Refactor of the serialize and to_serializable function

This commit tries to tackle #268 and rewrite the `serialize` function to
handle less class specific cases and move it into the single
dispatch function `to_serializable`.

Author: raphaelahrens

pytm/pytm.py

@@ -1278,7 +1278,6 @@ def get_table(db, klass):
         db.close()
 
 
-
 class Controls:
     """Controls implemented by/on and Element"""
 
@@ -2004,52 +2003,75 @@ def to_serializable(val):
 
 @to_serializable.register(TM)
 def ts_tm(obj):
-    return serialize(obj, nested=True)
+    result = serialize(obj, nested=True, ignore=(
+        "_sf", "_duplicate_ignored_attrs", "_threats", "_elements", "assumptions"))
+    result["elements"] = [e for e in obj._elements if isinstance(e, (Actor, Asset))]
+    result["assumptions"] = list(obj.assumptions)
+    return result
 
 
 @to_serializable.register(Controls)
 @to_serializable.register(Data)
+@to_serializable.register(Finding)
+def _(obj):
+    return serialize(obj, nested=False)
+
+
 @to_serializable.register(Threat)
-@to_serializable.register(Element)
+def _(obj):
+    result = serialize(obj, nested=False, ignore=["target"])
+    result["target"] = [v.__name__ for v in obj.target]
+    return result
+
+
 @to_serializable.register(Finding)
+def _(obj):
+    return serialize(obj, nested=False, ignore=["element"])
+
+
+@to_serializable.register(Element)
 def ts_element(obj):
-    return serialize(obj, nested=False)
+    result = serialize(obj, nested=False, ignore=("_is_drawn", "uuid", "levels", "sourceFiles", "assumptions", "findings"))
+    result["levels"] = list(obj.levels)
+    result["sourceFiles"] = list(obj.sourceFiles)
+    result["assumptions"] = list(obj.assumptions)
+    result["findings"] = [v.id for v in obj.findings]
+    return result
 
 
-def serialize(obj, nested=False):
+@to_serializable.register(Actor)
+@to_serializable.register(Asset)
+def _(obj):
+    # Note that we use the ts_element function defined for the Element class
+    result = ts_element(obj)
+    result["__class__"] = obj.__class__.__name__
+    return result
+
+
+def serialize(obj, nested=False, ignore=None):
     """Used if *obj* is an instance of TM, Element, Threat or Finding."""
     klass = obj.__class__
     result = {}
-    if isinstance(obj, (Actor, Asset)):
-        result["__class__"] = klass.__name__
+    if ignore is None:
+        ignore = []
+
     for i in dir(obj):
         if (
             i.startswith("__")
             or callable(getattr(klass, i, {}))
-            or (
-                isinstance(obj, TM)
-                and i in ("_sf", "_duplicate_ignored_attrs", "_threats")
-            )
-            or (isinstance(obj, Element) and i in ("_is_drawn", "uuid"))
-            or (isinstance(obj, Finding) and i == "element")
+            or i in ignore
         ):
             continue
         value = getattr(obj, i)
-        if isinstance(obj, TM) and i == "_elements":
-            value = [e for e in value if isinstance(e, (Actor, Asset))]
         if value is not None:
             if isinstance(value, (Element, Data)):
                 value = value.name
-            elif isinstance(obj, Threat) and i == "target":
-                value = [v.__name__ for v in value]
-            elif i in ("levels", "sourceFiles", "assumptions"):
-                value = list(value)
             elif (
                 not nested
                 and not isinstance(value, str)
                 and isinstance(value, Iterable)
             ):
-                value = [v.id if isinstance(v, Finding) else v.name for v in value]
+                value = [v.name for v in value]
         result[i.lstrip("_")] = value
     return result