Generating an ObjectScript Class from JSON Response Using ChatGPT

I have a new project to store information from REST responses into an IRIS database. I’ll need to sync information from at least two dozen separate REST endpoints, which means creating nearly that many ObjectScript classes to store the results from those endpoints.

Could I use ChatGPT to get a headstart on creating these classes? The answer is “Yes”, which is great since this is my first attempt at using generative AI for something useful. Generating pictures of giraffes eating soup was getting kind of old….

Here’s what I did:

• Get some sample JSON REST call output using “curl” to query the endpoint.
• Visit ChatGPT (InterSystems provides a company-wide license for employees)
• Have the following dialog with ChatGPT.

I put the following request in the “Message ChatGPT” prompt:

Me: Generate an ObjectScript class that will hold data from the following JSON:

I hit “Return” before entering the JSON so ChatGPT directed me as follows:

ChatGPT: Please provide the JSON structure you'd like me to generate the ObjectScript class for. If you have an example JSON object, paste it here, and I'll create the corresponding InterSystems ObjectScript class for you.

I entered the following in the prompt:

{
  "id": 335818632,
  "appId": 113,
  "appName": "Batch",
  "contentId": 182455380233,
  "subject": "Test Subject",
  "name": "Test email campaign name",
  "counters": {
    "processed": 3910,
    "deferred": 86,
    "unsubscribed": 17,
    "statuschange": 17,
    "bounce": 153,
    "mta_dropped": 8,
    "dropped": 299,
    "delivered": 3749,
    "sent": 3903,
    "click": 16,
    "open": 323
  },
  "lastProcessingFinishedAt": 1733232499000,
  "lastProcessingStartedAt": 1733232303000,
  "lastProcessingStateChangeAt": 1733232499000,
  "numIncluded": 4201,
  "processingState": "DONE",
  "scheduledAt": 1733232300000,
  "type": "BATCH_EMAIL"
}

ChatGPT’s response:

Here is the InterSystems ObjectScript class that maps to the provided JSON structure:

Class MyNamespace.MyJSONData Extends (%Persistent, %JSON.Adaptor)
{
Property id As %Integer;
Property appId As %Integer;
Property appName As %String;
Property contentId As %Integer;
Property subject As %String;
Property name As %String;
Property counters As MyNamespace.Counters;
Property lastProcessingFinishedAt As %BigInt;
Property lastProcessingStartedAt As %BigInt;
Property lastProcessingStateChangeAt As %BigInt;
Property numIncluded As %Integer;
Property processingState As %String;
Property scheduledAt As %BigInt;
Property type As %String;
ClassMethod %OnJSONImport(jsonObject As %Object, instance As MyNamespace.MyJSONData) As %Status
{
    Quit ..%JSONImport(jsonObject, .instance)
}
}

Class MyNamespace.Counters Extends (%SerialObject, %JSON.Adaptor)
{
Property processed As %Integer;
Property deferred As %Integer;
Property unsubscribed As %Integer;
Property statuschange As %Integer;
Property bounce As %Integer;
Property mta_dropped As %Integer;
Property dropped As %Integer;
Property delivered As %Integer;
Property sent As %Integer;
Property click As %Integer;
Property open As %Integer;
}

Along with an Explanation:

This code is a great start, but I would like it to fit into my package named “MyPkg” and give the name “EmaiCampaign” to the class. Also, using a bit of NI, I know the values which generated the “%BigInt” properties are actually Linux times and the properties should be %Library.PosixTime”.

I make the following request (not sure why I'm saying “please” to a machine; I guess my parents did a good job):

Me: Can we recreate the class again please, renaming the package " MyPkg" and the Class as "EmailCampaign"? Also, please change types of Properties from %BigInt to %Library.PosixTime.

ChatGPT’s response:

Here's the updated ObjectScript class with the specified package name and class name, and the timestamp properties updated to use %Library.PosixTime:

Class MyPkg.EmailCampaign Extends (%Persistent, %JSON.Adaptor)
{
Property id As %Integer;
Property appId As %Integer;
Property appName As %String;
Property contentId As %Integer;
Property subject As %String;
Property name As %String;
Property counters As MyPkg.Counters;
Property lastProcessingFinishedAt As %Library.PosixTime;
Property lastProcessingStartedAt As %Library.PosixTime;
Property lastProcessingStateChangeAt As %Library.PosixTime;
Property numIncluded As %Integer;
Property processingState As %String;
Property scheduledAt As %Library.PosixTime;
Property type As %String;
ClassMethod %OnJSONImport(jsonObject As %Object, instance As MyPkg.EmailCampaign) As %Status
{
    Quit ..%JSONImport(jsonObject, .instance)
}
}

Class MyPkg.Counters Extends (%SerialObject, %JSON.Adaptor)
{
Property processed As %Integer;
Property deferred As %Integer;
Property unsubscribed As %Integer;
Property statuschange As %Integer;
Property bounce As %Integer;
Property mta_dropped As %Integer;
Property dropped As %Integer;
Property delivered As %Integer;
Property sent As %Integer;
Property click As %Integer;
Property open As %Integer;
}

Along with this explanation:

After copying the code “as is” into VSCode, syntax issues with the curly braces were highlighted. ObjectScript classes don’t enable internal class definitions.

