This is a tutorial of how to create a new POST type rest data source in Oracle Apex as well as how to call it from a dynamic action. Youtube would not let me put "equal sign greater than sign" in the description. So everywhere you see &&, just replace that with equalgreater for the procedure parameter inputs in the snippet below. I hope this helps someone. Thank you!
DECLARE
l_response CLOB;
l_parameters APEX_EXEC.T_PARAMETERS;
l_rest_static_id VARCHAR2(25) := 'rest_test';--define your rest data source static id
BEGIN
--set your POST body parameter value
APEX_EXEC.add_parameter(p_parameters && l_parameters,
p_name && 'random_name', --the name of your request body parameter
p_value && :P1_TEST_INPUT); --the value you want to set it to
--Execute a POST on your defined rest data source
APEX_EXEC.EXECUTE_REST_SOURCE(
p_static_id && l_rest_static_id,
p_operation && 'POST', --POST
p_parameters && l_parameters
);
--Read the response output parameter from your rest data source
l_response := APEX_EXEC.get_parameter_clob(p_parameters && l_parameters, p_name && 'response');--set name equal to your output body param name
--set a page item to your read response
:P1_RESPONSE := l_response;
END;