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· Jan 21, 2020

Converting an object from type %Library.DynamicObject to another type

#JSON #InterSystems IRIS #InterSystems IRIS BI (DeepSee)

I need to convert a JSON payload to a custom object type. Currently, I'm converting the JSON object to a %Library.DynamicObject object and need to proceed from here.

As of now, these are my options

                 1. Using an external library talked about in this link:

https://community.intersystems.com/post/binding-regular-cache-object-dynamicobject-and-vice-versa

Downside: Could be buggy (as admitted by the creator) + some other design concerns brought up in its the discussion thread

 

2. Creating a new object of the desired class and then Iterating through the DynamicObject and populating the new object's fields.

Downside: Having to do this for each type of object individually rather than being able to generalize it (because of the need to instantiate new objects for swizzled objects)

Is there a standard way of doing this?

IRIS for UNIX (Apple Mac OS X for x86-64) 2019.4.0DS (Build 165U)

Discussion (4)1
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Vitaliy Serdtsev · Jan 22, 2020

The example below works even in Caché:

#include %systemInclude
n

try{

  $$$AddAllRoleTemporaryInTry
  n $namespace
  s $namespace="SAMPLES"
  
  s person=##class(Sample.Person).%OpenId(1)
  
  d ##class(%ZEN.Auxiliary.altJSONProvider).%WriteJSONStreamFromObject(.stream,person,,,$$$YES,"aeloq")
  w "json (string): ",stream.Read($$$MaxLocalLength),!!
  
  d ##class(%ZEN.Auxiliary.altJSONProvider).%ConvertJSONToObject(stream,"Sample.Person",.obj)
  w "obj.Home.Street: ",obj.Home.Street ; or d $system.OBJ.Dump(obj)
  
}catch(ex){
  w "Error ", ex.DisplayString(),!
}
Result:

USER>d ^test
json (string): {"Name":"Pascal,Martin F.","SSN":"502-68-5767","DOB":43307,"Home":{"Street":"9347 Franklin Drive","City":"Denver","State":"VA","Zip":66346},"Office":{"Street":"4897 Main Blvd","City":"Miami","State":"MO","Zip":60084},"Spouse":"","FavoriteColors":[],"Age":"60"}
 
obj.Home.Street: 9347 Franklin Drive

Or use %JSON.Adaptor: Exporting and Importing

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Jorge de la Garza · Jan 22, 2020

I'm not sure in what version %JSON.Adaptor was introduced, but if it's in your version, you can have the class modeling your object extend %JSON.Adaptor, which will give you access to the %JSONImport() method, which can de-serialize a JSON payload into an object.

One caveat to this is that I believe any serial objects referenced by the top-level object will also need to extend %JSON.Adaptor for the import to work properly.

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