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Query Google Data Catalog Data from Node.js



The API Server exposes Web services that allow connectivity to your data. Use the OData endpoint of the CData API Server to execute CRUD queries to Google Data Catalog data from Node.js.

The CData API Server, when paired with the ADO.NET Provider for Google Data Catalog, exposes Google Data Catalog data (or data from any of 200+ other ADO.NET Providers) as an OData endpoint, which can be queried from Node.js using simple HTTP requests. This article shows how to use the API Server to request JSON-formatted Google Data Catalog data in Node.js.

Set Up the API Server

Follow the steps below to begin producing secure Google Data Catalog OData services:

Deploy

The API Server runs on your own server. On Windows, you can deploy using the stand-alone server or IIS. On a Java servlet container, drop in the API Server WAR file. See the help documentation for more information and how-tos.

The API Server is also easy to deploy on Microsoft Azure, Amazon EC2, and Heroku.

Connect to Google Data Catalog

After you deploy the API Server and the ADO.NET Provider for Google Data Catalog, provide authentication values and other connection properties needed to connect to Google Data Catalog by clicking Settings -> Connections and adding a new connection in the API Server administration console.

Google Data Catalog uses the OAuth authentication standard. Authorize access to Google APIs on behalf on individual users or on behalf of users in a domain.

Before connecting, specify the following to identify the organization and project you would like to connect to:

  • OrganizationId: The ID associated with the Google Cloud Platform organization resource you would like to connect to. Find this by navigating to the cloud console.

    Click the project selection drop-down, and select your organization from the list. Then, click More -> Settings. The organization ID is displayed on this page.

  • ProjectId: The ID associated with the Google Cloud Platform project resource you would like to connect to.

    Find this by navigating to the cloud console dashboard and selecting your project from the Select from drop-down. The project ID will be present in the Project info card.

When you connect, the OAuth endpoint opens in your default browser. Log in and grant permissions to the application to completes the OAuth process. For more information, refer to the OAuth section in the Help documentation.

You can then choose the Google Data Catalog entities you want to allow the API Server access to by clicking Settings -> Resources.

Authorize API Server Users

After determining the OData services you want to produce, authorize users by clicking Settings -> Users. The API Server uses authtoken-based authentication and supports the major authentication schemes. Access can also be restricted based on IP address; all IP addresses except the local machine are restricted by default. You can authenticate as well as encrypt connections with SSL.

Consume Google Data Catalog OData Feeds from Node.js

OData feeds are easy to work with in Node.js. You can use the HTTP client in Node.js to request JSON-formatted data from the API Server's OData endpoint. After making the request, you can construct the body of the response and call the JSON.parse() function to parse it into records.

The code below will make an authenticated request for Schemas data. The example URL below applies a simple filter that searches for records with a value of bigquery-public-data in the ProjectId column.

var http = require('http'); http.get({ protocol: "http:", hostname: "MyServer.com", port: MyPort, path: "/api.rsc/Schemas?$filter=" + encodeURIComponent("ProjectId eq 'bigquery-public-data'"), auth: 'MyUser:MyAuthtoken' }, function(res) { var body = ''; res.on('data', function(chunk) { body += chunk; }); res.on('end', function() { console.log(body); var jsonData = JSON.parse(body); }); }).on('error', function(e) { console.log("Error: ", e); });