Using GTL for Nested JSON in Marketing Cloud Email HTML

Question

Working on parsing some JSON in the HTML of a Marketing Cloud email using GTL and AMPscript and I've figured out how to do one degree of nesting, but can't figure out how to dig down deeper than that. This is a piece of the sample JSON:

   {
"section": {
    "id": "ABCDEFG",
    "heading": {
        "name": "John Smith"}}
    }

I can get it to pull "id", but not "name". What I used to successfully get to "id":

%%[
SET @title="TestTitle"
SET @JSON=Lookup("TestJSON","JSON", "Title", @title)
]%%  

{{.datasource JsonVar type=variable source=@Json maxrows=20}}
{{.data}}
{"target": "@Json"}
{{/data}}
    {{.datasource section type=nested source=@Json maxrows=20}}
 {{.data}}
      {"target": "JsonVar.section" }
  {{/data}}

%%[
SET @id = TreatAsContent('{{section.id}}')
]%%

  {{/datasource}} 
      {{/datasource}}

That works great, but when I try to reach further down to "name", I can't find a way to make that work. I've tried several AMPscript based things, and also tried adjusting to {"target": "JsonVar.section.heading" } and TreatAsContent('{{section.heading.name}}') but those didn't work. Is there a way to set up another layer of nesting within the above?

Answer 1

You are on the right track, but you shouldn't include a source attribute for nested objects.

The following code will work. As your key names are unique, it's not required to express them in dot notation in your TreatAsContent argument.

%%[
var @json
set @json= '{
    "section": {
    "id": "ABCDEFG",
    "heading": {
        "name": "John Smith"}
    }
}'
]%%  

{{.datasource obj type=variable source=@json}}
  {{.data}}
    {"target": "@json"}
  {{/data}}
    {{.datasource section type=nested}}
     {{.data}}
        {"target": "obj.section" }
      {{/data}}
      {{.datasource section type=nested}}
         {{.data}}
            {"target": "section.heading" }
          {{/data}}

%%[
var @id, @name
set @id = TreatAsContent('{{id}}')
set @name = TreatAsContent('{{name}}')
OutputLine(Concat(@id))
OutputLine(Concat(@name))
]%%

     {{/datasource}} 
  {{/datasource}}
{{/datasource}} 

Update

Here's an additional example of deeper object nesting (based on a comment to my answer). Note, you don't need to use TreatAsContent to set values as variables if you just want to display the values inline.

%%[
var @json
set @json=   '{
   "section":{
      "id":"ABCDEFG",
      "heading":{
         "name":"John Smith",
         "address":{
            "billingAddress":{
               "street":"3 Sample St",
               "city":"London",
               "country":"United Kingdom",
               "postcode":"E1 ABC"
            },
            "postalAddress":{
               "street":"3 Marketing Lane",
               "city":"London",
               "country":"United Kingdom",
               "postcode":"E2 DEF"
            }
         }
      }
   }
}'
]%%  

{{.datasource obj type=variable source=@json}}
  {{.data}}
    {"target": "@json"}
  {{/data}}
    {{.datasource section type=nested}}
     {{.data}}
        {"target": "obj.section" }
      {{/data}}
      {{.datasource heading type=nested}}
         {{.data}}
            {"target": "section.heading" }
          {{/data}}

          id: {{id}}
          name: {{name}}

         {{.datasource address type=nested}}
         {{.data}}
            {"target": "heading.address" }
          {{/data}}

             {{.datasource billingAddress type=nested}}
             {{.data}}
                {"target": "address.billingAddress" }
              {{/data}}

              street: {{street}}
              city: {{city}}
              country: {{country}}
              postcode: {{postcode}}

          {{/datasource}}

             {{.datasource postalAddress type=nested}}
             {{.data}}
                {"target": "address.postalAddress" }
              {{/data}}

              street: {{street}}
              city: {{city}}
              country: {{country}}
              postcode: {{postcode}}

          {{/datasource}} 
        {{/datasource}} 
     {{/datasource}} 
  {{/datasource}}
{{/datasource}}