Use IBlocks identifier to get Objects with blocks, make use of visit_…

…blocks function to get nested blocks

src/plone/restapi/services/blocktypes/get.py

@@ -1,7 +1,8 @@
 from plone import api
 from plone.restapi.services import Service
 from collections import Counter
-from plone.dexterity.content import get_assignable
+from plone.restapi.behaviors import IBlocks
+from plone.restapi.blocks import visit_blocks
 
 
 class BlockTypesGet(Service):
@@ -14,26 +15,17 @@ def reply(self):
             blocktypes = request_body.get("blocktypes").split(",")
 
             for blocktype in blocktypes:
-                brains = catalog.searchResults(block_types=blocktype)
+                brains = catalog(object_provides=IBlocks.__identifier__)
                 result[blocktype] = Counter()
 
                 for brain in brains:
                     obj = brain.getObject()
-                    assignable = get_assignable(obj)
+                    url = brain.getPath() # or .getURL()
+                    title = obj.title
+                    result[blocktype][title] = Counter()
 
-                    hasBlocksBehavior = bool(
-                        {
-                            behavior
-                            for behavior in assignable.enumerateBehaviors()
-                            if behavior.name == "volto.blocks"
-                        }
-                    )
-
-                    if hasBlocksBehavior:
-                        url = brain.getURL()  # or brain.getPath()
-
-                        for block in obj.blocks.values():
-                            if block["@type"] == blocktype:
-                                result[blocktype].update({url: 1})
+                    for block in visit_blocks(obj, obj.blocks):
+                        if block["@type"] == blocktype:
+                            result[blocktype][title].update({url: 1})
 
         return result