What is the proper way to authenticate with Model REST API's?

Question

The Platform SDK documentation talks about creating Model REST API's to read and write from data models.

Here is a link to that section of the documentation:
https://devnet.onenetwork.com/oms/apps/DeveloperNetwork/www/docs/guides/SdkUsersGuide/help/index.html#RestAPIs

I set up a Model REST API per the steps in the documentation. However, when I attempt to POST data to the new Model REST API, I get a 401 Unauthorized response code.

What are the proper headers and authentication to send when connecting to a Model REST API?

(If it matters, I want to connect to a Model API from the Java class of a custom interface. Specifically I am calling the "executeAction" method for writing data.)

Thank you!

Matt Nutsch · Accepted Answer

Thanks to Yang Cao for explaining the commonly used method for inserting data into Models. (The Model API documentation mentions REST and gives a URL, but the SDK has a Java method for interacting with Models.)

There is a Java Class called ModelDataService. To write data to models from Java, we typically call the method [ModelDataService].write();

Here is a full example (parsing JSON and inserting into the Model 'Item'):

        //Read values from the POST body.
        JSONObject obj = new JSONObject(contents); //convert the JSON string into an object
        String enterprise = obj.getString("enterprise");
        String itemName = obj.getString("itemName");
        Float price = (float) obj.getDouble("price");
        Integer valueChainID = obj.getInt("valueChainID");

        //Initialize a ModelList
        ModelList<Item> modelList = new ModelList<Item>();
        modelList.setActionName("PLT.InsertOrUpdate");
        modelList.setValueChainId(valueChainID);

        //Initialize an Item using data from the POST body.
        Item newItem = new Item();
        newItem.setName(itemName);
        newItem.setValueChainId(valueChainID);
        newItem.setPriceAmount(price);
        newItem.setEnterpriseName(enterprise);

        List<Item> items = new ArrayList<Item>();
        items.add(newItem);

        //Add the Item to the ModelList
        modelList.getModels().addAll(items);

        //Write the ModelList to the database
        ModelDataService mds = Services.get(ModelDataService.class);
        ModelList returnedList = mds.write(modelList, ctx);

        if (returnedList.getListError() != null || returnedList.getErrors().size() > 0) {
          throw new Exception("Unable to create catalog for esg companies : " + returnedList.getListError().getValue());
        }

[Solved] What is the proper way to authenticate with Model REST API's?