Consume RabbitMQ OData Feeds in PowerBuilder

The CData API Server produces secure feeds of RabbitMQ data that you can consume in PowerBuilder DataWindows. The API Server supports the major Web services, including OData, Atom, JSON, HTML, CSV, TSV, and RSS. It also supports the major authentication schemes and SSL.

This article shows how to create a DataWindow that uses the CData API Server to retrieve data.

Set Up the API Server

Follow the steps below to begin producing secure RabbitMQ 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 RabbitMQ

After you deploy the API Server, provide authentication values and other connection properties needed to connect to RabbitMQ by clicking Settings -> Connections and adding a new connection in the API Server administration console.

About RabbitMQ Management HTTP API

RabbitMQ is an open-source message broker that supports multiple messaging protocols. The RabbitMQ Management HTTP API provides HTTP-based access to management and monitoring data for a RabbitMQ server. The API exposes information about virtual hosts, exchanges, queues, bindings, connections, channels, consumers, users, permissions, policies, and cluster-wide statistics.

The Management plugin must be enabled on the RabbitMQ server for the HTTP API to be available. By default, the management interface listens on port 15672.

Using Basic Authentication

RabbitMQ Management HTTP API uses HTTP Basic authentication. You must supply the username and password of a RabbitMQ management user.

To enable access to the management API:

1. Ensure the RabbitMQ Management plugin is enabled on your server (rabbitmq-plugins enable rabbitmq_management).
2. Use an existing management user or create one with the appropriate management tag (management, policymaker, monitoring, or administrator).
3. Note the full base URL of your RabbitMQ Management HTTP API (e.g., http://localhost:15672).

After configuring your RabbitMQ server, set the following connection properties to connect:

• AuthScheme: Set this to Basic.
• URL: Set this to the base URL of your RabbitMQ Management HTTP API (e.g., http://localhost:15672).
• User: Set this to your RabbitMQ management username (e.g., guest).
• Password: Set this to your RabbitMQ management password.

Example connection string:

Profile=C:\profiles\RabbitMQ.apip;AuthScheme=Basic;URL=http://localhost:15672;User=guest;Password=guest;

Available Tables

The RabbitMQ profile provides access to the following tables:

• Overview - Cluster-wide statistics and information about the RabbitMQ node
• Nodes - Information about individual nodes in the RabbitMQ cluster
• NodeMemory - Detailed memory usage breakdown for a specific cluster node
• Connections - List of all open AMQP connections to the broker
• Channels - List of all open AMQP channels across all connections
• Consumers - List of all consumers registered across all queues
• Exchanges - List of exchanges declared across all virtual hosts
• Queues - List of queues declared across all virtual hosts
• Bindings - List of all bindings between exchanges and queues
• VirtualHosts - List of virtual hosts configured on the broker
• VhostPermissions - User permissions within a specific virtual host
• Users - List of all RabbitMQ users
• Permissions - Permission records for all users across all virtual hosts
• TopicPermissions - Topic-level permission records for all users
• Policies - List of policies applied to queues and exchanges in virtual hosts
• OperatorPolicies - List of operator policies applied to queues in virtual hosts
• Parameters - List of component parameters (e.g., federation, shovel) per virtual host
• GlobalParameters - List of global parameters that apply across all virtual hosts
• VhostLimits - Resource limits configured for specific virtual hosts
• UserLimits - Resource limits configured for specific users
• FeatureFlags - List of feature flags and their enabled/disabled state on the node
• DeprecatedFeatures - List of deprecated features and their usage state
• AuthAttempts - Authentication attempt statistics for the node
• ClusterName - The name of the RabbitMQ cluster
• WhoAmI - Information about the currently authenticated management user
• ExchangeBindingsSource - Bindings for which a specific exchange is the source
• ExchangeBindingsDestination - Bindings for which a specific exchange is the destination
• QueueBindings - Bindings for a specific queue within a virtual host

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

Additionally, click Settings -> Server and change the following settings for compatibility with PowerBuilder:

• Default Format: Select XML (Atom) in the menu.
• Default Version: Select 2.0 in the menu.

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; by default, only connections to the local machine are allowed. You can authenticate as well as encrypt connections with SSL.

Create a Profile for RabbitMQ

Follow the steps below to use the Database Painter tool to create a database profile for the OData API of the API Server. In the Database Painter, you can graphically manipulate data as well as execute SQL queries.

1. Click Tools -> Database Painter.
2. Right-click the OData node and click New Profile.
3. In the Database Profile Setup dialog, enter the following:
   • Profile Name: Enter a user-friendly name for the profile.
   • URI: Enter the URL to the OData endpoint of the API Server. This URL will resemble the one below:

     http://MyServer:8080/api.rsc

   • Supply User Id and Password: Click this option to use HTTP Basic authentication. Note that the API Server also supports Windows authentication.
   • User Id: Enter the name of an user in the API Server.
   • Password: Enter the authtoken of an user in the API Server.
   
4. To view and modify a table, right-click a table and then click Edit Data -> Grid.

Using RabbitMQ Data with PowerBuilder Controls

You can use standard PowerBuilder objects to connect to OData feeds and execute queries. The following example shows how to retrieve RabbitMQ data into a DataWindow.

You can add the following code to the open method:

SQLCA.DBMS = "ODT"
SQLCA.DBParm = "ConnectString='URI=http://MyServer:8080/api.rsc;UID=MyAPIUser;PWD=MyAuthtoken'";
CONNECT USING SQLCA;
dw_authattempts.SetTransObject(SQLCA);
dw_authattempts.Retrieve();