4 Replies Latest reply: Oct 15, 2014 2:42 PM by Shane Porter RSS

    Engine API - ValueExpression

      Hi everyone,


      My aim is to evaluate a number of expressions, hopefully as a single call, using the Engine API and Web socket requests from a web browser.   I have a couple of questions.


      Referring to this:



      I see that the aim is to evaluate the expression =Count(CategoryName)

      So why does the example's request parameter contain a reference to qFieldDefs (country) and so on? I've managed to reduce the parameter to:



        "jsonrpc": "2.0",

        "id": 1,

        "method": "CreateSessionObject",

        "handle": 1,

        "params": [


            "meta": {

              "data": "this is the data",

              "qValueExpression": "=COUNT(CategoryName)"


            "qInfo": {

              "qId": "",

              "qType": "Listbox"


            "qListObjectDef": {

              "qInitialDataFetch": [


                  "qTop": 0,

                  "qLeft": 1,

                  "qHeight": 1,

                  "qWidth": 1








      and get the result I want.  Can anyone explain why the additional parameters are present in the example? They seem to me to be extraneous.


      Also, can I evaluate multiple expressions with a single call?


      Thanks for your help.





      Message was edited by: Shane Porter Changed request since it wasn't valid.