Build a PostgreSQL Interface for Gumroad Data using the CData JDBC Driver

There are a vast number of PostgreSQL clients available on the Internet. From standard Drivers to BI and Analytics tools, PostgreSQL is a popular interface for data access. Using our JDBC Drivers, you can now create PostgreSQL entry-points that you can connect to from any standard client.

To access Gumroad data as a PostgreSQL database, use the CData JDBC Driver for Gumroad and a JDBC foreign data wrapper (FDW). In this article, we compile the FDW, install it, and query Gumroad data from PostgreSQL Server.

Connect to Gumroad Data as a JDBC Data Source

To connect to Gumroad as a JDBC data source, you will need the following:

• Driver JAR path: The JAR is located in the lib subfolder of the installation directory.

• Driver class:

  cdata.jdbc.api.APIDriver
  

• JDBC URL: The URL must start with "jdbc:api:" and can include any of the connection properties in name-value pairs separated with semicolons.

  Using OAuth Authentication

  To authenticate to Gumroad and connect to your own data or to allow other users to connect to their data, you can use the OAuth 2.0 standard. This is the recommended authentication method.

  First you need to register an OAuth application with Gumroad. You can create an OAuth application by visiting your Gumroad account settings at https://app.gumroad.com/settings/advanced and navigating to the Applications section.

  After setting the following connection properties, you are ready to connect:

  • AuthScheme: Set this to OAuth.
  • InitiateOAuth: Set this to GETANDREFRESH. The CData API Profile for Gumroad will automatically walk through the OAuth process in order to obtain the access token.
  • OAuthClientID: Set this to the client_id that is specified in your app settings.
  • OAuthClientSecret: Set this to the client_secret that is specified in your app settings.
  • CallbackURL: Set this to the Redirect URI you specified in your app settings.

  Example connection string

  Profile=C:\profiles\Gumroad.apip;AuthScheme=OAuth;InitiateOAuth=GETANDREFRESH;OAuthClientId=your_client_id;OAuthClientSecret=your_client_secret;CallbackUrl=your_callback_url;
  

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.api.jar
  

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

  👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
  

  A typical JDBC URL is below:

  jdbc:api:Profile=C:\profiles\Gumroad.apip;AuthScheme=OAuth;InitiateOAuth=GETANDREFRESH;OAuthClientId=your_client_id;OAuthClientSecret=your_client_secret;CallbackUrl=your_callback_url;
  

Build the JDBC Foreign Data Wrapper

The Foreign Data Wrapper can be installed as an extension to PostgreSQL, without recompiling PostgreSQL. The jdbc2_fdw extension is used as an example (downloadable here).

1. Add a symlink from the shared object for your version of the JRE to /usr/lib/libjvm.so. For example:

   ln -s /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/libjvm.so /usr/lib/libjvm.so
   

2. Start the build:

   make install USE_PGXS=1
   

Query Gumroad Data as a PostgreSQL Database

After you have installed the extension, follow the steps below to start executing queries to Gumroad data:

1. Log into your database.
2. Load the extension for the database:

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for Gumroad:

   CREATE SERVER API 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.api.APIDriver',
   url 'jdbc:api:Profile=C:\profiles\Gumroad.apip;AuthScheme=OAuth;InitiateOAuth=GETANDREFRESH;OAuthClientId=your_client_id;OAuthClientSecret=your_client_secret;CallbackUrl=your_callback_url;',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.api.jar'); 
   

4. Create a user mapping for the username and password of a user known to the MySQL daemon.

   CREATE USER MAPPING for postgres SERVER API OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE customfields (
   customfields_id text,
   customfields_ text,
   customfields_ numeric) 
   SERVER API OPTIONS (
   table_name 'customfields');
   

You can now execute SELECT commands to Gumroad:

postgres=# SELECT * FROM customfields;