message: Introducing support for pre-depercate_v1 URL scheme
diff: @@ -38,6 +38,7 @@ from superset import (
  appbuilder, cache, db, models, viz, utils, app,
  sm, sql_lab, sql_parse, results_backend, security,
  )
  +from superset.legacy import cast_form_data
  from superset.utils import has_access
  from superset.source_registry import SourceRegistry
  from superset.models import DatasourceAccessRequest as DAR
  @@ -1466,10 +1467,14 @@ class Superset(BaseSupersetView):
  def get_form_data(self):
  form_data = request.args.get("form_data")
  if not form_data:
  + # Supporting POST as well as get
  form_data = request.form.get("form_data")
  - if not form_data:
  - form_data = '{}'
  + if form_data:
  d = json.loads(form_data)
  + elif request.args.get("viz_type"):
  + # Converting old URLs
  + d = cast_form_data(request.args.to_dict())
  +
  extra_filters = request.args.get("extra_filters")
  filters = d.get('filters', [])
  if extra_filters:
  