To send JSON with an HTTP POST request using InterSystems ObjectScript, you can use the %Net.HttpRequest class. Here is a sample code snippet demonstrating how to do this:

Create an HTTP request object.
Set the server URL and other necessary properties.
Write the JSON payload to the request’s entity body.
Send the POST request.

Here is an example:

Set Body={}
Set Body.Name="John Smith"
Set Body.Address="ISC Dev community"
Set Body.SomeProperty="Some content"
Set Request = ##class(%Net.HttpRequest).%New()
Set Request.Server = "server"
Set Request.Location = "location"
Set Request.ContentType = "application/json"
// Convert the object to JSON and write it to the request's entity body
Do Body.%ToJSON(Request.EntityBody)

// Send the POST request
Set Status = Request.Post()

This is the expected behavior as documented in Message Contents

Management Portal displays only the first 20000 characters of the message by default, this can be changed as documented in Changing the Character Limit for XML Messages in the Contents Tab

So, in your case for only EnsLib.HTTP.GenericMessage you can:

Set ^EnsPortal.Settings("All","MessageContents","OutputSizeLimit","EnsLib.HTTP.GenericMessage")=<whatever size you feel appropriate>

or for any class:

Set ^EnsPortal.Settings("All","MessageContents","OutputSizeLimit")=<whatever size you feel appropriate>

Where are you seeing "DTL response = <ID scope='Message'>3</ID>"?

What you see is the "representation", the "export" of your XML enabled class rendered by...whatever you are using to view/display it, the quotes are not part of the content.

How are you using/consuming your target (DTL response)? Some XML (SOAP? REST?) message? If so, I believe that you won't find single quotes when you will use it.

This is just guessing, because you don't provide any context/detail.

Following your enthusiasm I implemented a little test 😁

Class Community.Array.Base Extends (%RegisteredObject, %XML.Adaptor, %JSON.Adaptor)
{

Property Slide As list Of Community.Array.Slide(XMLPROJECTION = "ELEMENT");

ClassMethod test()
{
	Set Base=##class(Community.Array.Base).%New()
	For i=1:1:3 {
		Set Slide=##class(Community.Array.Slide).%New()
		Set Slide.Name="Name"_i
		Do Base.Slide.Insert(Slide)
	}
	Do Base.XMLExport(,",indent")
	Write !,"JSON: ",!
	Do Base.%JSONExport()
}

}

Class Community.Array.Slide Extends (%RegisteredObject, %XML.Adaptor, %JSON.Adaptor)
{

Property Name As %String;

}

The output is:

USER>Do ##class(Community.Array.Base).test()
<Base>
  <Slide>
    <Name>Name1</Name>
  </Slide>
  <Slide>
    <Name>Name2</Name>
  </Slide>
  <Slide>
    <Name>Name3</Name>
  </Slide>
</Base>
 
JSON:
{"Slide":[{"Name":"Name1"},{"Name":"Name2"},{"Name":"Name3"}]}

Is this what you need?

We are not InterSystems support team, we are a Developer Community. 😊

You can download it from WRC (Worldwide Response Center) portal, the official InterSystems Support.

If your system is under support/maintenance you should have access to it.

If you your system is not covered by support/maintenance, you are not entitled to updates.

For testing purpose you may use/download IRIS Community Edition.

I'm trying to convert date - 2023-09-28T20:35:41Z to BST/GMT format.

Please note that BST and GMT are not "format" and (may) have different values.
From your answer to @Robert Cemper it seems you need to covert to BST value (not GMT) and to "yyyymmddhhmmss" format.

To answer your question, is BST your system local timezone?

If you don't like the default behavior, change it. 😊

You can change it system wide from Management Portal, System Administration -> Security -> System Security -> System-wide Security Parameters
There you can change "Inactive limit" to 0 (zero), this way accounts never expire.

You can also change it for any individual user accounts in Management Portal, System Administration -> Security -> Users -> (select the user)
There you can enable the checkbox "Account Never Expires".

You have a superclass with some logging method. Now every time the logging method is called from a child class it logs the name of the superclass instead of the Child class?

No

If so the issue is that $CLASSNAME returns the name of the class where the method is located not where a method is called from.

Wrong, it returns the class name where it is called from.

Your first sample method works just fine, no need for method generator.

I suggest you to make a quick test.