Add conditional checks when resolving streamfield type (#29)

Author: NathHorrigan

grapple/actions.py

@@ -278,12 +278,17 @@ def convert_to_underscore(name):
 
 
 def streamfield_resolver(self, instance, info, **kwargs):
-    field_name = convert_to_underscore(info.field_name)
-    block = instance.block.child_blocks[field_name]
-    value = instance.value[field_name]
+    value = None
+    if hasattr(instance, "block"):
+        field_name = convert_to_underscore(info.field_name)
+        block = instance.block.child_blocks[field_name]
+        value = instance.value[field_name]
 
-    if issubclass(type(block), ImageChooserBlock) and isinstance(value, int):
-        return block.to_python(value)
+        if not block or not value:
+            return None
+
+        if issubclass(type(block), ImageChooserBlock) and isinstance(value, int):
+            return block.to_python(value)
 
     return value
 

grapple/types/streamfield.py

@@ -39,13 +39,14 @@ def resolve_type(cls, instance, info):
         If block has a custom Graphene Node type in registry then use it,
         otherwise use generic block type.
         """
-        mdl = type(instance.block)
-        if mdl in registry.streamfield_blocks:
-            return registry.streamfield_blocks[mdl]
+        if hasattr(instance, "block"):
+            mdl = type(instance.block)
+            if mdl in registry.streamfield_blocks:
+                return registry.streamfield_blocks[mdl]
 
-        for block_class in inspect.getmro(mdl):
-            if block_class in registry.streamfield_blocks:
-                return registry.streamfield_blocks[block_class]
+            for block_class in inspect.getmro(mdl):
+                if block_class in registry.streamfield_blocks:
+                    return registry.streamfield_blocks[block_class]
 
         return registry.streamfield_blocks["generic-block"]