials
+    // (e.g. Compute Engine, App Engine), the credentials retrieved may
+    // require you to specify the scopes you need explicitly.
+    if (authClient.createScopedRequired && authClient.createScopedRequired()) {
+      authClient = authClient.createScoped(languageScopes);
+    }
+
+    // Load the discovery document for the natural language api service, using
+    // the acquired credentials.
+    console.log('Loading language service...');
+    google.discoverAPI({
+      url: 'https://language.googleapis.com/$discovery/rest',
+      version: 'v1beta1',
+      auth: authClient
+    }, function (err, languageService) {
+      if (err) {
+        return callback(err);
+      }
+      callback(null, languageService, authClient);
+    });
+  });
+}
+
+function analyzeSentiment (inputText, languageService, authClient, callback) {
+  languageService.documents.analyzeSentiment(
+    {
+      auth: authClient,
+      resource: { // Resource is used as the body for the API call.
+        document: {
+          content: inputText,
+          type: 'PLAIN_TEXT'
+        }
+      }
+    },
+    function (err, result) {
+      if (err) {
+        return callback(err);
+      }
+      callback(null, result);
+    });
+}
+
+function analyzeEntities (inputText, languageService, authClient, callback) {
+  languageService.documents.analyzeEntities(
+    {
+      auth: authClient,
+      resource: { // Resource is used as the body for the API call.
+        document: {
+          content: inputText,
+          type: 'PLAIN_TEXT'
+        },
+        encoding_type: 'UTF16'
+      }
+    },
+    function (err, result) {
+      if (err) {
+        return callback(err);
+      }
+      callback(null, result);
+    });
+}
+
+function analyzeSyntax (inputText, languageService, authClient, callback) {
+  languageService.documents.annotateText(
+    {
+      auth: authClient,
+      resource: { // Resource is used as the body for the API call.
+        document: {
+          content: inputText,
+          type: 'PLAIN_TEXT'
+        },
+        features: {
+          extract_syntax: 'TRUE'
+        },
+        encoding_type: 'UTF16'
+      }
+    },
+    function (err, result) {
+      if (err) {
+        return callback(err);
+      }
+      callback(null, result);
+    });
+}
+
+// Run the examples.
+exports.main = function (command, inputText, callback) {
+  getLanguageService(function (err, languageService, authClient) {
+    if (err) {
+      return callback(err);
+    }
+
+    var resultCallback = function (err, result) {
+      if (err) {
+        return callback(err);
+      }
+      callback(null, result);
+    };
+    if (command === 'sentiment') {
+      analyzeSentiment(inputText, languageService, authClient, resultCallback);
+    } else if (command === 'entities') {
+      analyzeEntities(inputText, languageService, authClient, resultCallback);
+    } else if (command === 'syntax') {
+      analyzeSyntax(inputText, languageService, authClient, resultCallback);
+    } else {
+      return callback(err);
+    }
+  });
+};
+
+if (require.main === module) {
+  var args = process.argv.slice(2);
+  if (args.length !== 2) {
+    console.log('Incorrect number of arguments. ' +
+                'Usage: node analyze.js <sentiment|entities|syntax> <text>');
+    process.exit(1);
+  }
+  if (['sentiment', 'entities', 'syntax'].indexOf(args[0]) === -1) {
+    console.log('Incorrect command. ' +
+                'Usage: node analyze.js <sentiment|entities|syntax> <text>');
+    process.exit(1);
+  }
+  exports.main(args[0], args[1], function (result) {
+    console.log(JSON.stringify(result, null, '  '));
+  });
+}

cloud-language/snippets/package.json

@@ -0,0 +1,18 @@
+{
+  "name": "cloud-natural-language-api-samples",
+  "version": "1.0.0",
+  "description": "Samples for using the Google Cloud Natural Language API.",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/GoogleCloudPlatform/nodejs-docs-samples.git"
+  },
+  "main": "analyze.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "dependencies": {
+    "googleapis": "^11.0.0"
+  },
+  "author": "Google, Inc.",
+  "license": "Apache-2.0"
+}