JSON Syntax

Question

Question

Rui Figueiredo · Nov 19, 2018

Hi,

I'm using InterSystem Cache v2015.2.5 and I'm implementing a REST API and returning JSON.

Following the documentation I see examples like this

Set obj = {"destinations": ["London","Madrid","Tokyo"]}
Write obj.%ToJSON()

However, I have a compilation error

ERROR #1054: Invalid expression : '{"destinations":'

Is there something that needs to be enabled on Studio to allow this syntax?

Thank you,

Rui

Discussion (5)1

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Sean Connelly · Nov 19, 2018

Hi Rui,

This JSON feature is only available from 2016.1 onward.

Take a look at this post for an alternative way to output JSON

0 0

score 0 · Answer 1 · 2018-11-19T12:12:06-05:00

Using %DynamicObject throws an exception at runtime

ERROR #5002: Cache error: <CLASS DOES NOT EXIST>zGetED0005A+84^xxxxxxx *%Library.DynamicObject

score 0 · Answer 2 · 2018-11-19T11:57:29-05:00

I think you need to work with this

set obj = ##class(%DynamicObject).%New()

do obj.Destinations.SetAt("London", counter)
Add to this obj your destinations as you would add to an array property and then do ToJson

score 0 · Answer 3 · 2018-11-19T12:43:32-05:00

Neerav Verma · Nov 19, 2018

Ok version issue

i am using 2017.2.2

0 0

score 0 · Answer 4 · 2018-11-19T14:45:34-05:00

After some investigation here is some code that works on v2015.2

// to create a dynamic array
SET results = ##class(%ListOfDataTypes).%New()

// to create a dynamic object
SET obj = ##class(%ZEN.proxyObject).%New()
SET obj.name = "John doe"

// add obj to the array
results.Insert(obj)

// create dynamic response object
SET response = ##class(%ZEN.proxyObject).%New()
SET response.Results = results

Write response.%ToJSON()

---------------------------------------------

{
"Results": [
{
"name": "John Doe"
}
]
}

Thanks,

Rui