Working implementation of DefaultDataPresenter

src/workflow/DefaultDataPresenter.py

@@ -0,0 +1,103 @@
+from typing import Any
+
+from core.Expando import Expando
+from workflow.engine import DataPresenter
+
+
+class DefaultDataPresenter(DataPresenter):
+  """Default data presenter that returns the input data unchanged."""
+  
+  def __init__(self, component_id: str, mappings_definition: str):
+    super().__init__(component_id)
+    self._mappings_definition = mappings_definition
+    self._split_definitions = [definition.strip() for definition in mappings_definition.split(",")]
+    
+    if "*" not in mappings_definition:
+      self._static_mappings = self._get_static_mappings()
+    else:
+      self._static_mappings = None
+  
+  def present(self, data: Any) -> Any:
+    self._validate_mappings_definition()
+    
+    if self._static_mappings:
+      return Expando(data.to_dict(self._static_mappings))
+    
+    dynamic_mappings = self._get_dynamic_mappings(data)
+    return Expando(data.to_dict(dynamic_mappings))
+  
+  def _get_dynamic_mappings(self, data):
+    
+    manage_conflicts = {}
+    
+    mappings = {}
+    for mapping in self._split_definitions:
+      if "=" in mapping:
+        key, value = [s.strip() for s in mapping.split('=', 1)]
+        if key == "*":
+          # all fields
+          if value != "*":
+            raise ValueError("Only '*' is accepted when renaming wildcard.")
+          for key in data.as_dict().keys():
+            if key in manage_conflicts:
+              raise ValueError(f"Collision detected for field '{key}'. It is mapped from both '{manage_conflicts[key]}' and '{mapping}'.")
+            manage_conflicts[key] = mapping
+            mappings[key] = key
+        elif key.endswith(".*"):
+          # all fields in a sub-object
+          if value != "*":
+            raise ValueError("Only '*' is accepted when renaming wildcard.")
+          obj_path = key[:-2]
+          sub_obj = data.get(obj_path)
+          if isinstance(sub_obj, dict):
+            for sub_field in sub_obj:
+              if sub_field in manage_conflicts:
+                raise ValueError(
+                  f"Collision detected for field '{sub_field}'. It is mapped from both '{manage_conflicts[sub_field]}' and '{mapping}'.")
+              manage_conflicts[sub_field] = mapping
+              mappings[f"{obj_path}.{sub_field}"] = sub_field
+          else:
+            raise ValueError(f"Field '{obj_path}' is not an object.")
+        else:
+          mappings[key.strip()] = value.strip()
+      
+      
+      else:
+        if mapping == "*":
+          # all fields
+          for key in data.as_dict().keys():
+            mappings[key] = key
+        elif mapping.endswith(".*"):
+          # all fields in a sub-object
+          obj_path = mapping[:-2]
+          sub_obj = data.get(obj_path)
+          if isinstance(sub_obj, dict):
+            for sub_field in sub_obj:
+              mappings[f"{obj_path}.{sub_field}"] = f"{obj_path}.{sub_field}"
+          else:
+            raise ValueError(f"Field '{obj_path}' is not an object.")
+        else:
+          mappings[mapping] = mapping
+    
+    return mappings
+  
+  def _get_static_mappings(self):
+    mappings = {}
+    for mapping in self._split_definitions:
+      if "=" in mapping:
+        key, value = [s.strip() for s in mapping.split('=', 1)]
+        mappings[key] = value
+      else:
+        mappings[mapping] = mapping
+    
+    return mappings
+  
+  def _validate_mappings_definition(self):
+    last_char_was_comma = False
+    for i, char in enumerate(self._mappings_definition):
+      if char == ',':
+        if last_char_was_comma:
+          raise ValueError(f"Invalid mappings definition: Error found at index {i}")
+        last_char_was_comma = True
+      elif not char.isspace():
+        last_char_was_comma = False