Add Cloud Natural Language API sample.

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

Change-Id: I387cff7ac70c6f3c00a5b213527b4bd71c6c44dc

language/README.md

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+# Cloud Natural Language API Sample
+
+These samples demonstrate the use of the
+[Google Cloud Natural Language API](https://cloud.google.com/natural-language/docs/).
+
+`analyze.js` is a command-line program that demonstrates how different methods
+of the API can be called.
+
+## Setup
+
+Please follow the [Set Up Your Project](https://cloud-dot-devsite.googleplex.com/natural-language/docs/getting-started#set_up_your_project)
+steps in the Quickstart doc to create a project and enable the
+Cloud Natural Language API. Following those steps, make sure that you
+[Set Up a Service Account](https://cloud.google.com/natural-language/docs/common/auth#set_up_a_service_account),
+and export the following environment variable:
+
+```
+export GOOGLE_APPLICATION_CREDENTIALS=/path/to/your-project-credentials.json
+```
+
+## Run locally
+
+First install the needed dependencies.
+
+```
+npm install
+```
+
+To run:
+
+```
+node analyze.js <sentiment|entities|syntax> <text>
+```
+
+For example, the following command returns all entities found in the text:
+
+```
+node analyze.js entities "President Obama is speaking at the White House."
+```
+
+```
+{
+  "entities": [
+    {
+      "name": "Obama",
+      "type": "PERSON",
+      "metadata": {
+        "wikipedia_url": "http://en.wikipedia.org/wiki/Barack_Obama"
+      },
+      "salience": 0.84503114,
+      "mentions": [
+        {
+          "text": {
+            "content": "Obama",
+            "beginOffset": 10
+          }
+        }
+      ]
+    },
+    {
+      "name": "White House",
+      "type": "LOCATION",
+      "metadata": {
+        "wikipedia_url": "http://en.wikipedia.org/wiki/White_House"
+      },
+      "salience": 0.15496887,
+      "mentions": [
+        {
+          "text": {
+            "content": "White House",
+            "beginOffset": 35
+          }
+        }
+      ]
+    }
+  ],
+  "language": "en"
+}
+```

language/analyze.js

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+// 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, '  '));
+  });
+}

language/package.json

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+{
+  "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"
+}

test/language/analyze.test.js

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+// 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.
+
+'use strict';
+
+var analyzeExample = require('../../language/analyze');
+
+describe('language:analyze', function () {
+  it('should analyze sentiment in text', function (done) {
+    analyzeExample.main(
+      'sentiment',
+      'This gazinga pin is bad and it should feel bad',
+      function (err, result) {
+        assert(!err);
+        assert(result);
+        assert(result.documentSentiment);
+        assert(result.documentSentiment.polarity < 0);
+        done();
+      }
+    );
+  });
+  it('should analyze entities in text', function (done) {
+    analyzeExample.main(
+      'entities',
+      'Mark Twain is the author of a book called Tom Sawyer',
+      function (err, result) {
+        assert(!err);
+        assert(result);
+        assert(result.entities && result.entities.length);
+        assert(result.entities[0].name === 'Mark Twain');
+        assert(result.entities[0].type === 'PERSON');
+        done();
+      }
+    );
+  });
+  it('should analyze syntax in text', function (done) {
+    analyzeExample.main(
+      'syntax',
+      'Betty bought a bit of bitter butter. But she said, "This butter\'s ' +
+      'bitter! If I put it in my batter, it will make my batter bitter. If I ' +
+      'buy some better butter - better than this bitter butter - it will ' +
+      'make my batter better."',
+      function (err, result) {
+        assert(!err);
+        assert(result);
+        assert(result.sentences && result.sentences.length);
+        assert(result.tokens && result.tokens.length > 5);
+        done();
+      }
+    );
+  });
+});