Step 6: Create the server

I4GL uses Axis as server for its services, but Genero has its own server programmable via the COM library. Create a new file and add the IMPORT com instruction at beginning of the server file, then simply create the main loop in 4GL that will process any incoming HTTP request.

The port of the service defined in the I4GL .4cf configuration file (via the PORTNO entry) can be reused by setting the FGLAPPSERVER environment variable to the same value before to run the server. However only on development or for tests, on production Genero Web services requires an application server called GAS in charge of load balancing. See the GAS documentation for more details about port configuration for deployment purpose.

For example, to migrate the I4GL zipcode demo, the service must be created in the server before run the main loop as following :

MAIN
  DEFINE ret INTEGER
  DEFER INTERRUPT

  # Create zipcode_details service
  CALL create_zipcode_details_web_service()

  # Start the server on port set in FGLAPPSERVER
  #    (to be set to same value as PORTNO defined in the .4cf file)
  CALL com.WebServiceEngine.Start()

  # Handle any incoming request
  WHILE TRUE
    LET ret = com.WebServiceEngine.ProcessServices(-1)
    CASE ret
      WHEN 0
        DISPLAY "Request processed."
      WHEN -1
        DISPLAY "Timeout reached."
      WHEN -2
        DISPLAY "Disconnected from application server."
        EXIT PROGRAM   # The Application server has closed the connection
      WHEN -3
        DISPLAY "Client Connection lost."
      WHEN -4
        DISPLAY "Server interrupted with Ctrl-C."
      WHEN -10
        DISPLAY "Internal server error."
      END CASE
      IF int_flag<>0 THEN
        LET int_flag=0
        EXIT WHILE
      END IF   
   END WHILE
END MAIN

Note: With Genero Web Services, one server can contain several services. In other words, you can put all your I4GL services into one server.