transformers.py

class SubformsTransformer(object):
    order = -100      # this should to be executed as first as possible
    block_type = None
    iface = None

    def __init__(self, context, request):
        self.context = context
        self.request = request

    def _transform(self, blocks):
        for id, block_value in blocks.items():
            block_type = block_value.get("@type", "")
            handlers = []
            for h in subscribers(
                (self.context, self.request),
                self.iface
            ):
                if h.block_type == block_type or h.block_type is None:
                    h.blockid = id
                    handlers.append(h)

            for handler in sorted(handlers, key=lambda h: h.order):
                block_value = handler(block_value)

            blocks[id] = block_value

        return blocks

    def __call__(self, block_value):
        if not isinstance(block_value, dict):
            return block_value

        if 'data' in block_value:
            if isinstance(block_value['data'], dict):
                if 'blocks' in block_value['data']:
                    block_value['data']['blocks'] = self._transform(
                        block_value['data']['blocks']
                    )

        if 'blocks' in block_value:
            block_value['blocks'] = self._transform(block_value['blocks'])

        return block_value


@implementer(IBlockFieldSerializationTransformer)
@adapter(Interface, IBrowserRequest)
class SubformsSerializationTransformer(SubformsTransformer):
    iface = IBlockFieldSerializationTransformer


@implementer(IBlockFieldSerializationTransformer)
@adapter(Interface, IBrowserRequest)
class SubformsDeserializationTransformer(SubformsTransformer):
    iface = IBlockFieldDeserializationTransformer