Bridge JSON Connectivity with Apache NiFi

Apache NiFi supports powerful and scalable directed graphs of data routing, transformation, and system mediation logic. When paired with the CData JDBC Driver for JSON, NiFi can work with live JSON services. This article describes how to connect to and query JSON services from an Apache NiFi Flow.

With built-in optimized data processing, the CData JDBC driver offers unmatched performance for interacting with live JSON services. When you issue complex SQL queries to JSON, the driver pushes supported SQL operations, like filters and aggregations, directly to JSON and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze JSON services using native data types.

Connecting to JSON Services in Apache NiFi

1. Download the CData JDBC Driver for JSON installer, unzip the package, run the .exe file to install the driver.

2. Copy the CData JDBC Driver JAR file (and license file if it exists), cdata.jdbc.json.jar (and cdata.jdbc.json.lic), to the Apache NiFi lib subfolder, for example, C:\nifi-1.3.0-bin\nifi-1.3.0\lib.

   On Windows, the default location for the CData JDBC Driver is C:\Program Files\CData\CData JDBC Driver for JSON.

3. Start Apache NiFi by running the run-nifi.bat file in bin subfolder, for example, C:\nifi-1.3.0-bin\nifi-1.3.0\bin.

   (OR)

   Use the command prompt to navigate to the particular directory and run the run-nifi.bat file for example:

   cd C:\nifi-1.3.0-bin\nifi-1.3.0\bin
   .\run-nifi.bat
   

4. Navigate to the Apache NiFi UI in your web browser: It should be https://localhost:8443/nifi.

   Note: If users are utilizing an older version of Apache NiFi, they should access it via http://localhost:8080/nifi. In earlier versions, HTTP was the protocol employed. However, in the most recent version, HTTPS is the standard. By default, HTTP operates on port 8080, while HTTPS uses port 8443.

5. When accessing Apache NiFi via a URL, it prompts you to enter a username and password for login.

   👁 Enter Username and Password for login
   

   To retrieve login credentials, users should consult the 'App.log' file located within the log directory of their NiFi installation. This file typically contains the necessary details for accessing the NiFi interface.

   👁 Retrieve login credentials from App.log file
   
6. Right-click on the Nifi Flow's workspace and click "Controller Services" 👁 Configuring the Process Group
   
7. Click the button to create a new controller service. 👁 Creating a new Controller Service
   
8. In the Controller Services section, location the newly created "DBCPConnection Pool" and click the menu () >> Edit to configure the new connection. 👁 Configure the new DBCPConnection Pool
   

9. Fill in the properties:

   • Database Connection URL: jdbc:json:URI=C:/people.json;DataModel=Relational;
   • Database Driver Class Name: cdata.jdbc.json.JSONDriver
   • Database Driver Location(s): Path to your Apache NiFi's lib folder where the JAR files are present.

   Built-in Connection String Designer

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

   java -jar cdata.jdbc.json.jar
   

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

   See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models JSON APIs as bidirectional database tables and 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 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 JSON 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 JSON 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.

   👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
   
10. In the Controller Services section, locate the newly created DBCPConnection Pool and click the menu () >> Enable to enable the new connection.
11. In the "Enable Controller Service" window, set Scope to "Service and referencing components" 👁 Setting the scope of the Controller Service
    
12. To establish a connection and execute a select query, simply drag and drop the processor (indicated by the yellow highlight) into the workspace. 👁 Establish a connection and execute a select query
    
13. Select the 'ExecuteSQL' processor and click the 'Add' button to make it visible in the workspace. 👁 Select 'ExecuteSQL' and 'Add'
    
14. Double-click on the added processor (ExecuteSQL)to open the connection page. 👁 Click on ExecuteSQL processor to get redirected to the connection page
    
15. In the Properties section, fill in the required information. Make sure to set the Database Connection Pooling Service to match the DBCPConnectionPool that you have created, and set your desired SQL query that you want to get executed in the SQL select query section. 👁 Verify and test connection
    
16. Go to Relationships and make sure to select an option on how the component should proceed in case of success and failure of the execution process. 👁 Apply the connection
    
17. You can enable the ExecuteSQL component by either selecting it and clicking Enable on the Operation section, or by right-clicking it and selecting Enable. 👁 Click on the lightning button
    

Your JSON services is now available for use in Apache NiFi. For example, you can use the DBCPConnection Pool as the source for a QueryDatabaseTable processor (shown below).

Download a free, 30-day trial of the CData JDBC Driver for JSON and start working with your live JSON services in Apache NiFi. Reach out to our Support Team if you have any questions.