Compile applications

Compile applications and services.

1. With a text editor, create an application source file called helloapp.4gl .
   In it copy the code shown in the example and save:

   IMPORT FGL fgldialog
   
   MAIN
     OPEN FORM f FROM "helloapp"
     DISPLAY FORM f
   
     MENU "Exit"
       COMMAND "Hello"
         CALL fgl_winmessage("Hello", "Hello World!", "exclamation")
       COMMAND "exit"
         EXIT MENU
     END MENU
   END MAIN

2. To create the application form, create a file called helloapp.per
   Copy the code shown in the example and save:

   LAYOUT(TEXT="Hello World")
   GRID
   {
       Hello World!
   }
   END

3. To create a service application, create a file called helloservice.4gl
   Copy the code shown in the example and save:

   IMPORT XML
   IMPORT COM
   
   &define L(s) DISPLAY SFMT("(%1:%2) %3", __FILE__, __LINE__, s)
   &define LF(s) L(SFMT s)
   
   # Query string parameters
   TYPE QSParams DYNAMIC ARRAY OF RECORD
       name STRING,
       value STRING
     END RECORD
   
   MAIN
     DEFINE url,
            qs,
            requestUrl STRING
     DEFINE request com.HTTPServiceRequest
   
     CALL com.WebServiceEngine.Start()
   
     WHILE TRUE
       TRY
         #Retrieve the HTTPServiceRequest object to handle the HTTP request in various FUNCTIONs
         LET request = com.WebServiceEngine.GetHttpServiceRequest(-1)
   
         #Separate the incoming URL from query string
         LET requestUrl = request.readFormEncodedRequest(false)
         CALL splitUrl(requestUrl) RETURNING url, qs
         CALL processRequest(request, requestUrl)
       CATCH
         LF(("Exception %1 - %2", status, SQLCA.SQLERRM))
         L("Got an exception - Exiting")
         EXIT WHILE
       END TRY
     END WHILE
   END MAIN
   
   { Split an url and returns (path, query string) }
   FUNCTION splitUrl(url)
     DEFINE url STRING
     DEFINE i INTEGER
   
     IF url IS NULL THEN
       RETURN NULL, NULL
     END IF
   
     LET i = url.getIndexOf("?",1)
     IF i >= 1 THEN
       RETURN url.subString(1, i - 1), url.subString(i + 1, url.getLength())
     END IF
   
     RETURN url, NULL
   END FUNCTION
   
   FUNCTION processRequest(request, requestUrl)
     DEFINE request com.HTTPServiceRequest,
            requestUrl STRING
   
     LF(("processRequest: %1", requestUrl))
   
     CALL request.sendTextResponse(200, "OK", "Hello World!")
   END FUNCTION
   

4. Compile the application and service source files (4gl and per).
   Run the commands shown at the command line:

   fglcomp -r -M helloapp.4gl
   fglform -M helloapp.per
   fglcomp -r -M helloservice.4gl
   

   The application and service 42m and 42f files are created.