Generate JSON With JSON-Views

Question

I am trying to use JSON-Views in Grails 3.1.

I have the following controller:

package myapp

BasketController {

    def index(ProductFilterCommand cmd) {

        [basketList: service.findAllBaskets()]
    }
}

And the following classes:

package myapp

class Basket {
    List<BasketItem> items
}

class BasketItem  {
    String name 
}

Here are the gson files which I thought would work:

basket/index.gson

import myapp.Basket

model {
    Iterable<Basket> basketList
}

json.baskets(basketList) {
    g.render(template: "basket", model: [basket: it])
}

basket/_basket.gson

import myapp.Basket

model {
    Basket basket
}

json.items(basket.items) { 
    g.render(template: "item", model:[item: it])
}

basket/_item.gson

import myapp.Item

model {
    Item item
}

json g.render(item)

I want to generate json such as:

{
    "baskets": [{
        "items": [{
            "name": "T-shirt"
        }, {
            "name": "Pants"
        }]
    }, {
        "items": [{
            "name": "T-shirt"
        }, {
            "name": "Pants"
        }]
    }]
}

But instead I am getting:

{
  "baskets": [
    {},
    {}
  ]
}

Thanks @dmahapatro It worked perfectly. I've accepted your answer. Sorry for my late answer. they were not domain classes juts plain groovy classes. — Sergio del Amo, Feb 10 '16 at 09:46
For POGO unlike domain classes, all these ceremony and templates are not required, just `json { baskets basketList }` in `index.gson` would give expected result, hence my question previously. Obviously you would need the `model` dsl for basketList though. :) — dmahapatro, Feb 10 '16 at 11:11

score 10 · Accepted Answer · answered Feb 09 '16 at 02:20

Looks like a bug to me. The only way to achieve what you are looking for is to use the views as shown below. Also note the usage of collection instead of model. I would file a bug with the sample app I used to test below.

Note the usage of template as a fully qualified name basket/item. This is the defect.

//index.gson
import com.example.Basket

model {
    Iterable<Basket> basketItems
}

json {
    baskets g.render(template: 'basket', collection: basketItems, var: 'basket')
}

//_basket.gson
import com.example.Basket

model {
    Basket basket
}

json {
    items g.render(template: "basket/item", collection: basket.items, var: 'item')
}

//_item.gson
import com.example.BasketItem

model {
    BasketItem item
}

json g.render(item)

//or if id is not required in response
/*json {
    name item.name
}*/

I have this problem with views-1.1.5. The show.gson gets executed and the json output is good. But the index.gson doesnt seem to invoke at all. I had a System.out.println in index.gson to confirm. — Umapathy, Feb 16 '17 at 12:33

Generate JSON With JSON-Views

1 Answers1