Asking ChatGPT to fix the “curly brackets” issue by making the MyPkg.Counters internal class a separate class is a “no-op”; a human will need to move that class into another file. ChatGPT did rename that class after the following request:

Me: The class as it is written does not compile. Can we move the internal class named MyPkg.Counters out of the main class into its own class and rename it to MyPkg.CampaignCounters?

ChatGPT’s response:

Here's the updated ObjectScript code with the MyPkg.CampaignCounters class moved out as its own class:

Class MyPkg.EmailCampaign Extends (%Persistent, %JSON.Adaptor)
{
Property id As %Integer;
Property appId As %Integer;
Property appName As %String;
Property contentId As %Integer;
Property subject As %String;
Property name As %String;
Property counters As MyPkg.CampaignCounters;
Property lastProcessingFinishedAt As %Library.PosixTime;
Property lastProcessingStartedAt As %Library.PosixTime;
Property lastProcessingStateChangeAt As %Library.PosixTime;
Property numIncluded As %Integer;
Property processingState As %String;
Property scheduledAt As %Library.PosixTime;
Property type As %String;
ClassMethod %OnJSONImport(jsonObject As %Object, instance As MyPkg.EmailCampaign) As %Status
{
    Quit ..%JSONImport(jsonObject, .instance)
}
}

Class MyPkg.CampaignCounters Extends (%SerialObject, %JSON.Adaptor)
{
Property processed As %Integer;
Property deferred As %Integer;
Property unsubscribed As %Integer;
Property statuschange As %Integer;
Property bounce As %Integer;
Property mta_dropped As %Integer;
Property dropped As %Integer;
Property delivered As %Integer;
Property sent As %Integer;
Property click As %Integer;
Property open As %Integer;
}

After pasting the above into VSCode and compiling it, the compiler reported that the type named “%Object” does not exist in ObjectScript. According to the IRIS documentation, the property for the first parameter of %JSON.Adaptor’s %JSONImport() method is flexible:

“The input argument is either JSON as a string or stream, or a subclass of %DynamicAbstractObject.”

After removing the “As %Object” property for %OnJSONImport()’s first parameter in the first class and separating the two classes into separate files, the MyPkg.EmailCampaign class compiled successfully. However, the MyPkg.CampaignCounters did not compile; ChatGPT doesn’t (yet?) know that the underscore is a special character in ObjectScript (the string concatenation operator).  

Let’s try to teach it.

Me: The underscore character "_" is a special character in ObjectScript. Please change properties with an underscore in their names to camel case names and remove the underscore.

ChatGPT’s response:

Here is the updated code with properties that had underscores in their names converted to camel case:

Class MyPkg.EmailCampaign Extends (%Persistent, %JSON.Adaptor)
{
Property id As %Integer;
Property appId As %Integer;
Property appName As %String;
Property contentId As %Integer;
Property subject As %String;
Property name As %String;
Property counters As MyPkg.CampaignCounters;
Property lastProcessingFinishedAt As %Library.PosixTime;
Property lastProcessingStartedAt As %Library.PosixTime;
Property lastProcessingStateChangeAt As %Library.PosixTime;
Property numIncluded As %Integer;
Property processingState As %String;
Property scheduledAt As %Library.PosixTime;
Property type As %String;
ClassMethod %OnJSONImport(jsonObject As %Object, instance As MyPkg.EmailCampaign) As %Status
{
    Quit ..%JSONImport(jsonObject, .instance)
}
}

Class MyPkg.CampaignCounters Extends (%SerialObject, %JSON.Adaptor)
{
Property processed As %Integer;
Property deferred As %Integer;
Property unsubscribed As %Integer;
Property statusChange As %Integer;
Property bounce As %Integer;
Property mtaDropped As %Integer;
Property dropped As %Integer;
Property delivered As %Integer;
Property sent As %Integer;
Property click As %Integer;
Property open As %Integer;
}

Along with this explanation:

ChatGPT went above and beyond and changed another property, one named with two separate words, into camel case as well (statuschange); I’m keeping that change since other similarly-named properties in the main class are all camel case.

With the latest generated code in two separate files (and removing the “As %Object” definition in the %OnJSONImport() method definition), all of the code compiles successfully.

These generated classes are an excellent starting point for what I need and I will repeat the process for the other REST data sources for this project, saving me from a lot of unnecessary typing.