Using cWebHttpHandler with JSON instead of tWebValueTree

From this forum post: https://support.dataaccess.com/Forums/showthread.php?68231-ToDo-Describe-call-mode-and-a-few-more-questions&p=371095#post371095

Reposting it here so I can quickly find it next time I need it (sorry, not sorry)

It is indeed true that for most situations the tWebValueTree is not needed any more. ClientActions and ServerActions can now use JSON Handles or structs & arrays that are directly serialized. So when calling a server action you can now do the following:

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//  Create data objects    var oData =  {     labels : ["January","February","March","April","May","June","July"],     datasets : [{         strokeColor : "rgba(220,220,220,1)",         data : [65,59,90,81,56,55,40]     },{         strokeColor : "rgba(151,187,205,1)",         data : [28,48,40,19,96,27,100]     }] };   //  Send call to the server this.serverAction("ProcessData2", [ 2, 1 ], oData, function(oEvent){     alert(oEvent.sReturnValue); });

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//  Function called as server action Function ProcessData2 Integer iParam1 Integer iParam2 Returns String     tActionData tData     Handle hoJson           //  Retrieve and deserialize data     Get phoActionJsonData to hoJson     Get JsonToDataType of hoJson to tData           Function_Return tData.labels[3] End_Function

So instead of ptActionData you use phoActionJsonData which gives a cJsonObject representing the data. Note that you do not have to cleanup this JSON Handle.

For client actions you can do the following:

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Procedure ProcessDataOnClient2     //  Send the client action     String[] aParams     tActionData tData            //  Generate some data     Move "Januari"      to tData.labels[0]     Move "Februari"     to tData.labels[1]     Move "#FF0000"      to tData.datasets[0].strokeColor     Move 55             to tData.datasets[0].data[0]     Move 88             to tData.datasets[0].data[0]            //  Call the client action     Send ClientAction "processData2" aParams tData End_Procedure

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//  Client action called with action data processData2 : function(){     var tData;           // Retrieve value tree and deserialize     tData = this._tActionData;           // Do something with the data     alert(tData.datasets[0].strokeColor); }

Note that ClientAction takes a variant parameter that it serializes to JSON. Both API's are backwards compatible so working with tWebValueTree still works. The value tree's are also still used for client web properties.