Connect to REST Data in JRuby

JRuby is a high-performance, stable, fully threaded Java implementation of the Ruby programming language. The CData JDBC Driver for REST makes it easy to integrate connectivity to live REST data in JRuby. This article shows how to create a simple JRuby app that connects to REST data, executes a query, and displays the results.

Configure a JDBC Connection to REST Data

Before creating the app, note the installation location for the JAR file for the JDBC Driver (typically C:\Program Files\CData\CData JDBC Driver for REST\lib).

JRuby natively supports JDBC, so you can easily connect to REST and execute SQL queries. Initialize the JDBC connection with the getConnection function of the java.sql.DriverManager class.

See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models REST APIs as bidirectional database tables and XML/JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

After setting the and providing any authentication values, set to "XML" or "JSON" and set to more closely match the data representation to the structure of your data.

The property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

• Document (default): Model a top-level, document view of your REST data. The data provider returns nested elements as aggregates of data.
• FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
• Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

See the Modeling REST Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the REST JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.rest.jar

Fill in the connection properties and copy the connection string to the clipboard.

Below is a typical JDBC connection string for REST:

jdbc:rest:DataModel=Relational;URI=C:/people.xml;Format=XML;

Create a JRuby App with Connectivity to REST Data

Create a new Ruby file (for example: RESTSelect.rb) and open it in a text editor. Copy the following code into your file:

require 'java'
require 'rubygems'
require 'C:/Program Files/CData/CData JDBC Driver for REST 2018/lib/cdata.jdbc.rest.jar'

url = "jdbc:rest:DataModel=Relational;URI=C:/people.xml;Format=XML;"
conn = java.sql.DriverManager.getConnection(url)
stmt = conn.createStatement
rs = stmt.executeQuery("SELECT [ personal.name.first ], [ personal.name.last ] FROM people")
while (rs.next) do
 puts rs.getString(1) + ' ' + rs.getString(2)
end

With the file completed, you are ready to display your REST data with JRuby. To do so, simply run your file from the command line:

jruby -S RESTSelect.rb

Writing SQL-92 queries to REST allows you to quickly and easily incorporate REST data into your own JRuby applications. Download a free trial today!