Hydrate JSON templates & conditional rendering

[cka29]

Hi,
is there a Stac-native way to hydrate the json templates with data before rendering? Like for example have placeholders:

{
  "type":  "text",
  "data":  "{{ title }}",
  "style":  {
    "color":  "#FFFFFF",
    "fontSize":  24.0
  }
}

Or do we have to do this manually with replace regex.

Second question:
Is there a way to conditionally render widgets from the JSON? for example a config like this

{
  "type":  "text",
  "render": myCondition,
  "data":  "Hello, World!",
  "style":  {
    "color":  "#FFFFFF",
    "fontSize":  24.0
  }
}

Thanks!

[divyanshub024]

Hey @cka29,

I've created a draft PR for Stac dynamic view, which fetches and renders API data. Can you please check if it solves your first purpose?

#208

[cka29]

looks good to me thank you! But I didn't meant to use a request inside the stac template. Our use case needs to hydrate the JSON when it's received on the client. For example if we have an internal User object (that is already fetched separately and we'd have to replace the placeholders {{ firstName }} and {{ email }} when rendering. I thought maybe we can provide a view model to the stac parsers custom widget and then pick the correct fields or similar. Do you know what I mean? I'm sorry for confusing you!

Thats why I was asking

Or do we have to do this manually with replace regex.

[divyanshub024]

Hey @cka29, I think I’ve got a rough idea. Could you share a specific scenario or some sample code so I can better understand exactly what you’re trying to achieve?

[cka29]

Sure, here is some pseudo code, I hope this makes it more clear:

class User {
  final String name;
  const User({required this.name});
}

const template = '''
  {
    "type":  "text",
    "data":  "{{ name }}",
    "style":  {
      "color":  "#FFFFFF",
      "fontSize":  24.0
    }
  }
''';

const dataFromAPi = User(name: "John");

Widget build() {
  return CustomStacUserWidget(
    template: template,
    data: dataFromAPi,
  );
}

I know there is the easy way to achieve this, which would be just to replace {{ name }} with regex and some User model logic to extract the properties, but I'd like to know if you had plans to implement such feature inside the framework itself. Thank you!

[divyanshub024]

Hey @cka29! Sorry, we don’t have plans to add this to the framework at the moment. But if more users request it, we’ll definitely consider it.
In the meantime, you can get it working just like you mentioned, by using a custom widget parser and regex.

[cka29]

@divyanshub024 thank you for your help and sorry again for the misunderstanding in the beginning! 🙏

[divyanshub024]

Don’t be sorry 🙂 Honestly, we really appreciate you helping us make Stac better!