Creating a connector to an external data source
To create a connector, you need a data source to query, and a server that supports REST endpoints to query it from. On that foundation, you can build the functionality that takes requests from the i2® Connect gateway, retrieves data from the source, and returns it to the gateway in a shape that is ready for conversion to i2 Analyze records.
The easiest approach to writing a connector is to start by transferring data from the external source to the i2 Analyze server - and then to the client - with as few complications as possible. When you have that mechanism, you can use it as a base from which to develop the more complex services that you want to implement.
Note: The example connectors at https://github.com/IBM-i2/Analyze-Connect contain services that between them demonstrate several aspects of connector development. As you read this documentation, it is helpful also to read the source code for those examples.